Recently, superplasticizers are widely used for producing concrete and improving concrete durability. And in order to reduce environmental loading, set-retarder such as sodium gluconate is attracting attention to control the hydration of cement in the concrete sludge water. In previous paper, we clarified the influence of clay mineral on the fluidity of limestone powder suspension and the adsorption of superplasticizers. In this paper, we investigated the influence of Montmorillonite on the hydration of cement with comb-type superplasticizer or sodium gluconate. We also refered the interaction between the sodium gluconate and clay mineral. The rate of heat liberation of ordinary Portland cement paste was measured by using conduction calorimeter. Using a control stress type rheometer（rotational cylinder viscometer）, the viscosity of ordinary Portland cement paste was measured to estimate the apparent viscosity. And the adsorbed amount of polymer was calculated from the concentrations of the polymer in the initial solution and the liquid phase（after polymer adsorption）. The unadsorbed polymer concentration was measured by Total Organic Carbon Analyzer（TOC）. When the dosage of Montmorillonite increased, the rate of heat liberation of cement with comb-type superplasticizer was changed. However, the rate of heat liberation of cement and the fluidity of cement paste with sodium gluconate were not influenced by addition of Montmorillonite. In the case of comb-type superplasticizers, it is considered that much comb-type superplasticizers adsorbed on Montmorillonite and the amount of adsorbed comb-type superplasticizers on cement relatively decreased. On the other hand, the amount of adsorbed sodium gluconate on Montmorillonite is much lower than comb-type superplasticizers and the amount of adsorbed sodium gluconate on cement did not change.

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This paper investigates hydrothermal synthesis of low water-to-powder light weight concrete containing cenosphere. Cenosphere is lightweight hollow sphere particle which is included in fly ash. The cenosphere in this study is collected from disposal water pool of coal ash in Japan where cenosphere float at the top. The density of cenosphere was about 0.75g/cm³ and median particle size was 159μm. Chemical composition of cenosphere was as same as that of ordinary fly ash in Japan. Cenosphere was mainly composed of glass（67％）and mullite（26％）. The amount of α-quartz in cenosphere（2.4％）was much smaller than fly ash. Using silica fume, viscosity agent and superplasticizer were effective to acquire both flowability of cement paste and prevention of material segregation for the hydrothermal reaction in Low Heat Cement-cenosphere system. The density and compressive strength of samples were ranged from 0.85 to 1.05g/cm³ and 15 to 22N/mm² respectively. When comparing the specific strength of the present study with ordinary cementitious materials without cenosphere, it improved much higher with cenosphere. The surface of cenosphere was reacted, however the shell of cenosphere was remained firmly. In addition, the amount of through pore decreased by the usage of cenosphere and silica fume. Based on the above result, low permeability and high durabirity is expected for the present system.

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Because of the vast utilization of industrial wastes and by-products in cement plant, it is necessary to control the fluidity of cement containing large amount of aluminate phase. In this research, we investigated the effect of fluidity by the addition of free-lime. Cement clinkers were synthesized from industrial raw materials and reagents by using an electric furnace in laboratory. The aluminate phase and F-CaO content for the synthesis of clinkers were varied 9％ & 12％ mass, and 0.24 & 0.31％ mass respectively. Cement samples were prepared by the addition of hemihydrate gypsum and dihydrate gypsum to clinker by adjusting the SO₃ and hemihydrate-gypsum rate to 3％ and 50 mass％ respectively. Then, cement pastes were prepared by the addition of polycarboxylate type superplasticizer under water-cement ratio was 0.32. The apparent viscosity of the cement pastes was measured with a concentric-cylinder type rotational viscometer. The fluidity of the cement paste containing aluminate phase of 12 mass％ increased with increasing amount of f-CaO, reached maximum at 1％ of f-CaO. More than 1％ of f-CaO, the fluidity of the cement paste decreased. The fluidity of the cement paste containing aluminate phase of 12 mass％, and f-CaO of 1％ was further increased by replacing the cement paste with 5％ limestone-powder（LSP）. This enhancement in fluidity may be due to the presence of LSP and f-CaO in cement paste, which control C₃A’s hydration. The fluidity of LSP containing cement paste（12％ mass）is nearly same as the fluidity of the cement paste containing 9 mass％ aluminate phase without LSP. In this study, apparent viscosity of cement pastes was not correlated to the heat generation rates of the cement pastes.

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High volume blast furnace slag（HVBFS）cement is very useful for the reduction of CO₂ in zcement industry. The authors have been proposed HVBFS cement containing more than 70％ blast furnace slag（BFS）and about 15％ ordinary Portland cement（OPC）. But the early hydration of this HVBFS cement is retarded by adding of superplasticizer. This paper discusses the material design for HVBFS cement in consideration of early hydration of cement. The content of anhydrite and OPC, fineness of BFS and the replacement ratio of lime stone powder（LSP）in HVBFS cement have been studied for the improvement of the early hydration properties of HVBFS cement. In addition, the hydration of HVBFS has been analyzed at late stage. Considering the improvement of the early hydration of HVBFS, it is necessary that the content of OPC is about 20 to 30％ in HVBFS cement with 6,000 fineness of BFS, when 4,000 fineness of BFS is used, the content of OPC is about 30％ or the replacement of LSP to HVBFS cement. By adding of 20％ LSP, the early hydration of BFS is accelerated in HVBFS cement and the late hydration of BFS is not changed compared with the BFS reaction in HVBFS cement without LSP. The reaction of BFS is accelerated by using of 6,000 fineness of BFS and the reduction of anhydrite contents in HVBFS cement. Another factor in mix-proportion of HVBFS cement has little effect on the hydration of BFS at late stage.

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Reducing emission of CO₂ is the most important problem in the cement industry. Recently, high volume blast furnace slag cement（HVBFSC）has been noted for environmental loading reduction.
This paper discusses the adsorption and the dispersion mechanism of superplastisizer（SP）on HVBFSC.
Using a control stress type rheometer（rotational cylinder viscometer）, the viscosity of the suspension was measured to estimate the apparent viscosity at a shear stress of 200 Pa. The absorbed amount of polymer calculated from the concentrations of the polymer in the initial solution and the liquid phase. The unabsorbed polymer concentration was measured by carbon analysis using a total organic carbon analyzer（TOC）.
In the case of SP having large amount of functional groups, SP is adsorbed on the surface of BFS and OPC in HVBFSC and disperse them increasing fluidity of the cement paste. On the other hand, in the case of SP having small amount of functional groups, SP is adsorbed on the surface of BGS in HVBFSC. Therefore the increase of fluidity of the cement paste largely depends on the increase of fluidity of BFS, resulting lower fluidity compared to SP with large amount of functional groups. Addition of the latter SP by large amount can achieve enough fluidity. It is considered that the higher concentration of residual polymer prevents the decrease of fluidity of HVBFSC.

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The cement industry is a major generator of CO₂ gas by cement production. Replacing cement by blast-furnace slag is an effective method for reducing CO₂ gas exhaust. In this study we investigated the reaction and the microstructure of hydrated products when used high volume blast-furnace slag. We analyzed products produced from Blast-Furnace Slag（BFS）-Anhydrate（CS）-Ordinary Portland Cement（OPC）and lime stone powder（LSP）. The hydration reaction and immobilization mechanism of Cr（Ⅵ）in this type of cement were analyzed by X-ray diffraction and Scanning Electron Microscope, and when chemical analysis at water solution was determined by inductively-coupled plasma optical emission spectrometry. The mainly hydrated cement products are ettringite, monosulfate, and Ca（OH）₂. When the cement immobilizes Cr（Ⅵ）, monosulfate is usually formed. However, by adding LSP to the samples it changes monosulfate to monocarbonate or hemicarbonate. Monocarbonate and hemicarbonate has not revealed the ability to immobilize Cr（Ⅵ）. We propose that hemicarbonate has sufficient space to incorporate Cr（Ⅵ）ions into its structure more so than that of monocarbonate.

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The blended cement has been positively used in Japan, because of environmental problems and useful recycling of industrial wastes have been considered in recent years.
Not only blast-furnace slags known as hydraulic materials, but also fly-ash and fumed silica that have character of pozzolanic activity are effectively used. The pozzolanic activity is generally confirmed by quantitative measurement of calcium hydroxide consumed in hydrated binder mixtures. On the other hand, the calcium silicate hydrates（C-S-H）value generated by the hydration estimated from the residual values, in which unhydrous cement clinker and crystalline hydrates are subtracted from whole hydrates, is not accurate.
The authors have reported a study of changes in silicate anion structures of hydraulic binders, such as ordinary Portland cement（OPC）and pulverized blast furnace slags, during hydration using trimethylsililation（TMS）method. In this study, the pozzolanic reaction of the pastes mixed with fly-ash and calcium hydroxide are studied in terms of mechanisms of their influences on silicate anion structures by use of TMS method. We clarified difference between the reaction of hydraulic materials such as OPC / blast-furnace slags and of pozzolanic materials such as fly-ash from analytical results of silicate anion structures of C-S-H in detail. Furthermore, the activation of pozzolanic reaction of fly-ash with heating is related to the formation of C-S-H.

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This paper investigates the intermediate phase（IP）existing as the precursor for the Calcium Silicate Hydrate（C-S-H）, that is the main component and directly affects physical properties of cementitious materials. Although many researches in connection with cement hydration have been carried out, most of them focus on not formation of C-S-H but the dissolution of cementitious minerals. Previous researches showed that the structure of C-S-H is not formed as soon as dissolution of cementitious minerals, dissolved sementitious minerals once become IP as the precursor for the C-S-H and they transpose to C-S-H gradually. It also reported that IP remains even long aged cementitious materials. Therefore transition of IP needs to be considered quantitatively and qualitatively. Bellmann et. al^5） already proposed the method to measure the amount of IP by using ¹H-²⁹Si CP MAS-NMR, but it requires more than 3 weeks to measure only one sample. Thus, it is needed to establish a simplified method for quantification of IP. In this research, three procedures were performed to establish a simplified method and to measure transition of IP；First, the dissolution degrees of cementitious minerals were measured by X-Ray Diffraction（XRD）/Rietveld analysis. Second, the polymerization degrees of silicates were measured by ²⁹Si MAS-NMR. Finally, the amounts of IP were quantified by the difference of the dissolution and polymerization degrees. ²⁹Si MAS-NMR requires about 20 hours to measure one sample which is about only 3％ of measuring time of previous method. As the result, after mixing water and cement, the amount of IP increased with the hydration. The amount of HM reached up to 30％ of all silicate anions when the dissolution degree of calcium silicates was 40％. However, even in the long period, about 5％ of HM still existed. The temperature dependencies of the IP hydration were also discussed. The amount of IP for the sample curing at higher temperature was less than other temperatures, because the curing at higher temperature promoted the phase transition from IP to C-S-H in the short period. However the C-S-H hydrated at higher temperature might form denser structure and it prevented the hydration on the long period. It might be possible to promote the hydration by curing at appropriate temperature and maintaining more amount of HM.

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Chloride induced steel corrosion is the greatest durability problem in the reinforced concrete structures exposed to marine environment. Therefore, it is important to elucidate the mechanism of chloride transport into cementitious materials. Both ion-ion and ion-solid interactions are influencing on the chloride transport into cementitious materials. Chloride can interact with cement hydrates chemically as well as physically. The electrostatic interaction of chloride on the surface of calcium silicate hydrate（C-S-H）, the main hydration product of cementitious materials, can be considered as the physical adsorption. It has been proved that the physical adsorption of chloride on C-S-H dominates its transport into matured cement paste. However, the surface electrical properties of C-S-H have not properly determined yet. Thus, the main purpose of this study is to determine the amount of surface site on C-S-H and its associated equilibrium constants. The objectives are achieved through experimental and modeling techniques. A two-layer surface complexation model was used to determine the surface site density of C-S-H（with Ca/Si of 0.6, 0.83 and 1.0）and the equilibrium constant values for dissociation of silanol sites and adsorption of calcium on silanol sites. The parameters are derived by fitting the titration and calcium adsorption experimental data to the model results. It can be inferred that the estimated parameters in this study will provide insight into the prediction of adsorption and diffusion of not only chloride but also other ions in cementitious materials.

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In order to obtain an insight about the mechanisms of Shrinking Reduction Agent（SRA）in cementitious materials, deuterium（²H or D）quadrupolar echo NMR spectra, deuterium relaxation time τ₁, rotational correlation time τ_c and rotational diffusion coefficient were obtained from white portland cement and D₂O mixture at different drying conditions such as RH 11, 33 and 60% for 28days. The result showed that（1）the mobility and diffusivity of water molecules in capillary decreased by adding SRA, however, these decrease might not enough to prevent water molecules in capillary from vaporing and（2）SRA exists more larger pore than large gel pore in Calcium Silicate Hydrate（C-S-H）which is the main component of harden cement paste. Thus, SRA does not exist in inter layer and small gel pore which is smaller pore than large gel pore in C-S-H. The result also support the hypothesis study about the mechanisms of SRA which proposed that SRA support the structure of large gel pore and prevent C-S-H from shrinking.

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For the creation of the recycling society, it is necessary to figure out the hydration behavior of the aluminate phase in detail. To achieve the objective, hydration of the aluminate phase in the cement paste using white cement was investigated. Especially, calcium aluminate hydrate（C-A-H）which is an amorphous phase was examined in this research. Judging from the mass balance of aluminum which it considered from results of Powder X-ray Diffraction（XRD）/Rietveld analysis, Thermogravimetry-Differential Thermal Analysis（TG-DTA）and Differential Scanning calorimetry（DSC）, it was confirmed that quantity of aluminum present in C-A-H increased in case of high curing temperature. In addition, when it applied a kinetic model of calcium aluminate cement of the past research to aluminate phase in the cement paste, it was shown that application to the first peak was possible and reaction coefficients has temperature dependency. On the other hand, there was room of examination about application to the second and third peaks. Furthermore, it was guessed that the stagnation of the hydration of the first peak was caused by the fact that C-A-H was generated by the aluminate phase outer layer, and inhibition of mass transfer is caused by amount of C-A-H increased in case of high curing temperature.

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Cements and admixtures have their specific colors. Within a particular factory or construction site, kinds of the cement used are limited；therefore, it is possible to identify the types of the cements and/or to determine the contamination of them by simply measuring the color of cements. In the present work, we have developed a portable and generic tristimulus colorimeter for field use and it was applied to the identification of cements. As the results, four kinds of cements, such as ordinary portland cement, moderate-heat portland cement, portland blast-furnace slag cement, and ecocement could be clearly discriminated by this colorimeter. Furthermore, additives such as blast-furnace slag and limestone were successfully determined by the colorimeter with 5％ precision. The time required to measure the color of cement samples is only 5min and its rapidity and simple operation are highly suitable for the quality control of cement on site.

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Decreasing the burning temperature of cement clinkers leads to a rational reduction of CO₂ emitted from the cement industries. This study examines the use of CaF₂ and CaSO₄ as a mineralizer or flux. It was possible to reduce the burning temperature 100℃ below that of the current process（1450℃）by controlling the fluorine and sulfur trioxide in the clinker. The setting and hardening properties of the low－temperature cement equal those of ordinary Portland cement. It was also found that the coating effect of additional mineralizer components on the preheater was insignificant.

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Cement industry has much contributed to recycling of waste material and by-product, through its characteristics such as no generation of secondary waste material and high temperature process. Waste material and by-product have been diversified year by year according to the increase of their recycling amount. As dealing with diversified wastes, it has become more important to control kiln condition in order to maintain clinker quality. Though the indexes such as an electric load factor of the kiln and gas temperature would be useful to control the kiln condition, it is difficult to measure the temperature of the highest temperature region in the kiln directly, which would be the most important factor to control clinker sintering. In this study as clinker analysis method, it became clear that the porosity of clinker depends on sintering temperature rather than sintering retention time. Therefore, it was able to be estimated that the porosity of clinker which had been sintered before would be influenced by re-sintering temperature. As a result, it was found that the porosity ratio of clinker was changed in case the re-sintering temperature was over the previous sintering temperature. Thus, it is able to be considered that the estimation of sintered temperature of clinker would be possible in this method.

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The expansive additive had been developed to control the cracking due to the volume change with its self-expansion capacity. The expansive concrete could be prospected for a reliable countermeasure for the cracking if the method of expansive strain prediction is established. However, no universal agreement exists concerning fundamental mechanism leading to the effective expansive strain at different temperatures. This paper presents the relationship between expansive strain and hydration products of expansive mortar at 20, 30, 50℃. The temperature dependency of expansive mortar was confirmed at 20, 30, 50℃. It was observed that ettringite（AFt）increased at 20, 30℃, in the meanwhile, was very small AFt after 1day at 50℃ by using DSC and SEM. Hence, it was suggested that the hydration of AFt is affected by temperature history.

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C-S-H is a dominant hydration product of cementitious materials. Therefore, its chemical composition and physical properties affect the properties of concrete. However, the composition and the properties of C-S-H, and the relation between both have not been completely clarified. In order to evaluate the concrete performance accurately, the physical properties of concrete should be evaluated accuracy. Therefore, it is important to clarify the chemical composition and the physical properties of C-S-H.
The purpose of this study is to clarify the chemical composition（the C/S ratio and H/S ratio）and specific surface area of C-S-H. The C/S ratio, the H/S ratio and the specific surface area of C-S-H were estimated by using synthesized C-S-H and C-S-H generated from synthesized alite paste. In addition, the specific surface area of calcium hydroxide and calcium aluminate hydrates were estimated by synthesized hydration products. Furthermore, the specific surface area of hardened cement paste was measured.
From the experimental results, the H/S ratio of C-S-H under each relative humidity is proportional to the C/S ratio independent of the mix proportion and curing temperature. From these results, the relation equation between the C/S ratio and specific surface area of C-S-H is proposed. Moreover, the specific surface area of hardened cement pastes can be estimated by the amount of hydration products and each specific surface area of hydration products.

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In this study, the influence of constraint condition on micro-pore structure and oxygen diffusion coefficient of expansive mortars was investigated. In the experiment, mortar specimens having various amounts of expansive additive and constraint conditions were prepared. After that, the micro-pore structure, oxygen diffusion coefficient and amount of expansion in each specimen was measured and the influence of constraint conditions was discussed. As a result, the amount of a micor-pore continuity of the expansive mortars decreases when restricting, and the oxygen diffusion coefficient have become small along with that. Moreover, the evaluation of the mass transport resistance of the expansive mortars by the restraint became possible by method based on the concept of the work.

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This paper reports the results of an investigation of effects steam heat-curing cycles on hydration of fly ash cement for the raising efficiency of precast concrete production. The steam heat-curing conditions for the investigation were varied by changing the preset curing time（time before steam curing）, temperature rise rate, maximum temperature retention time, temperature reduction rate. The Compression tests were conducted on mortars made using fly ash cement under steam heat-curing conditions. The hydrate composition was measured by thermo-gravimetric/differential thermal analyzer（TG-DTA）, selective dissolution method and X-ray diffraction（XRD）Rietveld method to clarify the influence of steam heat-curing on fly ash cement hydration. The steam heat-curing of cement incorporating fly ash accelerates the pozzolanic reaction and results in considerable increase in the one-day compressive strength. The effect of temperature reduction rate predominates over other factors of steam heat-curing condition. The optimum conditions of steam heat-curing cycles that shorten the length of the precast concrete manufacturing process within the investigated range appears to be a 4 hours consisting of a preset curing time 0.5 hour, temperature rise rate 30℃/h, maximum temperature and its retention time at 65℃ for 2 hours, quick cooling.

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Many studies on effective uses of industrial by-products such as blast furnace slag and fly ash have been carried out. In the future, the application of more kinds of wastes to concrete will be expected. These wastes, however, may contain heavy metals. There is a possibility of heavy metal leaching from concrete containing wastes. Although there are some test methods for evaluating heavy metal leaching, it is not clear whether or not they are available to concrete. A test method of heavy metal leaching from concrete that is a mass body should be needed. Also, when concrete is used for a very long term, heavy metal ions may leach. In this study, to understand the primary leaching behavior of the heavy metal from concrete structures, adsorption and desorption tests and a tank leaching test were performed. Lead was focused on as a heavy metal. As a result, much larger lead ions were desorbed after adsorption when calcium chloride solution was used as a solvent rather than pure water, sodium chloride solution, potassium chloride solution and lithium chloride solution. The results of the tank leaching test also showed that lead ions were leached much more from the specimen containing lead ions when the specimen was immersed in calcium chloride solution than in pure water.

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In this contribution, velocities of elastic wave and shear wave were obtained by ultrasonic pulse method with hardening cement paste and mortar whose water to cement ratio was 0.30, 0.40 and 0.55. And four classes（cement paste, 20%, 40%, 60%）of aggregate volume fraction ratio were prepared in each water to cement ratios. Then, Poisson’s ratios and dynamic elasticity were calculated from experimental results of elastic wave, shear wave and bulk density at predefined concrete age. As a result, steep reduction of Poisson’s ratio was observed in early age in all specimens, however, decreasing ratio was different from each aggregate volume fraction. And it was reported that this time dependent changes of Poisson’s ratio made an influence to accuracy of composite model for predicting the dynamic elasticity in the case of the range over 40% volume fraction of aggregate. In that case, the estimated values were improved by taking time dependent changes of Poisson’s ratio into consideration. On the other hand, the estimated value by Hashin - Hansen model of mortar whose volume fraction of aggregate was 60% showed much higher value than measuring. And this difference was considered to be occurred due to large amount of void content than that of lower volume fraction of aggregate.

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It is known that the evaluation of volume change of hardened cement paste is controlled the hydration force, which derived from the potential of hydroxyl group. And then, for the evaluation of volume change due to hardened cement paste drying, specific surface area of calcium silicate hydrate in the hardened cement paste, which affects statistical adsorption vapor thickness in the hardened cement paste, is focused. The synthesized calcium silicate hydrate（synthesized C-S-H）, which calcium to silicate molar ratio is 0.9, 1.1, 1.3, 1.5, is prepared. The specific surface area of each C-S-H, which pre-treated under degased and each temperature（30degC, 105degC, 150degC）, is measured by 20degC vapor adsorption isotherm and B.E.T theory. The H₂O/Si molar ratio of each C-S-H, which humidificated under each relative humidity（0％RH, 60％RH, 95％RH）, are measured by Thermal Gravity Analysis. Based on thermodynamic model of silanol group on the C-S-H by Nonat, the unit model of C-S-H, which has four silanol group（two variable -SiOH, a -SiOH, a -SiOCaOH） is proposed. the number of water molecule, which adsorbs on each silanol groups, is identified and the specific surface area model of C-S-H in adsorption process are proposed. The proposed model can predict the specific surface area of various C-S-H, which has various Ca/Si molar ratio or pretreated each temperature drying condition.

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This study is concerned with structure change of the calcium silicate hydrates（C-S-H）, which is the main component of hydrated cement, under environmental condition changes. It is known that C-S-H is amorphous and there are many problems about its structure. Jennings^4） proposed the gel model for the nanostructure of C-S-H, which shows that the aggregation of the globules that is the minimum unit of C-S-H forms nano-structure with various size pore. Therefore it is necessary to measure the pore size distribution of C-S-H and globule structure to understand C-S-H structure. For instance Mercury Intrusion Porosimetry and gas adsorption are the widely-applied techniques to measure the pore structure. However their result of the pore structure of hardened cement paste is significantly affected by the prerequisitie drying. The purpose of this study is to clear that the structural change of C-S-H avoiding effects of the extreamly drying to prepare the samples.
In this study three environmental conditions were set：specimen were left at 50℃ in air for drying（D50）, at 50℃ in air for drying and at 20℃ in water for wetting（D50W20）and at 20℃ in water for wetting（W20）. And two instruments were used for determination of C-S-H structure. The first is solid-state ²⁹Si MAS NMR to measure the mean length of silicate chain and the chemical environment of silicates such as neighbor ions. The second is thermporometry with low temperature differential scanning calorimeter（DSC）to measure the pore size distribution. In DSC measurement the pore size distribution is measured according to the frozen temperature of water in pore, thus it is possible to avoid the destroy of C-S-H structure.
As a result of DSC, for the W20 samples C-S-H structure became dense and cumulative pore volume decreased. For the D50 and the D50W20 sample, the pore volume became porous and cumulative pore volume increased. It was shown that the structural changes of C-S-H caused under drying condition.
As a result of ²⁹Si MAS NMR, for the W20 samples the mean length of silicate chain didn’t change. On the other hand, for the D50 and the D50W20 samples the mean length of silicate chain increased. It is considered the increase of mean length of silicate chain makes globule dense. It was shown that drying condition made the C-S-H localy dense and the bulk density of C-S-H increased.

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The mass transport properties and the durability of cement concrete are controlled by their microstructure which includes several different kinds of pores, and thus the characterization of the shape and size distribution of pore is important for prediction of durability of cement concrete. This paper describes the quantitative determination of pore-size distribution of microstructure in hardened cement paste by thermoporometry. The conventional determination method for pore-size distribution, such as nitrogen gas adsorption（NGA）and mercury intrusion porosimetry（MIP）have a disadvantage that the sample must be dried. The drying results in significant alteration of the smaller pores, and this has led to doubt about the validity of NGA and MIP data. In contrast, thermoporometry does not require the drying of sample, so it seems to be an ideal method to quantify the microstructure of hardened cement pastes. Thermoporometry is based on a thermodynamic equilibrium type from latent heat - temperature relations to occur with freeze, fusion of the water in a pore. Low-temperature scanning calorimetry is used to monitor latent heat associated with freezing of the pore water and melting of the ice in pore. The results of thermoporometry for MCM-41 indicates that considering the effect of non-freeze water on the thermodynamic conditions of liquid and solid transformation, the accurate prediction equation of the size and shape of finer pore, of which radius few nano-meters or less, can be given. The thermoporometry study for hardened cement pastes shows that the pore structure in hardened cement pastes is ink-bottle type with two different entry pores. Furthermore, MIP destroys the microstructure of hydration hydrates, so it is difficult to quantify the size of entry pore.

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It is very important to predict the deterioration of concrete that is used for a storage container of the radioactive waste. So it is necessary to comprehend the deterioration of cement based materials associated with calcium leaching by contact with the ground water for the super long term. However, there are not many knowledge about the diffusion performance of deterioration of calcium silicate hydrate associated with calcium leaching. Therefore, this study focused on the degradation of calcium silicate hydrate with calcium leaching, in order to gain the knowledge of the transport properties of calcium silicate hydrate. As a result, there was the correlative relationship between porosity in calcium silicate hydrate and the diffusion coefficient of chloride ion of calcium silicate hydrate associated with calcium leaching. Also, we attempted to estimate the diffusion coefficient of chloride ion in the calcium leached hardened cement paste from plain hardened cement pastes, with the deterioration of calcium silicate hydrate and calcium hydroxide. And there was no difference between estimated value of the diffusion coefficient and measured one. Therefore, it was shown that it was important to consider the leaching of calcium hydroxide and the degradation of calcium silicate hydrate in order to predict of the transport properties of cement based materials.

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This study was conducted to investigate the mechanism of sulfate attack with MgSO₄ solution of cementitious materials containing Ordinary Portland Cement（OPC）with Blast Furnace Slag（BFS）, anhydrite（AH：CaSO₄）and lime stone powder（LSP：mostly CaCO₃）, and to design a cementitious material with improved sulfate resistance. This study also focused on the influence of adding BFS, AH and LSP on MgSO₄ resistance of OPC paste specimens. The sulfate resistance was improved by adding BFS, AH and LSP；the best MgSO₄ resistance was found for BFS/OPC ratio＝70：30 with AH 5-10％-LSP 5-20％. It was concluded that（a）the amounts of CH, responsible for both expansion and shrinkage, could be decreased with increasing the BFS replacement ratio（especially by adding 70％ BFS）（b）a large amount of ettringite instead of monosulfate was produced before immersion in sulfate solution when AH was added and（c）adding LSP resulted in production of monocarbonate, which was stable in sulfate solution, instead of unstable monosulfate.

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There is a report that the crack resistance of concrete improves by contents of the alkali in cement few. When it mixes with the cement paste, an artificial zeolite captures the alkali ion such as Na and K ions in cement. Accordingly, the purpose of this research is to examine the crack resistance by an observation of the change in the density of the alkali ion in the cement paste that mixes an artificial zeolite with the ordinary portland cement, and various experiments. Especially, it pays attention to the ion exchange capacity for the zeolite to capture Na and K ion. In addition, the influence that the zeolite gives to the cement paste is confirmed by measuring of the hydration rate and measuring pore size distribution. As a result, it was able to be confirmed that the alkaline metal in the paste was captured when the zeolite was mixed, and the crack resistance improved. Moreover, it was able to be confirmed that the hydration rate rose when the zeolite was mixed, and the pore structure shifted to the small diameter side. However, it is thought that not only the influence of the alkaline metal but also the influence of the product quality etc. of the pore structure and the hydration influences the crack resistance combining.

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Aiming at reducing environmental burdens such as greenhouse gas emission, protland blast-furnace slag cement partially replaced with limestone powder, at slag content of 40 percent, was studied. When the base cement was replaced with a limestone powder, with a fineness of 3,500 and 5,480cm²/g, for 10 to 30 percent, resulting mortar showed equivalent properties, fluidity and strength, with those using current portland blast-furnace slag cement. Because clinker content in produced mortar is less than that of the currently available cement, use of the newly developed cement could lead to a reduction of cement-originated CO₂ gas emission in the concrete sector.

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The use of industrial waste as a raw material for the production of cement is expanding. However, it causes increased C₃A content in cement. On the other hand, in order to prevent thermal cracking of concrete, it will become increasingly important to control the adiabatic temperature rise. The hydration property under adiabatic temperature rise has hardly researched experimentally. In this study, for high C₃A cement cured under adiabatic temperature rise, the ratio of reaction of each clinker mineral was compared with that under the normal temperature cure, and the hydration property was evaluated. These results indicated that heat of hydration of cement used clinker with 12％ C₃A was higher than that of cement used clinker with 10％ C₃A in JIS R5203. On the other hand, the ultimate adiabatic temperature rise of these samples was not very different, and both of the heat of hydration calculated from the temperature rise was similar. Then the rate of reaction of each clinker mineral was evaluated. These results indicated that the rate of reaction of C₃A cured under adiabatic temperature rise decreased compared with that the under normal temperature cure. In addition, when C₃A content in clinker increased, the rate of the reaction was lower. Therefore, it was thought that the adiabatic temperature of the cement used clinker with 12％ of C₃A did not rise significantly.

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Using ettringite-lime composite expansive admixture jointly with various types of shrinkage reducers（SRs）, the effects of SR types on the physical properties of mortar were investigated. Among various types of SRs, some SRs increased expansive strain and others slightly decreased expansive strain compared with the single use of expansive admixture. Difference in expansive strain occurred during 1-3 days, and in the range of additive ratio between 0-2％, the higher the additive ratio, the larger the difference in expansion strain was. SRs that increased expansive strain gave minor effect on the hydration reaction of expansive admixture, but moderately suppressed the hydration reaction of cement. Possibility is suggested that these SRs prolonged the effective expansion period capable of introducing expansive strain, resulting in increment of expansive strain. In all SRs, dry shrinkage strain become smaller compared with the single use of expansive admixture, showing further effect on the shrinkage suppression of mortal mixed with expansive admixture.

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As various types of industrial wastes are used for materials and fuels in cement industry, it is expected minor elements would be derived from these wastes. It had been studied various minor elements in clinker would influence to mineral composition of clinker and properties of cement. In this study, we investigated the influence of titanium oxide in clinker on the mineral composition of clinker and the properties of cement. We prepared eleven kinds of clinkers in a laboratory, changing titanium oxide content and mineral composition of clinker respectively. Some clinkers have same mineral composition estimated by Bogue equation but have different amount of titanium oxide as a minor element. Other clinkers have different mineral composition estimated by Bogue equation but have same amount of titanium oxide as a miner element. As a result of XRD Rietveld analysis, we identified titanium oxide in clinker influenced the mineral compositions of clinker and also influenced the properties of cement, namely, the titanium oxide content was related proportionally to the mineral composition of clinker estimated by XRD Rietveld analysis and the properties of cement. For silicates phase, alite decreased and belite increased with increasing titanium oxide content. For interstitial phase, aluminate phase increased and ferrite phase decreased with increasing of titanium oxide content in clinker. These trends were similar even in different mineral composition of clinker estimated by Bogue equation. It could be find the property of early hydration and fluidity depended on the amount of aluminate phase estimated by XRD Rietveld analysis, and the property of strength depended on the amount of alite estimated by XRD Rietveld analysis.

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In this study, the applicability of the newly proposed simplified estimation method of expansive cement concrete with cylindrical light-weight steel mold was analyzed based on the concept of the mechanical work. When the expansive strain of the concrete was around 700×10^－6 or less, the linear relationship between the circumferential strain of the cylindrical specimen for the simplified method and the uniaxial strain of the standard specimen was observed in the experiments. Here, the circumferential strain was almost equivalent to the uniaxial strain or a little bit smaller than the uniaxial strain. These relationships could be explained by the concept of the mechanical work considering the effect of restraint condition and curing condition. Then, it was shown that the uniaxial strain of the standard specimen can be quantitatively predicted from the circumferential strain of the simplified method. When the expansive strain was larger than 700×10^－6, the circumferential strain became much larger than the uniaxial strain due to the yielding of the cylindrical steel mold.

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Passive thermography using solar radiation is efficient for internal diagnosis of concrete by means of passive thermography. However, the expected surface temperature of concrete varies greatly with weather conditions and internal defect state, and therefore appropriate judgment of parameters including diagnosis timing with regard to weather conditions is required to avoid misdiagnosis. Thus in this study, we carried out experiments and thermal conductivity analyses to investigate the effects of moisture conditions on temperature rise in normal and defective portions of a concrete surface. As the result, we clarified that even though standing water is observed on a concrete surface, the temperature rises sharply if the surface dries before solar noon, and that heat storage increases due to moisture in the surface portion, thus aiding diagnosis.

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In the present paper, we examine a countermeasure method for nondestructive quality evaluation of surface concrete by using air permeability tests, which have a problem such as susceptibility to moisture content in concrete. The tendency of air permeability to increase with age of concrete until at least 6 months was shown on the exposure tests of concrete specimens with different W/C and demolding age to atmosphere under 20℃ and 60％rh. Clarifying insufficiency of the previous suggested method by Torrent et.al., we have proposed an original method considering the moisture content dependent of air permeability.

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The main cause of cracks in reinforced concrete is drying shrinkage. Therefore, shrinkage-reducing admixture is used. The Architectural Institute of Japan has defined a shrinkage prediction equation in “Recommendations for Practice of Crack Control in Reinforced Concrete Buildings（Design and Construction）（2006）.” The equation considers external factors such as the volume?surface-area ratio and relative humidity, in addition to internal factors such as materials and mix proportions of concrete. However, it is necessary to confirm the validity of this equation by performing experiments.
In this study, an expansive additive and a shrinkage-reducing agent were used in the experiments. Using the drying-shrinkage prediction equation, the coefficient of mix proportion of concrete（K₁）, coefficient of concrete age at initiation of drying（K₂）, and coefficient of relative humidity（K₃）were quantified. Experimental results showed that the shrinkage-reducing agent had a greater influence on drying shrinkage than the expansive additive. In addition, the coefficient of mix proportion of concrete（K₁）was evaluated by effect of the type of admixture（γ₃）. Therefore, it verified to focusing to γ₃. In addition, the influence of the shrinkage-reducing admixture was evaluated using the drying-shrinkage prediction equation. Moreover, the individual influences of the expansive additive and the shrinkage-reducing agent, as well as their combined influence, were quantified.

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The unit water content in a fresh concrete is one of the most important factors that control a concrete quality. In this study, it aimed at the development of the measurement method of unit water content by inserting a cylinder shape neutron water meter in the fresh concrete in the drum of agitator track. When developing, the influence of the agitating condition of the drum, the necessity of the compensation by the gamma-ray densimeter and time necessary for the measurement was verified by measuring fresh concrete that set the unit water content in the drum of the agitator track to five levels. As a result, it was confirmed that should make the drum a low-speed agitating condition, to have not always be necessary the compensation by the gamma-ray densimeter, should measure for two minutes or more. In addition, a good working efficiency was confirmed by the real construction.

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In this study, communication function of Rf tag embedded in the concrete and physical properties of concrete specimen including RF tag were evaluated by experiments. It was found that the influence of water immersion into the inside of the tags are the main cause of lowering the communication function. Check of the long term water resistance performance of tags in the concrete before use is very important.
Compressive strength of cylinder specimen embedded different size of RF tags was measured. It was found that compressive strength was affected by size and position of RF tag in concrete. While, it was clarified that compressive strength did not decrease when the RF tag size was less than

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In this study, X-ray fluorescence analysis of silica fume using pressing forming sample was studied experimentally in order to obtain some basic data about the sample preparation method, which is one of the most important problems, toward the introduction of X-ray fluorescence analysis method to chemical analysis of silica fume. As a result, X-ray fluorescence analysis of silica fume was found to be applicable to chemical analysis by using samples prepared by pressing forming under the suitable sample preparation conditions, without influences of volatile components which are problems in the glass beads sample.

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The purpose of this study is to clarify the influence of quality of coarse aggregate on drying shrinkage of concrete. The drying shrinkage test of concrete by using seven kinds of coarse aggregate having different qualities were examined. As a result, the drying shrinkage changed with the kind of coarse aggregate, and the correlatively between the drying shrinkage of concrete and aggregate itself was very high. As a whole, the drying shrinkage of concrete tends to increase as the water absorption and the total pore volume of coarse aggregate increased. However, the drying shrinkage of concrete by using sand gravel increased although the water absorption and the total pore volume of sand gravel was relatively small. Furthermore, the relationship between micro-pore structure and shrinkage of aggregate was examined by using SEM observation of the mirror polished surface of aggregate.

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Melting and solidifying refuse incineration ash is performed in many local governments from the viewpoint of volume reduction and detoxifying of municipal solid waste. Many researches have been conducted to make use of melt-solidified slag, byproduct of the melting and solidifying process, as fine aggregate for concrete. Although melt-solidified slag is specified in JIS A 5031, its range of application is limited due to lacking in actual usage examples and knowledge about long-term stability. Widening the range of application of melt-solidified slag will greatly contribute to prolongation of residual year of waste disposal site, so it is important to continue to collect a large variety of data. Furthermore, properties of concrete with melt-solidified slag aggregate will be different by melting furnace type and origin of garbage, so it is necessary to accumulate data considering area characteristic. In this study, fundamental investigation was conducted to apply melt-solidified slag produced in the center part of Miyazaki prefecture to concrete as fine aggregate. As results of laboratory experiments, it was cleared that fresh properties, mechanical properties and durability of the concrete using the melt-solidified slag is equal to or more than those of normal concrete, under the condition that slag replacement ratio is less than 25％. It was also indicated that using fly ash remarkably improves the quality of concrete with high slag replacement ratio. Furthermore, two kinds of precast concrete products were manufactured on trial at the factory. It was confirmed that the manufactured products has no problem in load bearing ability and environmental impact, under the condition that slag replacement ratio is less than 30％.

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The internal curing is one of the effective methods to prevent autogenous shrinkage in early age concrete. In this method, water-retentive particles are used as internal reservoirs to supply water to surrounding cement paste matrix. Absorbent particles such as lightweight aggregate, recycled aggregate and superabsorbent polymer are considered promising materials for the internal source of water. However, there are few recent reports on the reduction of autogenous shrinkage for cement based materials by adding natural fiber. The objective of this study was to determine how the early-age shrinkage behavior of cement based materials is affected by the addition of saturated jute fibers under sealed condition. The cement pastes specimens had a water cement ratio of 0.25. The fiber used was jute fiber of 6mm length. Volume percent of fiber contents were 0, 0.5, 1.0, 2.0％, respectively. Straw-like structures in jute fiber was observed on the photograph obtained by a scanning electron microscope（SEM）. Additions of 0.5％ and 1.0％ of jute fiber by volume of cement paste led to 12％, 36％, reduction in autogenous shrinkage strain at 8 days, respectively. Whereas, decrease of compressive strength were small. These results show availability of jute fibers for internal curing material.

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Carbonation is known as a deleterious phenomenon for concrete structures. On the other hand, however, it can have some positive consequences to concrete. It results in increases in surface hardness and strength of concrete so that the surface zone of carbonated concrete acts as a protective layer against penetration of harmful species. Furthermore, carbonation has been revisited recently because it is a fundamental function of self-healing in concrete. Such a positive effect of carbonation on properties of concrete is accompanied by changes in porosity and pore size distribution of the surface zone of concrete. In this study, in order to investigate changes in permeability due to carbonation at early ages, the electrical conductivity test and the SEM-BSE image analysis were carried out for cement pastes and concretes that were exposed to an accelerated carbonation condition. The pastes specimens were subjected to the carbonation environment immediately after demolding. The concrete specimens were stressed until the tensile stress/strength ratio of 50％ at 7days. Then, those damaged specimens were cured under the accelerated condition. When they were exposed to the accelerated carbonation at early ages, loss of water was reduced. Degrees of hydration of cement in the carbonated specimens were comparable to those in specimens cured continuously in water. Electrical conductivities of the cement pastes and the damaged concrete were also comparable to those cured in water. Dense surface zone formed by carbonation prevents water from evaporating even in a relatively dry condition. This led to further hydration so that the porosity was decreased and the induced microcracks were healed.

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Regarding blast-furnace slag concrete subjected to high temperature history of massive concrete, cracking strength under external restraint and direct tensile strength under no external restraint was compared. Analysis of microcracking by AE method was also conducted. Cracking strength under external restraint was around 70％ of direct tensile strength of specimens without external restraint. We had already revealed that direct tensile strength of slag concrete subjected to high temperature history was decreased due to microscopic thermal stress, but it was confirmed that direct tensile strength was furthermore decreased by external restraint. AE analysis showed that under the effect of external restraint, AE with larger energy was observed when concrete was subjected to tensile stress. Under the effect of external restraint, larger number of shear type AE were observed. Shear type AE was generated when cracking was developed into the slipping along the boundary between aggregate and matrix. When larger AE energy and larger number of AE events were observed, cracking strength of restrained specimen was smaller. The larger extent of microcracking will lead to the reduction of cracking strength.

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Limestone aggregate has much powder because of weak resistant to abrasion. In case of using limestone with rich powder, the powder may affect several properties of concrete, such as fresh properties and strength development. The objective of this study is to investigate fundamental properties of concrete using limestone aggregate with rich powder, and to obtain the upper limit of powder volume for structural concrete. Some fundamental tests were conducted using limestone coarse aggregate with rich powder up to 30％. This paper reports adiabatic temperature rises of the concretes as well as fresh properties. In addition, the paper presents coefficients of thermal expansion of hardened concrete; and reports compressive and tensile strength developments. The test results indicate that concrete including the powder of 30％ has notable fresh properties, lower slump and air content. According to the simplified test using Styrofoam, the volume of limestone powder slightly affects the temperature rise at early age, but it hardly influences on the ultimate temperature rise of concrete. Furthermore, all limestone concretes used herein indicate lower coefficient of linear expansion than the coefficient of typical concrete. Strength of the concrete at early age tends to be improved by powder volume, especially splitting tensile strength develops significantly. The strength development, however, becomes negligible in over 20％ of the powder volume. Based on these test results, the upper limit of powder should be considered as 20％ of the aggregate.

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Recently, it is necessary to reduce CO₂ emissions in terms of environmental impact reduction. Concrete generates extremely large environmental impact. In material manufacturing, cement is a material that especially emits the largest amount of CO₂ among other materials of concrete. An effective means of reducing CO₂ is considered to replace a part of ordinary portland cement with fly ash and blast-furnace slag. However, concrete of high replacing rate of the admixture is considered to decrease strength development of concrete at an early age and increase autogenous shrinkage of concrete. Therefore, it is realistic for reducing CO₂ emissions to use versatile cement with relatively-low replacing rate of the admixture. In this study, low-carbon concrete using fly ash and blast-furnace slag for low water-cementitous material ratio（W/B＝0.30）have been measured on compressive strength, pore size distribution, autogenous shrinkage and resitance to shrinkage cracking. In addition, the effect of the reduction of CO₂ emissions in comparison to difference of the water-cementitous material ratio（W/B＝0.30 and 0.40）is verified. From the abovementioned test results, regardless of curing condition and the combination of the admixture replacing ratio, the compressive strength of concrete at the age of 91 days obtains the same performance of concrete without the admixture. Also, the effect of the reduction of CO₂ emissions is almost the same regardless of the water-cementitous material ratio. Furthermore, the concrete manufacturing of low environmental impact is the range of an appropriate water-cementitous material ratio.

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The self-hearing concrete targeted in this study is aiming to prevent leaking water from the concrete cracks. By using self-healing materials as admixture, the concrete is given a self-healing ability. The mechanism of self-healing phenomenon brought by the self-healing admixture used in this study is that the hydration of the low reaction activity cement is caused when water is supplied from the outside through the crack；the low reaction activity cement is main material of the self-healing admixture. In addition, it was able to improve the performance of the self-healing admixture by including short fiber and hydration control material. The short fiber has the effect of promoting extracting of the hydrate at concrete cracks. And the hydration control material controls an initial hydration reaction of the low reaction activity cement；as a result, the ability of the self-healing admixture is kept. As a performance assessment of the self-healing concrete, the water permeability test was executed at laboratory and outdoor. In the water permeability test, leaking water from the concrete cracks did not stop completely. Though, the width of crack has decreased by self-healing in early time of the water permeability test, and water permeability ratio decreased greatly, a similar tendency was seen in the laboratory and outdoor.

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We estimated the temperature cracking resistance by computer simulation method. In the results, early age strength of concrete using super low heat portland cement whose belite is not less than 70％, is lower than using low heat portland cement（L）whose belite is less than 60％. However 91 days strength of ultra low heat portland cement is equal to L. In addition adiabatic temperature rise of ultra low heat portland cement is lower than L. Therefore super low heat portland cement increases the temperature cracking resistance of mass concrete. However, when belite is above 70％, increasing of the temperature cracking resistance is not confirmed.

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This report was investigated about durability of concrete and corrosion of reinforcement bar of several RC specimens exposed to marine and atmosphere environment. As for cement, 3 kinds of portland cement and 7 kinds of blended cement were used. Blended cement mixed blast furnace slag or fly ash or Limestone powder. Exposure time was 10 years. As a result, compressive strength of each concrete has increased. However, the level of an increase of strength was different by the kind of cement and the exposure environment. Carbonation depth of concrete with blended cement was larger than that of portland cement. However, the resistance of corrosion due to the chloride induced deterioration of blended cement was very high compared with portland cement.

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This study aimed at investigating deterioration resistance of porous concrete, which is assumed to be utilized as a component for rooftop gardening, under dry-wet cyclic exposure. Experimental investigations were conducted regarding temporal change in compressive behavior（compressive strength, Young’s modulus, strain at compressive strength, and n value in the Popovics equation）of porous concrete under dry-wet cyclic accelerated exposure test, in which the temperature conditions were more severe and the drying conditions were more loose than those standardized by the Japan Concrete Institute. As a result, it was shown that the compressive behavior of porous concrete did not remarkably decline under dry-wet cyclic exposure for almost four years（1,457days）. However, it should be noted that the compressive behavior of porous concrete is more sensitive to experimental conditions than those of normal concrete, because of its structure in which the coarse aggregates are covered/bonded by thin cement paste phase.

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As regards efficient use of fly ash a measure is required. However, characteristics of concrete using blast-furnace slag cement and fly ash are less well understood. In this study, the examinations were carried out in order to the effects of drying shrinkage and equivalent characteristics of concrete using blast-furnace slag and fry ash. As a result, concrete using fly ash as fine aggregate comparable in drying shrinkage strain and crack breadth to using blast-furnace slag cement only. In Case of concrete using fly ash as cement were fewer cracks than blast-furnace slag cement. And can be effectively used for preventing chloride penetration into concrete, but cannot be effective for preventing more progress of the neutralization.

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The carbonation-suppressing effect of coating material for textured finish is essentially evaluated by the ratio of the coefficient of diffusion of the coating material for textured finish for textured finish to the coefficient of diffusion of concrete carbon dioxide. But it is difficult to measure the coefficient of diffusion of the coating material for textured finish. In this paper, a carbonation progress is simulated by using carbonation resistances which are calculated by results of an accelerated carbonation test and the measurement of air permeability coefficient. Core samples for an accelerated carbonation test were taken from a structure several decades old, with coating materials for textured finishes. And the prediction formula for the carbonation progress of concrete is used, in which the coefficient of diffusion of the coating material for textured finish increases and the carbonation resistance decreases with time. It is based on an analysis model expressing that carbon dioxide moves according to an approximation of a steady state of diffusion, reacts with calcium hydroxide and the carbonation progresses. As a result, the carbonation progress is able to be predicted, which is considered the deterioration of the coating material for textured finish in an existing concrete structure which had built before several decades.

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