Recently, basic oxygen furnace slag produced by a new steel-making process is supplied as powdered particles containing a high content of free lime. When this slag is used as a material for the base course of road, its unfavorable self-deterious property may become an important problem. It is considered that the addition of granulated blastfurnace slag, which is a porous and stable material, to the powdered basic oxygen furnace slag can improve both the strength and durability of compacted mixtures. This paper deals with the effective utilization of powdered basic oxygen furnace slag and granulated blastfurnace slag in road construction. The suitability of compacted mixtures of two slags was investigated utilizing such characteristics as resistance to immersion in water, compressive strength and CBR value. Reaction products and microstructural features of the compacted slag mixtures were also elucidated by DSC-TG analysis, X-ray diffraction analysis and SEM observations. From the results, it was made clear that the addition of granulated blastfurnace slag to powdered basic oxygen furnace slag increased the strength and reduced the expansion in immersion in water, and that the compacted slag mixtures fully satisfied the requirements of strength and durability for the base course of road.
Volcanic soils show many abnormal characteristics in engineering properties. High natural water content, change in consistency limit with initial water content, different behaviors for the disturbed and undisturbed states, and irreversibility in compaction curve are some of them. Young volcanic soils contain many amorphous clay minerals. The abnormal behaviors are supposed to originate from the allophane behavior. Therefore, all the engineering properties were investigated as function of allophane content in this study. The main results obtained are summarized as follows. (1) The natural water content, liquid limit and permeability increased linearly with increasing allophane content, while the residual strength decreased. (2) The degree of deviation in compaction curve for the sample by drying process from that by wetting process depended on the allophane content. (3) The dispersive effect by acid became more effective than that by alkali when the allophane content increased. (4) The pF curve shifted to the side of higher water content with increasing allophane content.
Recently how to utilize resources and how to preserve natural environment have become serious problems in Japan. The waste rock powder is an industrial by-product from crusher plants. Since almost no disposal has been done for it, it causes the pollution of air and water. It is significant to examine how to utilize the waste rock powder as a construction material. If this becomes possible, the problems of resource utilization and the environmental pollution can be solved simultaneously. One method to solve the problems is to use the waste rock powder for soil stabilization. The purpose of this study was to investigate the possibility of reutilizing the waste rock powder for a supplemental material of stabilization. Firstly the relationship between physical or chemical properties of the waste rock powder and the unconfined compressive strength of stabilized specimens was examined in detail. According to chemical analysis, it was clarified that the waste rock powder has fairly large specific surface area and contains a large amount of amorphous materials. The unconfined compressive strength of specimens stabilized with lime or cement was closely related to the specific surface area or the ratio of Al2O3/SiO2, even if the waste rock powder was used as a supplemental material. In conclusion, this rock powder is useful to increase the stabilizing effect on soils having a small amount of fine particles, and if it is used, it results in saving the cost by reducing the amount of lime or cement.
Considering the present situation of problems arising from the treatment and management of wastes, the possibility of utilizing certain types of industrial waste as construction materials has been investigated. In this study, the carbonated aluminated salts (CAS materials) were used as a hardening material to stabilize the following industrial wastes: an incinerated pulp ash, a stainless-steel slag (S-slag), and a fluidized bed combustion coal ash. In order to investigate hardening characteristics of the treated materials, measurements such as unconfined compression test, abrasion test, and durability test under repeated cycles of wetting and drying were carried out. X-ray diffraction analysis (XRD) and scanning electron microscope (SEM) observation were also performed to investigate their particular reactions. The results obtained by the experimental investigations have revealed that the addition of a certain amount of kaolin clay as a pre-mixed admixture to the raw materials considerably improve the hardening effect and durability of the materials. Furthermore, the contribution of CAS material on hardening reactions is substantially related to the mixing time or the consistency of the mixtures. It is considered that the hardened industrial wastes examined in this study can be applied as road and embankment materials.
The expansion of electric furnace reducing slag is delayed by its complex hydration. Before using the slag, it is necessary to stabilize the expansion property. Currently the reducing slag is used after aging for stabilization of expansion and judging its stability by the expansion ratio based on the standard expansion test results. Because of delayed expansion, a long time of aging or expansion test is required and then it is unable to judge exactly the degree of stabilization for expansion. In this report, a rapid stabilization method and an expansion test method using steam for reducing slag are presented on basis of some experimental results.
At a construction work, chemical grouting for soil stabilization is generally used only for temporary purpose. However, hydrophobic polyisocyanate-type ‹aquareactive› grout named TACSS has been often applied for permanent use such as strengthening the ground under the foundation or piles of structure. Since the gel produced by an aqua-reaction is non-hydrated and has three dimensional chemical structures, it is considered that gel product formed in the soil and water can be expected to maintain the stable condition without loosing it's strength characteristics. However, experimental data about the durability of soil solidified with grout was not yet obtained, and so a follow-up test has been carried out to confirm the durability experimentally. Test specimens of soil solidified with grout were burned in the ground impregnated with an industrial chemical waste or dipped in various kinds of water such as sea water and muddy humes etc. for 19-22 years. During those years they were occasionally taken out from the ground or water and a non-destructive follow-up test was proceeded by measuring the velocity of ultrasonic wave.The durability test was completed this time and all of the specimens were submitted to the bending tests and unconfined compressive strength tests. As a result of this experiment, it is proved that the mechanical properties of soil solidified with hydrophobic polyisocyanate-type grout are superior and can maintain the mechanical characteristics without deterioration by leaching, swelling, softening etc. even under the strict circumstances for a long term of about 20 years.
The effect of the electrophilic anion coordination on the surface of four zirconium and one iron oxides with respect to the solid acid strength and the coagulation of constituent primary particles were examined. The anions Cl-, SO2-4, and PO3-4 enhanced the acid strength of these oxides by coordination, and brought about catalytic activity for esterification and isomerization of n-butane, c-hexane and 1-butene. It was found that these anions other than Cl-1 acted as a suppressor to the coagulation and joining of the primary particles, as well as a retarding agent of crystal phase transition in the coordinated oxides.
It became clear in the present study that the structure of an aggregate of ultrafine particles was strongly affected by (a) a cohesional strength among primary particles and (b) an interaction between aggregates, both of which depends on the synthesizing method of powders and a kind of raw materials used. Difference in behavior of compaction among those ultrafine powder beds during uniaxial pressing was discussed on the basis of experimental results considering a large difference in elastic strain energy accumulated in the compact beds.
The specific surface area of several kinds of zeolite, ie., Moleculite 515, Moleculite 4P-30S, Zeoharb 501, Zeoharb 502 and Itaya zeolite was estimated on the basis of the PSA (Pressure Swing Adsorption) method. PSA is accompanied by the evolution of heat and its adsorption in the zeolite bed with a corresponding recorder deflection. The results were compared with the data obtained by other adsorption methods utilizing nitrogen. This PSA method seems useful for estimation of specific surface area of zeolite as well as life estimation of zeolite adsorbent in a dynamic adsorption process.
Alumina compounds with 20-40vol% powder concentrations in two mixture systems of organic binders were prepared to discuss their flow properties and feasibility for injection molding. The selected mixture systems (A) and (B) had the bonding resin/plasticizer/lubricant content ratio of 85/10/5 and 65/20/15, respectively. The results obtained were as follows: All compounds showed a non-Newtonian flow and the type of flow could be characterized as shear thinning. Mixture system (A) flowed likely as a Bingham body, but (B) flowed as a pseudo-plastic body. The relation between apparent viscosity and powder concentration was well fit to Farris's Eq., and the inherent viscosity calculated was 8.3Pa·s for (A) and 1.1Pa·s for (B) at 165°C. Mold inner pressure patterns during injection molding differed largely in two mixture systems (A, B). In the mixture system (A) the mold inner pressure less transmitted from the injection pressure, and the filling time was slower than in the mixture system (B). Internal cracks appeared at the dewaxing stage, and their shape and size were influenced by the composition of organic binders.
To obtain concentrated silicon nitride slurries appropriate for a vibro-casting (solid casting) to fabricate large scale products such as valve cocks or refractory blocks used in glass industry, the influence of pH on deflocculation/flocculation for silicon nitride fine powder/water suspensions was investigated. The viscosity of the concentrated slurries with various pH values was measured by means of pulling up ball method under vibration. The silicon nitride fine powder-water suspensions were found to be deflocculated in the range of 2-4 and 10-12 of pH, while they were flocculated primarily between 5 and 9 of pH, and secondarily below 2 or over 13 of pH. The apparent viscosity of the concentrated and deflocculated silicon nitride slurries under vibration was lower than that of the flocculated slurries. The apparent viscosity of both deflocculated and flocculated silicon nitride slurries decreased with increasing frequency and amplitude of vibration. However, feed of vibration with high frequency and large amplitude to silicon nitride slurries raised their apparent viscosity instead.
To clarify the segregation mechanism of solid mixtures in the axial direction of a horizontal rotating conical vessel, i.e. the axial segregation mechanism, the trajectory of a particle cascading on the surface of particle bed in the vessel was calculated by a cascading model of the particles. As a result, it was estimated that a particle was transported from the wider end of the vessel to the narrower one by cascading on the warped bed surface reflecting the axial distribution of the cascading surface angle, which is associated with the distribution of the critical rotating speed ratio of the vessel in its axial direction. The axial traveling trajectories of particles cascading on the warped surface could be experimentally confirmed by using two kinds of tracer particles differing in properties in a horizontal rotating conical vessel. It was obtained that the axial segregation of particles was given by two kinds of the axial traveling behavior, given by (1) cascading behavior of particles on the warped surface from the wider end of the vessel to the narrower one and (2) rolling one along the tongue of the particle bed from the narrower end to the wider one. The final axial segregation of solid mixtures was discussed according to the axial traveling behavior (1) and (2) of the particles cascading close to the surface of particle bed with the radial segregation of the mixtures in a horizontal rotating conical vessel.
Dispersion of magnetic powder was carried out by a wet type bead mill in order to evaluate a dispersion condition of fine particles. The three-dimensional surface condition of magnetic paint film was surveyed by a Scanning Tunneling Microscope (STM). Observation of film by a Scanning Electron Microscope (SEM) and measurement of glossity were also conducted. By applying the STM, the microscopic dispersion state of fine particles was able to be evaluated because the three dimensional surface condition of magnetic paint film could be obtained quantitatively. So, the evaluation method by STM is superior to that of the glossity or by SEM. From the experimental results of STM, the operational end-point of dispersion was found to be determind by the measurement of power consumption or viscosity of the paint. The STM evaluation method should be adoptable to other fine particles.