Recently, alkali aggregate reaction, one type of concrete deterioration, has been found frequently throughout the world.
In this work, in order to elucidate the reaction mechanism, scanning electron microscopic observation and electron probe microanalysis were carried out on reaction products on the fracture surfaces of aggregate in concrete. The results clarified that these reaction products are classified into the following three types, i.e.,
(1) Na₂O-K₂O-SiO₂ system,
(2) Na₂O-K₂O-Ca0-SiO₂ system, and
(3)(Na₂O)-K₂O-CaO-SiO₂ system,
based on the chemical compositions. Products of (1) and (2) types are jelly-like materials probably caused by, the alkali-silica reaction, but that of (3) type is rosette-like one probably caused by taking K off layered silicate. From these facts, it is indicated that the latter material is one of the alkali-silicate reaction products, and that this material is characterized by the presence of mica or mica clay mineral in aggregate.
Furthermore, mineralogical compositions of above aggregates were investigated by means of X-ray diffraction technique, giving the results that they had still a little amount of reactive minerals.

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The effect of base and humus (organic matter) on the viscosity and plasticity of Kibushi-clay (sedimentary kaolinitic clay with organic matter occurred in Seto, Japan) has been studied. The following four chemical treatments were applied to the elutriated Kibushi-clay. 1) water leaching, 2) 0.05 N hydrochloric acid treatment to reduce the adsorbed basic elements, 3) 3% hydrogen peroxide treatment to decompose the humus, 4) subsequent application of 2) and 3) treatments to remove both bases and humus. These treated clays were examined mineralogically and chemically. The viscosity and plasticity of these treated clays were compared in relation to their chemical properties. The viscosity of the slip increased in the order. H₂O treat.<HCl treat.<H₂O₂ treat.<HCl+H₂O₂ treat.
On the other hand, the plasticity of clay indicated by the amount of bound water on the surface of clay particle increased in the reverse order described above. Therefore, it is concluded that the viscosity and plasticity of clays are affected by the presence of humus and base in the order.
humus+base>humus>base.

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Montmorillonite-α-naphthylamine complex (MNC) and saponite-α-naphthylamine complex (SNC) were carbonized below 1673 K under nitrogen. Polymerization of α-naphthylamine in the clay began such high temperature as 773 K and proceeded with raising of temperature. Not more than 10 wt % of the carbon remained in the complex after heating to about 1073 K, which suggests that about ¹/₄ of the clay surface was covered with the resultant carbon layer. Such carbon layer acted to enhance thermal stability of the layered structure than that of the raw clay by 200 K. After carbonization, MNC resulted in a fine and homogeneous porous structure in contrast to a dense structure from SNC. Possible applications of these characteristic structures are discussed.

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Fluoro tetrasilicic mica (TSM), Na [Mg_2.5 Si₄O₁₀F₂] is an unique cation exchanger among-a variety of silicate minerals, because it has no acid sites on the silicate sheet. The studies on the methanol conversion with a metal ion-exchanged TSM (Me-TSM) have revealed that the silicate sheet of TSM is catalytically inactive and the catalytic activities of Me-TSM's are individually different by the exchanged metal ion. The facts suggest that TSM is a suitable support for studying the catalytic activity of metal ion in a heterogeneous catalysis.
Cu (II)-TSM catalyzed the dehydrogenation of methanol to form methyl formate, 2CH₃OH→HCOOCH₃+2H₂ (1), selectively and the catalytic activity did not change at all by the long use for the catalysis. ESR studies showed that Cu (II) ions in Cu (II)-TSM retained the divalent state throughout the reaction, although they were exposed to methanol vapor at 240°C. The facts indicate that Cu (II) ion is the active species for the methanol dehydrogenation, (1). The high reduction resistivity is understandable, considering that the interlayer Cu (II) ion is a constituent of the layer structure to counterbalance the negative charge of silicate sheet.
The catalytic activity of Cu (II)-TSM is superior to that of the patent catalysts claimed for the synthesis of methyl formate. When the reactions were conducted with Cu (II)-TSM at 300°C and 400°C alternately, the higher activity was observed at the lower temperature. The facts suggest that the dehydrogenation of methanol is not facilitated only by the exposed Cu (II) ions but also by the Cu (II) ions located in the interlayer region of TSM especially at the temperatures below 300°C.
The dehydrogenation (1) was markedly retarded when ammonia occupied two or more of six coordination sites of Cu (II) ion. Since the two silicate sheets occupy the other two coordination sites, it is inferred that the selective dehydrogenation to methyl formate is catalyzed by the Cu (II) ion which has at least three vacant sites available for coordination of methanol. The inference is consistent with the reaction mechanism revealed by tracer studies with deutrated methanol. The reaction mechanism illustrated in the text (Scheme 2) shows that methanol requires three vacant sites to transform into the key intermediate of the reaction.
Besides this particular synthetic mica, TSM, we have a variety of clay minerals. Extensive investigations on the catalysis of clay derivatives are expected to afford a lot of useful informations to design a new catalyst with clay intercalates.

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The adsorption and reactions of aromatic molecules in the interlayer of transition metal ion (Cu²⁺, Fe³⁺, Ru³⁺)-exchanged montmorillonites have been investigated by resonance Roman spectroscopy, supplemented by visible, ESR and infrared spectroscopy. Aromatic molecules are oxidized by transition metal ions in the interlayer to their cations which are stable enough at room temperature. Monosubstituted benzenes which have low ionization potentials further dimerize to form cation radicals of the 4, 4'-disubstituted biphenyl type, whereas benzene and biphenyl polymerize to form poly-pphenylene cation. Thiophene and 3-methylthiophene also polymerize to form poly-thiophene cations. Adsorbed species of anilines on transition metal ion-exchanged montmorillonites are complicated by the formation of various kinds of polymers, while the formation of benzidine cation is observed in adsorption from dilute aqueous solution or from vapor phase.

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Local structures around Cu²⁺ ions in Cu-montmorillonite and in intercalated compound of Cu-montmorillonite and e-caprolactam were studied by X-ray absorption spectroscopy; EXAFS and XANES, using laboratory-scale equipment. Cu²⁺ions in Cu-montmorillonite coordinate about 6 water molecules and the Cu-0 (in water) distance was 0.19 nm. The water molecules were removed by vacuum drying at 150°C, and the Cu²⁺ions contacted with oxygen atoms in tetrahedral sheet of montmorillonite and the Cu-0 or Cu-Si distances were 0.19 and 0.25 nm.The model for adsorption site of Cu²⁺ ions were proposed. The local structure around the Ce ions was changed by heating the samples at 260°C for 5 hours. After the 260°Ctreatment, Cu²⁺ions existed in tetrahedrons of oxygen atoms where Cu-0 distance was 0.2 nm, which was similar to the local structure in CuO.
The interlayer distance of Cu-montmorillonite was 1.22 nm. Although the interlayer distance was increased to 1.53 nm by forming the intercalated compound withe-caprolactam, local structure around Cu²⁺ions was not changed. The model that two layers of water molecules and one layer of ε-caprolactam molecules existed between the silicate layers was proposed. The ε-caprolactam was polymerized by heating at 260°Cfor 10 hours, accompanied by the great increase in theinterlayer distance from 1.53 to 12.1 nm. Following this, Cu²⁺ions were reduced to metallic copper whose particle size was estimated to be about 10 nm by X-ray diffraction peak broadness. The metallic copper was oxidized by aging at 25°C for 3 weeks in atmospheric environment, accompanied by decrease in interlayer distance to 5.7 nm. Local structure around the Cu²⁺ions in this oxidized state was not similar to that in CuO but to that in Cu-montmorillonite.

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The use of the MAS techniques enables ²⁹Si-NMR to be obtained with the resolution of resonances from silicon atoms in chemically different microenvironments, namely different degrees of Si (nAl) coordinations in frameworks or layered structures and Si-O-Si bonding angles in silicate networks. On the other hand the use of the ²⁷Al-MASNMR techniques can result in the resolution of distinction of the Al (-O) coordination states.
In this paper, the following items are discussed:(1) The relation between ²⁹Si-chemical shifts and Si-Al micro-ordering (Si (nAl) configurations) for zeolites.(2) Si/A1 ratios of zeolitic frameworks.(3) Information of the Al (-0) coordination states obtained from ²⁷Al-MASNMR and Loewenstein's rule for aluminosilicate networks.(4) The applications of MASNMR to various natural zeolites; the comparison of the Si/A1 ratios of the framework structure with the bulk. The problems of identification “clinoptilolite” and “heulandite”(5) The ²⁹Si-and ²⁷Al-MASNMR investigations for various phyllosilicates: kaolinites (1: 1 dioctahedral), antigorite and chrysotile (1: 1 trioctahedral), pyrophyllite, montmorillonite and sericite (2: 1 dioctahedral), and talc, vermiculite and chlorite (2: 1 trioctahedral).(6) The unique ²⁹Si-and ²⁷Al-MASNMR results of sepiolite and attapulgite (palygorskite) with unusual phyllosilicate structures.(7) Detection of the microstructures by MASNMR for allophane, amorphous clay minerals.

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