The Study Of Cement Component Minerals To Adsorbtion Mechanism Of Superplastizers

In this thesis, four sorts of Portland cement component minerals (C3S,β-C2S,C3A and C4AF) have been synthesized and their adsorption to four sorts of superplastizers has been studied. The superplastizers include β-naphthalene sulfomates UNF-5, amino sulphonate formaldehyde condensate AS, acyclic sulfonates FAS and poly carboxilate ester viscrete PC. The adsorption principle of cement component minerals to different superplastizers has been discussed by means of infrared spectrum, measurement of molecular weight, surface tension of the superplastizers and ξ-potential with or without superplastizers. The results show: It is different for ξ-potential of each cement component mineral after hydration. The ξ-potential of silicate cement component minerals(C3S andβ-C2S) are negative while the ξ-potential of aluminate cement component minerals (C3A and C4AF) are positive. When cement component minerals absorb the four different sorts of superplastizers minerals themselves play an important role in the system of "mineral-water-superplastizers"for silicate cement component minerals(C3S andβ-C2S). However, for aluminate cement component minerals (C3A and C4AF) the adsorption mainly depends on their hydrated productions. For C3S andβ-C2S, the quantity of adsorption is related with particle fineness and it increases with increasing of particle surface area in generally. However, the quantity of adsorption of C3A and C4AF does not depend on particle fineness obviously. On the other hand, the quantity of adsorption is mainly related to character of the cement component minerals themselves and the superplastizers. When four sorts of cement component minerals adsorb the same sort of superplastizer the quantity of adsorption reflects the phenomenon: C3A>C4AF>C3S>β-C2S. When the same sort of cement component mineral adsorbs different sorts of superplastizers the quantity of adsorption is different. The adsorption quantity of FAS and UNF-5 is the most while the adsorption quantity of PC is the least and adsorption quantity of AS is in the middle. The particle dispersion due to train or multi-layer adsorption of the...