The Preliminary Study On Surface Chemical Properties Of Surfactant On Alkali-activated Slag Cement

Alkali-activated slag cement is a type of binding material using basic compound of alkali metal to activate slag(aluminosilicate), and Alkali-activated slag concrete based on which has many excellent performance, such as high strength, rapid hardening, low heat of hydration, good durability and so on. Many research achievement have been acquired mainly on the studies of activator, durability and setting time of alkali-activated slag cement and concrete. The researches and applications have be based on bad workability alkali-activated slag concrete until now. It is a mostly problem to embarrass application of alkali-activated slag cement and concrete that is big viscosity and bad workability of the new mixture with conventionality water-cement ratio. Adulterating surfactant is an important techno-means to solve the problem. Up to now, no systematic study has been done on effect mechanism of surfactant on alkali-activated slag cement and concrete. The study is an important theory foundation of researching plasticizers on alkali-activated slag cement and concrete, and has far-reaching significance to accelerate application of alkali-activated slag cement and concrete.By surface tension test, adsorbed amount test,ζpotential test and fluidity test for cement paste, the paper discusses the effect of variety surfactant and activator on surface tension, adsorbed amount,ζpotential and fluidity. Based on these, the effect mechanism of surfactant on alkali-activated slag cement and concrete has been studied. The research results can be concluded as following: (1) NaOH , Na2CO3 and Na2O·nSiO2 all debase the surface tension of water. Of which, water-glass has the best efficacity. When the modulus of water-glass is 1.5 and dosage of water-glass by Na2O is 8%, the surface tension is 39.9mN/m and reduces 33 mN/m. Naphthalene plasticizer, sulphamate plasticizer and polycarboxylate plasticizer reduce the surface tension of water less, [CH3(CH2)11N(CH3)3]Cl,[CH3(CH2)9]2N(CH3)2Cl and CH3(CH2)11(C2H4O)nH can reduce the surface tension of water better. Of which, [CH3(CH2)9]2N(CH3)2Cl has the best efficacity. When the concentration of [CH3(CH2)9]2N(CH3)2Cl is 50g/L, the surface tension is 32.5 mN/m and reduces 35.3 mN/m.(2) The effect of surfactant and alkali together on the the surface tension of water is complex. The cationic surfactants can debase the surface tension of NaOH solution.