氯盐对碱激发矿渣净浆强度影响试验

通过对掺加氯化钠(Na Cl)、氯化钙(Ca Cl2)的碱激发矿渣(KC)净浆的无侧限抗压强度试验,研究两种氯盐对KC净浆强度的影响规律,利用X射线衍射(XRD)、热重分析(TG-DTG)、液相离子测定、水化程度测定等测试手段,分析两种氯盐对KC净浆强度的作用机理.结果表明,随着Na Cl掺量增加,KC净浆抗压强度提高;随着Ca Cl2掺量增加,KC净浆抗压强度基本不变.掺加Na Cl与Ca Cl2的KC净浆中均生成含氯水化物水化氯铝酸钙(Fs,Friedel’s salt),但Fs的生成对KC净浆强度无影响作用.掺加Na Cl的KC净浆中氢氧化钠(Na OH)的生成是导致其强度增强的主要原因,混合物中Na OH的存在提高了KC净浆的液相碱度,促进矿渣水化的进一步发生,进而生成更多的水化硅酸钙(CSH)使KC净浆强度得到提高.

Experiment of chloride effect on strength of alkali-activated slag paste

Based on the results of unconfined compression tests of alkali-activated slag (KC) paste mixed with sodium chloride (NaCl) and calcium chloride (CaCl₂), the influence law of the KC paste strength changing with chloride was studied. X-ray diffraction (XRD), thermal gravity-differential thermal gravity analysis (TG-DTG), the test of ionic concentrations in the pore solution and the test of degree of hydration were used to analyze the mechanism of effect of two kinds of chlorideon KC paste strength. The research results show that the KC paste compressive strength increased with the increase in the concentration of NaCl; and KC paste compressive strength basically unchanged with the increase in the concentration of CaCl₂. The Friedel's salt (Fs) was generated in KC paste mixed with NaCl and CaCl₂, but it has no effect on the paste strength. The generation of sodium hydroxide (NaOH) in the KC paste mixed with NaCl was the main reason for its strength enhancement. NaOH existed in the KC paste improved the liquid alkalinity of paste, promoted hydration of slag and generated more calcium silicate hydrate (CSH) to improve the paste strength.