【摘要】 研究了搅拌站废水对无硅灰A型掺合料(粉煤灰+矿粉)和有硅灰B型掺合料(粉煤灰+硅灰)配制的C80高强混凝土的早期和后期抗压强度的影响,结合废水、自来水及两种掺合料拌制的7 d龄期硬化水泥净浆体的XRD分析,探讨了废水对不同掺合料配制的C80高强混凝土早期强度的影响机理。结果表明:对于无硅灰A型掺合料配制的C80高强混凝土,由于废水的缓凝作用,故掺入废水会降低混凝土的早期强度;对于有硅灰的B型掺合料配制的混凝土,由于硅灰早期火山灰活性高,而搅拌站废水中Ca(OH)2含量高,有助于硅灰早期的二次水化反应进行,故掺入废水会提高混凝土的早期强度;使用废水对C80高强混凝土后期强度影响不大,且由于废水中Ca(OH)2含量较高,有助于掺合料后期二次水化反应进行,故废水配制的C80混凝土的后期强度还略高于自来水的。更多还原

【Abstract】 The influences of the wastewater in concrete plant on the compressive strength of C80 concrete made of A-type mineral admixture without silicon fume and B-type mineral admixture with silicon fume were investigated.Based XRD analyses of 7 d hardened cement pastes made of wastewater,tap water and two types of mineral admixture,the influencing mechanism was discussed.The results show that for C80 concrete made of A-type mineral admixture,the wastewater added can decrease the early strength due to the retardering action of wastewater;for C80 concrete made of B-type mineral admixture,the wastewater can increase the early strength due to the stronger secondary hydration of silicon fume resulting from the high early pozzolana reactivity of silicon fume and high content of Ca(OH)2 in wastewater;the wastewater added slightly affects the old strength of concrete,and because the high content of Ca(OH)2 in wastewater is helpful to improve the secondary hydration of mineral admixtures,the old strength of concrete mixed by wastewater is slightly more than that of concrete mixed by tap water.更多还原