摘要
基于粉煤灰抑制碱-硅反应(ASR)的效果,采用22种粉煤灰对具有碱活性的砂岩骨料进行ASR抑制试验,提出了用粉煤灰的化学成分因子CFA来评价粉煤灰品质、优选粉煤灰.首先用其中的12种粉煤灰进行砂浆棒快速法试验,分析了粉煤灰主要化学成分对ASR的影响,确定CFA的表达式为[m(CaO)+0.7356m(R2O)+1.4607m(MgO)-1.8299m(SO3)]/[0.7928m(SiO2)-2.1705m(Fe2O3)+0.5673m(Al2O3)];用其余10种粉煤灰进行砂浆棒快速法试验和60℃混凝土棱柱体法试验,验证了CFA的合理性,比较了CFA和另外3种粉煤灰品质评价指标与粉煤灰对ASR抑制效果的相关系数.结果表明:粉煤灰的单一化学成分不足以全面反映粉煤灰对ASR的抑制效果;CFA与粉煤灰对ASR的抑制效果有较好的相关性;当CFA≤0.400时,约30%的粉煤灰掺量可以有效抑制ASR;当CFA>0.400时,粉煤灰掺量应更大.
22 kinds of fly ashes were tested together with a kind of alkali-active sandstone aggregate and a chemical composition index C_（FA） was used to evaluate the quality of fly ash and choose proper fly ash based on the effectiveness of fly ash in suppressing alkali-silica reaction（ASR）.Firstly 12 kinds of fly ashes were tested with the accelerated mortar bar test method to investigate the effect of the main chemical composition of fly ash on ASR,and by regression the exact form of C_（FA） was obtained as C_（FA）=[m（CaO）＋0.735 6m（R_2O）＋1.460 7m（MgO）-1.829 9m（SO_3）]/[0.792 8m（SiO_2）-2.170 5m（Fe_2O_3）＋0.567 3m（Al_2O_3）].The other 10 kinds of fly ashes were tested both with the accelerated mortar bar test method and the 60 ℃ accelerated concrete prism test method to validate the rationality of C_（FA）.The correlation coefficients between four different evaluation indices of the ASR suppression effect of fly ash and various expansion test results were also compared.The results show that the chemical C_（FA） of fly ash correlates much better with its ASR suppression effect than any single chemical composition does;the fly ash with a C_（FA）≤0.400 could mitigate ASR effectively at a cement replacement level of around 30%,otherwise a higher level would be required.
出处
《建筑材料学报》
EI
CAS
CSCD
北大核心
2009年第2期239-243,252,共6页
Journal of Building Materials
基金
国家自然科学基金委员会
二滩水电开发有限责任公司雅砻江水电开发联合研究基金资助项目(50539040)
水利部公益性行业科研专项经费项目(200801057)
关键词
碱-硅反应
化学成分因子
粉煤灰
alkali-silica reaction
chemical composition index
fly ash
