利用快速砂浆棒法(AMBT)来评价Li2CO3和硝酸盐AN-1抑制碱硅酸反应(ASR)的能力,并且通过长期碱液高温浸泡试验方法(3a浸泡期)来确定上述2种化学外加剂对ASR抑制能力的真实性,同时对比了相同掺量的单掺矿物掺和料(SCM)砂浆棒对ASR的抑制效果.结果表明:在短期试验中,AN-1+SCM组合、Li2CO3+SCM组合和单掺SCM这3组抑制材料均能有效抑制ASR且满足AMBT规范的评定标准,其中,AN-1+SCM组合的短期抑制能力与单掺SCM时基本相同,但优于Li2CO3+SCM组合;在长期试验中,AN-1+SCM组合与Li2CO3+SCM组合的长期抑制效果显著,且优于单掺SCM时,其中,Li2CO3+SCM组合的M2砂浆棒(胶材为P· O42.5水泥,SCM为10％粉煤灰+20％磨细矿渣)对ASR的抑制效果最佳;在AN-1+ SCM组合中,AN-1的掺量阈值建议取水泥质量的0.75％～1.25％.%Supplementary cementitious materials(SCM) or chemical admixtures(CA) blended in binder can mitigate the expansions due to alkali-silica reaction(ASR) effectually.The factual effects of Li2CO3 or nitrate AN-1 against ASR were detected by means of long-term alkali immersion at high temperature,and the inhibiting capacities of Li2CO3 or AN-1 were evaluated by accelerated mortar-bars test(AMBT).AN-1 is nitrate,a new CA at a low price.In addition,the expansions of mortar bars blended with SCM only during the long-term test were compared with those of Li2CO3 or AN-1.The results obtained are shown that,the three groups of mortar bars,including AN-1+SCM group,Li2CO3+SCM group and solo SCM group,exhibit good inhibition effect during AMBT which meets the discriminant criteria on qualified ASR inhibition of AMBT.Among the short-term expansions of these three groups of mortar bars,the expansions of AN-1+SCM group as are same low as those of only SCM group,which are lower than the Li2CO3 +SCM group's.However,during the long-term test,the AN-1+SCM group and Li2CO3 +SCM group exhibit outstanding inhibition which is still maintained at low expansions,while the single SCM group does not.Among the long-term expansions of these three groups,the expansions of M2 mortar bars blended with Li2 CO3 +SCM are the lowest.Finally,the optimum AN-1 content in AN-1+SCM group is obtained and the threshold range of AN-1 content is recommended to take 0.75 ％-1.25 ％ by the mass of cement.
展开▼
