拉压应力下自密实混凝土碳化性能试验研究  

Experimental Study on Carbonation of Self-compacting Concrete under Tensile and Compressive Stresses

作　　者：郑建岚[1] 黄利频[1] 

机构地区：[1]福州大学土木工程学院,福建福州350108

出　　处：《建筑材料学报》2013年第1期115-120,共6页Journal of Building Materials

基　　金：国家自然科学基金资助项目(50878056);福建省科技厅重点项目(2009H0027)

摘　　要：制作了4组单掺粉煤灰自密实混凝土试件和2组复掺粉煤灰与矿渣的自密实混凝土试件,以及1组用以对比的普通混凝土试件.通过快速碳化试验研究各种拉、压应力水平,掺和料用量等因素对自密实混凝土抗碳化性能的影响规律.研究表明:在各种拉、压应力水平下,掺量在40%(质量分数,下同)以内时粉煤灰对混凝土碳化性能的影响很小,超过40%后其影响迅速增大,而复掺粉煤灰与矿渣后混凝土的抗碳化性能大大改善,两者按质量比1∶1复掺时,水泥取代率可提高至60%.自密实混凝土的碳化深度随着拉应力水平的增大而增大,而随着压应力水平的增大呈现先减小后增大的变化趋势.提出了应力状态下自密实混凝土碳化深度预测模型的建立方法.Four series of self-compacting concrete（SCC） specimens containing fly ash, two series of SCC specimens containing both fly ash and ground granulated blast slag, and one series of ordinary concrete specimens without mineral admixture added were prepared. Using the accelerated carbonation test method, the influences of tensile stress rates, compressive stress rates, and use level of mineral admixture on the carbonation resistance of SCC were studied. The results indicate that, under all stress rates, fly ash has little effect on carbonation of SCC when its replacement percentage is less than 40% （by mass）, but the carbonation depth increases quickly when the replacement percentage is more than 40~. The use of both fly ash and slag greatly improve the carbonation resistance of SCC. If fly ash and slag admixture ratio is 1 ＂ 1, the replacement percentage can be increased to 60%. The carbonation depth of SCC increases as ten- sile stress rate rises, whereas it decreases firstly and then increases as compressive stress rate rises. The relationship between carbonation rate and stress rate was also established. The results can provide a meth- od for establishing the model for predicting the carbonation depth of SCC.

关 键 词：自密实混凝土 矿物掺和料 应力水平 碳化深度 碳化速率 

分 类 号：TU528.01[建筑科学—建筑技术科学]