增强珊瑚骨料混凝土毛细吸水性能与预测模型

Capillary Water Absorption Properties and Prediction Model of Reinforced Coral Aggregate Concrete

本工作设计了三种类型的珊瑚骨料混凝土(CAC),包括粉煤灰CAC、硅灰CAC和矿渣CAC,粉煤灰CAC为对照试件。采用改进的ASTM C1585方法,研究了养护28 d和60 d后CAC的毛细吸水特性,分析了硅灰和矿渣对CAC毛细吸水性能和孔隙率的影响,并建立了初始吸水率预测模型。结果表明:硅灰和矿渣的掺入均显著减低了CAC的毛细吸水率,但随着硅灰和矿渣含量的增大,硅灰和矿渣对CAC毛细吸水率的降低作用减弱。随着养护时间的延长,硅灰和矿渣对毛细吸水率的降低作用也减弱。28 d时,含有4%硅灰或20%矿渣的CAC毛细吸水率是最低的;60 d时,含有6%硅灰或20%矿渣的CAC毛细吸水率是最低的。在整个吸水阶段,硅灰对CAC累积吸水量的降低作用大于矿渣。添加4%的硅灰或20%的矿渣能够有效降低CAC的孔隙率,同时,理论孔体积和二次吸水率之间有较好的相关性。通过回归分析建立的CAC初始吸水率预测模型能够预测不同含量硅灰和矿渣CAC的初始毛细吸水率。

Three types of coral aggregate concrete(CAC)were designed including fly ash CAC,silica fume CAC and slag CAC,fly ash CAC was used as a reference sample.The improved ASTM C1585 method was used to investigate the capillary water absorption characteristics of CAC at 28 d and 60 d.The influence of silica fume and slag on CAC capillary water absorption and porosity was analyzed,and the initial sorptivity prediction model was established.The results indicate that the incorporation of silica fume and slag significantly reduced the capillary water absorption of CAC,but the reducing effect on the capillary water absorption of CAC decreased with the increase of silica fume and slag content.With the increase of curing age,the decreasing effect of silica fume and slag on capillary water absorption is also weakened.At 28 d,the capillary water absorption of CAC containing 4%silica fume or 20%slag is the lowest;at 60 d,the capillary water absorption of CAC containing 6%silica fume or 20%slag is the lowest.In the entire water absorption stage,reduction effect of silica fume on the cumulative water absorption of CAC is greater than that of slag.Adding 4%silica fume or 20%slag can effectively reduce the porosity of CAC.At the same time,there is a good correlation between theoretical pore volume and secondary water absorption.The initial water absorption prediction model of CAC established by regression analysis can predict the initial water absorption rate of CAC with different content of silica fume and slag.