油菜秸秆纤维混凝土抗碳化性能的试验研究

Experimental study on carbonation resistance of rape straw fiber concrete

运用正交试验,制作油菜秸秆纤维混凝土试件,探究水灰比(0.45、0.50、0.55、0.60)、油菜秸秆纤维长度(15~20、>20~25、>25~30、>30~35 mm)和秸秆纤维体积掺量(0.50%、1.00%、1.50%、2.00%)对油菜秸秆纤维混凝土抗碳化性能的影响。极差分析结果表明,3因素对油菜秸秆混凝土抗碳化性能影响的大小依次为水灰比、秸秆纤维长度、秸秆纤维体积掺量,最优组合为水灰比0.45、秸秆纤维长度为>30~35 mm、秸秆纤维体积掺量1.50%。取最优水平组试件作电镜扫描观察,发现油菜秸秆纤维的掺入,能够改善水泥浆体内部孔隙结构,使混凝土碳化深度最多可减小35.31%,从而提高混凝土的抗碳化性能。采用最小二乘法回归分析建立的油菜秸秆纤维混凝土碳化深度预测模型,验证离散系数接近0.05。

Under the condition of orthogonal test,rapeseed straw fiber concrete specimen were made to study the influence of water-cement ratio(0.45,0.50,0.55,0.60),straw fiber length(15~20 mm,>20~25 mm,>25~30 mm,>30~35 mm)and straw fiber volume content(0.50%,1.00%,1.50%,2.00%)on the carbonation depth of rape straw fiber concrete.The orthogonal test result shows that the influence of the three variables on the carbonization resistance of rape straw fiber concrete is water-cement ratio,straw fiber length and straw fiber volume content.The optimal level for carbonization resistance of rape straw fiber concrete is the water-cement ratio of 0.45,the straw fiber length of 30-35 mm,and the straw fiber volume content of 1.50%.The electron microscope scanning observation was found that the addition of straw into ordinary concrete could improve the microporous structure of cement slurry,so that the carbonation depth of concrete can be reduced by up to 35.31%,which indicates its carbonization resistance improves.The carbonation depth prediction model of rape straw fiber concrete was built through regression analysis of the least square method,and it was verified that the dispersion coefficient is close to 0.05.