不同矿物掺合料水工混凝土抗冻性能

Frost Resistance of Hydraulic Concrete with Different Mineral Admixtures

为了研究水工混凝土的抗冻性能,本文通过不同矿物掺合料(粉煤灰、石灰石粉和矿粉)制备混凝土试件,对不同冻融循环次数下混凝土的质量变化、抗压强度和动弹性模量变化进行研究,结合CT扫描测试其内部孔隙变化,综合分析水工混凝土的抗冻性能。结果表明:最佳掺合方式为复掺石灰石粉和粉煤灰(LFC),可以有效改善混凝土的抗冻性能;经过150次冻融循环后,其抗压强度仍残存68.64%,相对动弹性模量为79.81%;经过工业CT扫描,其孔隙率与基准混凝土(NC)相似,分别为0.881%和0.865%,但是LFC的中大孔体积占比明显优于NC,孔隙结构也更优。

To study the frost resistance of hydraulic concrete,concrete samples were prepared with different mineral admixtures(fly ash,limestone powder and mineral powder).The changes in mass,compressive strength and dynamic elastic modulus of concrete under different numbers of freeze-thaw cycles were analyzed,and the changes in internal pores were acquired by CT scanning to allow a comprehensive study of the frost resistance of hydraulic concrete.The results show that the optimized blending method uses the addition of limestone powder and fly ash(LFC),effectively improving the frost resistance of concrete.After 150 freeze-thaw cycles,the compressive strength remains 68.64%,the relative dynamic elastic modulus is 79.81%,and the porosities are close to that of the reference concrete(NC)by industrial CT scanning with 0.881%and 0.865%,respectively.However,the volume proportion of medium and large pores in LFC is better than that of NC,and the pore structure was also superior.