橡胶浮石混凝土的抗冻性能及微观结构

为探究冻融循环条件下橡胶浮石混凝土宏观性能和孔隙结构的变化规律,进行冻融循环、单轴压缩试验,通过扫描电子显微镜(SEM)以及核磁共振(NMR)技术对橡胶浮石混凝土抗冻性进行分析,同时建立其抗冻性预测模型.结果表明:加入0.12~0.18 mm的橡胶可有效降低冻融条件下浮石混凝土表面的剥蚀、内部的损伤以及力学性能的衰减,冻融200次时,加入0.15 mm橡胶的浮石混凝土质量损失率最小,为-0.14%,相对动弹性模量最大,为67.36%;冻融循环作用下橡胶浮石混凝土内部孔隙会发生劣化,小孔隙逐渐向大孔隙演变,无害孔和少害孔向有害孔和多害孔演变,加入0.12~0.18 mm的橡胶可有效抑制孔隙的劣化,使混凝土内部结构更为密实;通过橡胶浮石混凝土抗冻性预测模型可得到,加入0.15 mm橡胶的浮石混凝土抗冻周期最长,较普通浮石混凝土抗冻周期延长12.76%.

Frost resistance and microstructure of rubber pumice concrete

In order to explore the change law of macro performance properties and pore structure of rubber pumice concrete under freeze-thaw cycles, the freeze-thaw cycles and uniaxial compression test were carried out. The frost resistance of rubber pumice concrete was analyzed by scanning electron microscope(SEM)and nuclear magnetic resonance(NMR)technology, and the prediction model of frost resistance of rubber pumice concrete was established. The results show that the addition of 0.12-0.18 mm rubber can effectively reduce the surface erosion, internal damage and the attenuation of mechanical properties of pumice concrete under freeze-thaw conditions. when the freeze-thaw time is 200 the mass loss rate of pumice concrete with 0.15mm rubber is the smallest, up to -0.14%, and the re-lative dynamic modulus of elasticity is the largest, up to 67.36%. Under the freeze-thaw cycles, the internal pores of rubber pumice concrete will deteriorate, the small pores gradually evolve to the large pores, and the harmless pores and less harmful pores evolve to the harmful pores and more harmful pores. The addition of 0.12-0.18 mm rubber particles can effectively inhibit the deterioration of pores and make the internal structure of concrete more compact. According to the prediction model of frost resistance of rubber pumice concrete, the frost resistance period of pumice concrete with 0.15 mm rubber is the longest, which is 12.76% longer than that of ordinary pumice concrete.