The development of strength and the form of attack of cement-based material made of limestone powder at low water-binder ratio under low-temperature sulfate environment were studied. The results indicate that when wat...The development of strength and the form of attack of cement-based material made of limestone powder at low water-binder ratio under low-temperature sulfate environment were studied. The results indicate that when water-binder ratio is lower than 0.40, the cement-based material with limestone powder has insignificant change in appearance after being soaked in 10% magnesium sulfate solution at low temperature for 120 d, and has significant change in appearance after being soaked at the age of 200 d. Expansion damage and exfoliation occur on the surface of concrete test cube at different levels. When limestone powder accounts for about 28 percent of cementitious material, with the decrease of water-binder ratio, the compressive strength loss has gradually decreased after the material is soaked in the magnesium sulfate solution at low temperature at the age of 200 d. After the specimen with the water-binder ratio of less than 0.4 and the limestone powder volume of greater than 20% is soaked in 10% magnesium sulfate solution at low temperature at the age of 200 d, gypsum attack-led destruction is caused to the concrete test cube, without thaumasite sulfate attack.展开更多
固定水胶比为0.24,通过I级粉煤灰替代砂浆中30%~70%水泥的强度试验,研究了Na 2 SO 4对粉煤灰-水泥砂浆体系的激发效果。结果表明:不掺激发剂时,砂浆抗压和抗折强度随粉煤灰替代率的增加成比例下降,且粉煤灰替代率达50%以上时对强度增长...固定水胶比为0.24,通过I级粉煤灰替代砂浆中30%~70%水泥的强度试验,研究了Na 2 SO 4对粉煤灰-水泥砂浆体系的激发效果。结果表明:不掺激发剂时,砂浆抗压和抗折强度随粉煤灰替代率的增加成比例下降,且粉煤灰替代率达50%以上时对强度增长速率有显著提升作用。粉煤灰替代率不低于50%时,1%的Na 2 SO 4掺量对砂浆抗压强度增进效果最佳,与此不同的是,Na 2 SO 4掺量越高,对砂浆抗折强度的增长越有利。随龄期增长,Na 2 SO 4激发粉煤灰-水泥砂浆的折压比显著下降,但抗折强度均在5.0 MPa以上。展开更多
文摘The development of strength and the form of attack of cement-based material made of limestone powder at low water-binder ratio under low-temperature sulfate environment were studied. The results indicate that when water-binder ratio is lower than 0.40, the cement-based material with limestone powder has insignificant change in appearance after being soaked in 10% magnesium sulfate solution at low temperature for 120 d, and has significant change in appearance after being soaked at the age of 200 d. Expansion damage and exfoliation occur on the surface of concrete test cube at different levels. When limestone powder accounts for about 28 percent of cementitious material, with the decrease of water-binder ratio, the compressive strength loss has gradually decreased after the material is soaked in the magnesium sulfate solution at low temperature at the age of 200 d. After the specimen with the water-binder ratio of less than 0.4 and the limestone powder volume of greater than 20% is soaked in 10% magnesium sulfate solution at low temperature at the age of 200 d, gypsum attack-led destruction is caused to the concrete test cube, without thaumasite sulfate attack.
文摘固定水胶比为0.24,通过I级粉煤灰替代砂浆中30%~70%水泥的强度试验,研究了Na 2 SO 4对粉煤灰-水泥砂浆体系的激发效果。结果表明:不掺激发剂时,砂浆抗压和抗折强度随粉煤灰替代率的增加成比例下降,且粉煤灰替代率达50%以上时对强度增长速率有显著提升作用。粉煤灰替代率不低于50%时,1%的Na 2 SO 4掺量对砂浆抗压强度增进效果最佳,与此不同的是,Na 2 SO 4掺量越高,对砂浆抗折强度的增长越有利。随龄期增长,Na 2 SO 4激发粉煤灰-水泥砂浆的折压比显著下降,但抗折强度均在5.0 MPa以上。
