活性掺合料对混凝土抗碳化性能影响的研究

研究了强度等级(C30和C45)、龄期(28 d和120 d)、矿物掺和料(矿粉和粉煤灰)质量掺量对掺有脂肪族高效减水剂(SAF)的混凝土抗碳化性能的影响,并建立了C30/C45混凝土在28 d/120 d龄期的碳化深度与矿粉/粉煤灰掺量比例之间的回归模型。结果表明:水胶比的降低、养护龄期的延长都能提高水泥石的密实度,从而提高抗压强度和抗碳化性能;混凝土抗碳化性能随矿粉掺量的上升、粉煤灰掺量的下降而提高;当矿粉掺量占胶凝材料质量的37.5%时,C30混凝土的抗碳化性能最佳;当矿粉掺量占胶凝材料质量的31.9%时,C45混凝土的抗碳化性能最佳;当龄期增加时,粉煤灰掺量比例越大则碳化深度的下降幅度越大;矿粉和粉煤灰掺量的相对比例变化时,对低强度混凝土的影响程度要大于高强度混凝土。

Influences of Active Admixtures on Anti-Carbonization Performance of Concrete

The influence of strength grade (C30 and C45), age (28 d and 120 d) and mineral admixture (mineral powder and fly ash) mass content on the anti-carbonization performance of concrete mixed with high efficiency aliphatic superplasticizer(SAF) was studied. A regression model between the carbonization depth of C30/C45 concrete at 28 d/120 d age and the proportion of mineral powder/fly ash was established. The results show that the reduction of water-binder ratio and the extension of curing age improve the compactness of cement stone, which improve the compressive strength and carbonization resistance. The anti-carbonization performance of concrete increases with the increase in the amount of mineral powder and the decrease in the amount of fly ash. When the mass fraction of mineral powder in the cementing material is 37.5%, the carbonization resistance of C30 concrete is the best. When the mass fraction of mineral powder in the cementing material is 31.9%, the carbonization resistance of C45 concrete is the best. When the age increases, the greater the proportion of fly ash, the greater the decrease in carbonization depth. When the relative proportion of mineral powder and fly ash content changes, the degree of influence on low-strength concrete is greater than that of high-strength concrete.