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针对大掺量粉煤灰混凝土早期抗渗性、抗碳化性、抗冻性相对不足等问题,通过在大掺量粉煤灰混凝土中掺入引气剂,可以显著改善这些性能。通过试验研究,结果表明:对于中低等级大掺量粉煤灰混凝土,引气后28 d的氯离子扩散系数显著减小,可以达到很低的标准。掺加引气剂后,混凝土含气量在5%以下时,大掺量粉煤灰混凝土的28 d碳化深度显著减小,都在10 mm以下。引气后,大掺量粉煤灰混凝土冻融后相对动弹性模量提高20%—40%。在一定范围内,大掺量粉煤灰混凝土的抗渗性、抗碳化性、抗冻性随着含气量的提高而增大。
Aiming at the problems of early impermeability, carbonization resistance and frost resistance of high volume fly ash concrete, these properties can be improved remarkably by incorporating air entraining agent into high volume fly ash concrete. The experimental results show that the chloride ion diffusion coefficient of 28 days after air bleed has been significantly reduced for low to mid-high fly ash concrete, which can reach a very low standard. When the air entraining agent is added, the carbonization depth of 28 days of high content fly ash concrete significantly decreases below 10 mm when the air content of concrete is below 5%. After air entrainment, the relative dynamic elastic modulus of high volume fly ash concrete increases 20% -40% after it is frozen and thawed. Within a certain range, the impermeability, carbonization resistance and frost resistance of high volume fly ash concrete increase with the increase of gas content.