掺合料对引气混凝土抗冻性能的影响

Influence of Admixtures on Freezing Resistance of the Air-Entraining Concrete

对掺合料的引气混凝土性能进行了研究。结果表明：在水胶比相同的情况下，无论是掺粉煤灰还是矿渣粉，混凝土抗压强度都呈随着掺量的增加而降低的趋势。单掺粉煤灰或矿渣粉的混凝土相对动弹性模量随粉煤灰或矿渣粉掺量的增加呈降低的趋势，质量损失呈增大趋势。当粉煤灰和矿渣粉复掺，总掺量为40％且比例为1：1时，试样300次冻融循环质量损失最小，但相对动弹性模量而言，与单掺矿渣粉的混凝土的质量损失接近。硬化混凝土试件的空气含量在7．78％～10．65％之间，气泡间距范围在0．202～0．382mm之间，混凝土表现出了较好的抗冻性。

Freezing resistance of the air-entraining concrete with admixtures is investigated.Results show that with the same water-cement ratio, compressive strength of the concrete reduces with the increase of mixing quantity of the fly ash or slag powder.If mixing with fly ash or slag power only, the relative dynamic elastic modulus of the concrete will de-crease with the increase of the mixing quantity of those admixtures, while the mass loss will increase.If mixing with fly ash and slag powder together, the mass loss of the concrete samples after 300 times of freezing-thawing cycles is of the minimum when the total content of those admixtures is 40% and the ratio of 1∶1.While the relative dynamic elastic modulus is close to the samples mixing with slag powder only.A relatively higher freezing resistance is obtained when the air content of the hardened concrete samples is between 7.78%~10.65%, and the range of bubble spacing is between 0.202~0.382 mm.