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提高抗裂性是混凝土工程中的一个重要课题。从优化混凝土配合比的角度,研究了配合比参数水胶比、矿物掺合料用量及品种、单位用水量和灰砂比等对箱梁用高强混凝土早期抗裂性能的影响。研究表明:提高水灰比、添加适当掺量的掺合料、适当降低胶凝材料总量有利于提高抗裂性能。当粉煤灰掺量在10%～20%时,粉煤灰掺量对早期抗裂性的影响不大,反而在掺量为10%时略优,单掺粉煤灰略优于双掺粉煤灰和矿渣微粉。各影响因素对水泥净浆的影响趋势与砂浆和混凝土相似,但影响程度不同。水胶比对抗裂性能的影响最大,其次为掺合料用量和胶凝材料总量。掺合料用量在砂浆中对抗裂性的影响略小于在水泥净浆中的影响。
To improve crack resistance is an important issue in concrete engineering. From the perspective of optimizing the mix ratio of concrete, the effects of the ratio of water to binder, the amount and variety of mineral admixtures, the unit water consumption and the ratio of sand to sand on the early crack resistance of high strength concrete for box girder were studied. The research shows that increasing the water-cement ratio, adding the appropriate amount of admixture, and properly reducing the total amount of cementitious material are favorable for improving crack resistance. When the content of fly ash is 10% ~ 20%, the content of fly ash has little effect on the early crack resistance, but slightly better when the content of fly ash is 10% Fly ash and slag powder. The impact of various factors on the impact of cement paste and mortar and concrete trends similar, but the impact of different degrees. The water-cement ratio has the greatest impact on the cracking resistance, followed by the amount of admixture and the total amount of cementitious material. The amount of admixture in the mortar crack resistance slightly less than the impact in the cement paste.