负温混凝土的力学性能及其影响因素的研究

主要研究了水灰比,矿物掺合料,外加剂及预养制度对负温混凝土抗压强度、抗折强度、轴心抗压强度和静弹性模量的影响。结果表明:负温混凝土-7+28d的各项力学性能的损失率随水灰比的增大而增加。防冻剂和引气剂可以有效地降低混凝土-7+28d的上述各项力学性能损失率,同引气剂相比防冻剂更有效;除抗压强度外,粉煤灰和矿渣对混凝土的-7+28d的各项力学性能不利;经48h预养后所有配合比混凝土的力学性能损失率均显著减小,预养时间对负温混凝土的力学性能的影响要比水灰比、引气剂、防冻剂、矿渣及粉煤灰明显;同其他三种力学性能相比,负温混凝土的轴心抗压强度损失率明显较大。

STUDY ON THE MECHANICAL PERFORMANCE AND INFLUENCING FACTORS OF THE CONCRETE AT SUBZERO TEMPERATURE

It has been studied that the effects of the ratio of water and cement,mineral additive,admixture and curing system on the compressive strength,the Young's modulus,the axial compressive strength and bending strength.The results reveal that the loss rate of the mechanical properties of the negative concrete increases with the increase in ratio of water and cement at-7 28 d and anti-freezing agent and air-entraining agent can descend it but as compared with air-entraining agent,anti-freezing agent is more effective.Except the compressive strength,fly ash and slag are disadvantageous to other mechanical properties of-7 28d concrete.After cured for 48h the loss rate of the mechanical properties of concrete with all mix proportions is decreased greatly and curing time is more prominent to improve the mechanical properties of the negative concrete than the ratio of water and cement,additive and mineral admixture.Compared with other mechanical performances the loss rate of the axial compressive strength is greater.