不同养护温度下引气剂对混凝土性能的影响研究

发布时间：2018-03-14 12:38

本文选题：混凝土　切入点：含气量　出处：《硅酸盐通报》2017年06期 　论文类型：期刊论文

【摘要】：通过试验,研究了混凝土含气量的经时损失规律及其影响因素,以及养护温度和引气剂对混凝土强度、抗氯离子渗透性和微观孔结构等性能的影响。结果表明:新拌混凝土的含气量损失与混凝土的初始含气量有关,初始含气量越大,损失也会更大,且处于动态过程的新拌混凝土的含气量损失较静态过程更大;与标准养护条件相比,负温养护条件一方面会使混凝土内部的水化反应变慢,水化程度变低,另一方面水结冰也会引起体积膨胀,破坏混凝土内部的晶体结构,对混凝土内部孔结构造成了一定程度的损伤,使得混凝土抗压强度降低,电通量、气孔间距系数等参数增大;掺入引气剂会引入了大量的微小气泡,使混凝土内部小孔径的孔含量增多,在一定程度上会提高孔的连通性,从而相对减小混凝土受力面积,造成混凝土抗压强度降低,电通量增大,孔径分布也会朝着小孔径方向移动。
[Abstract]:Through experiments, the law of time-lapse loss of air content of concrete and its influencing factors, as well as the strength of curing temperature and air-entraining agent to concrete are studied. The results show that the loss of air content of fresh concrete is related to the initial gas content of concrete, and the greater the initial gas content is, the greater the loss will be. Compared with the standard curing conditions, the negative temperature curing conditions can slow down the hydration reaction and decrease the hydration degree of the concrete, and the loss of air content of the fresh concrete in the dynamic process is greater than that in the static process, on the one hand, the negative temperature curing condition will make the hydration reaction slow and the hydration degree lower in the concrete. On the other hand, water icing will also cause volume expansion, destroy the crystal structure of concrete, cause some damage to the inner pore structure of concrete, reduce the compressive strength of concrete, increase the electrical flux, the coefficient of pore spacing and so on. A large number of tiny bubbles will be introduced into the air entraining agent, which will increase the pore content of the small pore diameter in concrete, improve the connectivity of the pores to some extent, and thus reduce the force area of concrete and reduce the compressive strength of concrete. With the increase of the electric flux, the pore size distribution will also move towards the small aperture.
【作者单位】：兰州交通大学甘肃省道路桥梁与地下工程重点实验室;兰州交通大学道桥工程灾害防治技术国家地方联合工程实验室;甘肃省交通规划勘察设计院股份有限公司;
【基金】：长江学者和创新团队发展计划滚动资助(IRT_15R29) 国家自然科学基金(51268032)
【分类号】：TU528

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