Yao Wang, Guo Baolin, Yang Zhenyu, Yang Xingxing, Guo Yongzhi, Zhao Fangli, Wang Baomin
Shandong Hi-Speed Company Limited, Jinan 250014, China.
Shandong Province Bridge and Tunnel Engineering Maintenance Technology and New Material Industry Research and Development Center, Jinan 250100, China.
Materials (Basel). 2021 Nov 22;14(22):7098. doi: 10.3390/ma14227098.
The performance of cover concrete is acknowledged as a major factor governing the degradation of concrete structures. Curing plays a vital role in the development of concrete durability. The effects of different water-binder ratios and mineral admixtures on the curing water demand of concrete were studied by the surface water absorption test. Combined with the characteristics of the hydration heat and chemically bound water of the composition cementing material system, the law of variation for curing water demand was analyzed. The results show that the addition of mineral admixtures can reduce the early hydration rate and hydration exothermic characteristics, and the hydration degree decreases with the increase of mineral admixtures. Due to the filling effect and active effect, the addition of fly ash (FA) and ground granulated blast slag (GGBS) reduces the curing water demand. The curing water demand of cover concrete decreases with the increase of mineral admixture content, and the curing water demand of pure water is the maximum and that of mix FA and GGBS is the minimum. Moreover, there is a strong correlation between the cumulative curing water demand and the chemically bound water content, indicating that the power of water migration mainly comes from the hydration activity of the cementing material system. The results provide a theoretical basis for the fine control of a concrete curing system.
混凝土保护层的性能被认为是影响混凝土结构耐久性退化的主要因素。养护对混凝土耐久性的发展起着至关重要的作用。通过表面吸水率试验研究了不同水胶比和矿物掺合料对混凝土养护需水量的影响。结合组成胶凝材料体系的水化热和化学结合水特性，分析了养护需水量的变化规律。结果表明，矿物掺合料的加入可降低早期水化速率和水化放热特性，水化程度随矿物掺合料用量的增加而降低。由于填充效应和活性效应，粉煤灰（FA）和磨细粒化高炉矿渣（GGBS）的加入降低了养护需水量。混凝土保护层的养护需水量随矿物掺合料含量的增加而降低，纯水的养护需水量最大，FA与GGBS混合时的养护需水量最小。此外，累计养护需水量与化学结合水含量之间存在较强的相关性，表明水分迁移的动力主要来自胶凝材料体系的水化活性。研究结果为混凝土养护系统的精细化控制提供了理论依据。
