水利学报2019，Vol.50Issue(4)：506-515,10.DOI:10.13243/j.cnki.slxb.20181060
低温养护下溴化锂对水泥早期水化的影响
Effect of lithium bromide on early hydration process of cement at low temperature
摘要
Abstract
The traditional early strength components can not meet the requirements of green and high performance concrete, and the researches of early strength accelerators at low temperature (especially 5℃) were relatively few, and their effects were limited, and the mechanism was also not understood well. In this study, as an early strength component, the effect of LiBr on the compressive strengths and setting times at5°C were investigated, and its effect on the early hydration process of cement was also discussed. The results show that with the addition of LiBr at low temperature of 5℃, both the initial setting and final setting time of cement paste are slightly shortened, which can significantly accelerate the development of the early strength of the mortar speciment, and thestrength is still greatly improved at 28 d. Meanwhile, the compressive strengths of motars mixed with 0.5％ LiBr can increased by 383％, 54％, 41％ and 11％ at1 d, 3 d, 7 d and 28 d respectively, each of them is close to the strengths of the contrast sample cured at20℃ at the same age. The presence of LiBr can promote the dissolution of C3 S at low temperature, resulting in a significant increase in its dissolved amount. With the increased amount of Ca (OH) 2 dissolved and the solution pH value, it is beneficial to the precipitation reaction of hydration products. At low temperature, LiBr can promote hydration reaction of cement at the early stage, and shorten the induction period of cement hydration, advance the acceleration period, and increase the maximum heat release rate and the heat release rate. The presence of LiBr can make the cement hydration entered into the D stage earlier which is controlled by the diffusion factor. A large amount of Ca (OH) 2 is formed in the products after only12 hours of hydration, and some calcium silicate hydrate and hydrated calcium bromoaluminate products are also produced.关键词
低温/早强剂/溴化锂/溶解/水化Key words
low temperature/early strength accelerator/lithium bromide/solution/hydration分类
化学化工引用本文复制引用
张丰,白银,蔡跃波,陈波,宁逢伟..低温养护下溴化锂对水泥早期水化的影响[J].水利学报,2019,50(4):506-515,10.基金项目
国家重点研发计划项目(2016YFC0401609) （2016YFC0401609）
国家自然科学基金项目(51739008) （51739008）
中央级公益性科研院所基本科研业务费专项(Y419004) （Y419004）
云南省交通运输厅行业科技攻关项目(云交科教[2016]56号) （云交科教[2016]56号）
