预湿陶砂对混凝土板早期湿度分布及发展的影响

摘要

Influences of presoaked light-weight aggregate(PSLWA) volume fraction and water-binder ratio on early-age interior relative humidity(IRH) distribution and development of high-,moderate-and low-strength concrete slabs with casting surface exposed to indoor environment were investigated.Results show that with the increase volume fraction of PSLWA,the early-age globle IRH of concrete slabs are gradually increased,the duration of humidity-saturated stage is noticeably prolonged,the IRH reduction process is delayed and mitigated,the IRH non-linear gradients along the slab thickness are reduced,and the ratio of IRH-saturated zone is increased.As the internal curing water reaches about 60 kg/m3,the globle IRH of high-and moderatestrength concrete slabs stays above 92 ％ within 28 days.The lower the matrix water-binder ratio,the stronger the positive internal curing effect of PSLWA,and the thinner the zone affected by surface-drying.However,internal curing by PSLWA could not eliminate the surface-drying effect of high-,moderate-and low-strength concrete slabs under indoor dry environment.%研究了室内单面干燥条件下预湿陶砂轻骨料(PSLWA)掺量(体积分数)及水胶比(质量比)对高、中、低强混凝土板28 d内部相对湿度(IRH)分布及发展的影响.结果表明:随PSLWA掺量增大,高、中、低强混凝土板湿度饱和期延长,板湿度水平整体提高,湿度下降延缓,板厚方向上湿度梯度减小,湿度饱和区面积比例增大;引入内养护水约60 kg/m3,高、中强混凝土板28 d内部相对湿度可维持在92％以上;随基体水胶比降低,PSLWA内养护作用增强,表面干燥影响深度减小;PSLWA不能彻底消除室内单面干燥条件下高、中、低强混凝土板中的表面干燥效应.