大掺量矿物掺合料在蒸养混凝土中的应用研究

发布时间：2018-01-25 17:18

  本文关键词： 蒸养制度 粉煤灰 矿渣 蒸养混凝土 性能　出处：《清华大学》2015年硕士论文　论文类型：学位论文

【摘要】：蒸汽高温养护是生产预制混凝土构件的主要技术手段之一。粉煤灰和矿渣的早期水化活性低,在蒸养混凝土中的利用率非常低。本文研究了大掺量粉煤灰和矿渣对蒸养混凝土的性能的影响,主要结论如下:(1)静停时间的长短(1 h、3 h、6 h)对胶凝材料后期的水化程度、混凝土后期的抗压强度和氯离子渗透性的影响均较小。静停时间为3 h时,基本能够使混凝土获得足够抵抗蒸汽和温升对结构造成损伤的能力。(2)延长恒温时间与提高恒温温度对复合胶凝体系的水化的促进作用大于纯水泥;恒温蒸养温度达到70℃时,进一步提高温度对水泥的水化程度有负面的作用;对于含大掺量粉煤灰或矿渣的胶凝材料,恒温蒸养温度达到80℃时,进一步提高温度对水化程度有负面作用。(3)为获得理想的拆模强度,粉煤灰的掺量不宜超过40%,最佳蒸养温度为80℃;当矿渣的掺量不超过40%时,采用80℃蒸养或在60℃条件下延长蒸养时间均能使混凝土获得满意的拆模强度,当矿渣的掺量更大时,采用80℃蒸养能够使混凝土获得满意的拆模强度。含粉煤灰或矿渣的蒸养混凝土的抗氯离子渗透性明显优于纯水泥蒸养混凝土。(4)在80℃蒸养条件下,含大掺量矿渣的净浆中未观测到延迟钙矾石生成的现象,含大掺量粉煤灰的净浆中后期生成大量AFm。在80℃蒸养条件下的大掺量矿渣混凝土和大掺量粉煤灰混凝土的后期体积膨胀率与在60℃蒸养条件下的纯水泥混凝土的后期体积膨胀率比较接近。
[Abstract]:Steam high temperature curing is one of the main technical means to produce precast concrete members. The early hydration activity of fly ash and slag is low. The utilization ratio of steaming concrete is very low. The effect of fly ash and slag on the performance of steaming concrete is studied in this paper. The main conclusions are as follows: 1: 1) the length of static stop time is 1 h or 3 h. The influence of 6 h) on the hydration degree of the cementitious material, the compressive strength and the chloride ion permeability of the concrete at the later stage is small, and the static stop time is 3 h. It can make concrete obtain enough ability to resist the damage caused by steam and temperature rise.) prolonging the time of constant temperature and increasing the temperature of constant temperature can promote the hydration of composite cementing system more effectively than pure cement. When the steaming temperature reaches 70 鈩，

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