多孔相变钢渣骨料大体积混凝土试验研究

发布时间：2018-07-09 22:23

  本文选题：多孔钢渣 + 相变材料　； 参考：《西安建筑科技大学》2015年硕士论文

【摘要】：大体积混凝土结构中由于内外温差较大而引起的温度裂缝问题一直是土木工程质量的顽症之一。温度裂缝一般都是贯穿裂缝,严重影响构筑物的安全使用。目前对防治大体积混凝土温度裂缝的研究中,主要是从内因和外因两个方面来考虑。本文从内因考虑,将相变材料加入到大体积混凝土以降低其中心温度和延缓中心温度峰值的到来时间。相变储能材料具有储能密度大、吸放热过程近似等温的特点,可以从内部因素考虑降低大体积混凝土的中心温度。本课题采用石蜡作为相变材料,多孔钢渣作为载体吸附相变材料,采用真空吸附法制备多孔相变钢渣骨料,分析和测试了多孔相变钢渣骨料的热性能。然后利用多孔相变钢渣骨料制备多孔相变钢渣混凝土,测试多孔相变钢渣混凝土和多孔钢渣混凝土的力学性能和热性能,采用扫描电子显微镜(SEM)分析多孔钢渣混凝土和多孔相变钢渣混凝土的骨料-水泥石界面微观形貌。最后,以实测工程中建筑物的基础筏板为几何模型建立有限元数值模型,采用有限元分析软件MIDAS Civil模拟分析了多孔相变钢渣大体积混凝土和多孔钢渣大体积混凝土的温度场以及中心温度的差异。实测基础筏板工程掺入矿物掺合料降低大体积混凝土的内部温度,对比分析了实测数据和多孔相变钢渣大体积混凝土数值模拟结果。研究结果表明,多孔钢渣对石蜡的质量吸附率为7.75%,且吸附率会随着粒径的减小而增加,热性能测试和分析表明多孔相变钢渣骨料具有较好的储能作用。温升实验中多孔相变钢渣混凝土的中心温度峰值比普通钢渣混凝土的中心温度峰值降低了4.9℃,延迟了60min。多孔相变钢渣混凝土的抗压强度低于多孔钢渣混凝土的抗压强度。骨料-水泥石界面的微观分析表明多孔相变钢渣混凝土的界面不够致密,有细小的缝隙。数值分析结果表明掺相变材料的控温技术与掺矿物掺合料的控温技术在降低大体积混凝土的温度方面取得了相近的效果。
[Abstract]:The problem of temperature cracks in mass concrete structures caused by large internal and external temperature difference has been one of the persistent problems of civil engineering quality. Temperature cracks are generally through cracks, which seriously affect the safe use of structures. At present, the research on preventing and curing temperature cracks of mass concrete is mainly considered from two aspects: internal cause and external factor. In order to reduce the central temperature and delay the arrival time of the peak value of the center temperature, the phase change material is added to the mass concrete in terms of internal causes. The phase change energy storage material has the characteristics of high energy storage density and approximately isothermal heat absorption and exothermic process, so the central temperature of mass concrete can be reduced by considering the internal factors. In this paper, paraffin is used as phase change material, porous steel slag as carrier to adsorb phase change material, and vacuum adsorption method is used to prepare porous phase change steel slag aggregate. The thermal properties of porous phase change steel slag aggregate are analyzed and tested. Then the porous phase change steel slag concrete was prepared by porous phase change steel slag aggregate, and the mechanical and thermal properties of porous phase change steel slag concrete and porous steel slag concrete were tested. The interface morphology of porous steel slag concrete and porous phase change steel slag concrete was analyzed by scanning electron microscope (SEM). Finally, the finite element numerical model is established by taking the foundation raft of the building in the actual engineering as the geometric model. The temperature field and center temperature difference of porous phase change steel slag mass concrete and porous steel slag mass concrete are simulated by the finite element analysis software Midas Civil. The internal temperature of mass concrete was reduced by adding mineral admixture in the engineering of raft slab. The measured data and numerical simulation results of porous phase change steel slag mass concrete were compared and analyzed. The results show that the mass adsorption rate of porous steel slag for paraffin wax is 7.75 and the adsorption rate will increase with the decrease of particle size. The thermal performance test and analysis show that porous phase change steel slag aggregate has better energy storage function. In the experiment of temperature rise, the central temperature peak of porous phase change steel slag concrete is 4.9 鈩，

本文编号：2110894