酸雨—荷载共同作用下废瓷砖再生骨料混凝土的性能

发布时间：2018-06-18 10:00

本文选题：酸雨 + 荷载　；参考：《湖南科技大学》2017年硕士论文

【摘要】：随着经济的快速发展,环境污染日趋严重,混凝土构件劣化加速。与此同时,砂石资源短缺,陶瓷废料不断增多;为减小酸雨-荷载作用影响及节约砂石资源,本文主要研究以废瓷砖为再生粗细骨料、以陶瓷粉为掺合料制备新型绿色的再生骨料混凝土,根据湖南省酸雨的特点以及建筑物承受荷载的一般情况,每组配合比混凝土分别在0.3fu和0.5fu作用后进行酸雨溶液干湿循环试验,研究废瓷砖再生骨料混凝土在酸雨-荷载共同作用下的性能影响,包括质量变化率、强度变化率、化学结合水含量、中性化深度和微观结构的观察。主要研究结果如下:在模拟酸雨侵蚀试验中,随着循环次数的增加,废瓷砖再生骨料混凝土的质量变化先增加后减小,且在循环至10次后开始呈下降趋势;原生碎石、废瓷砖再生粗骨料、废瓷砖再生粗细骨料混凝土的强度先增加后降低,中性化深度增大。随着陶瓷粉掺量的增加,废瓷砖再生骨料混凝土的强度损失增大,中性化深度减小,化学结合水含量减小。随着pH值的降低,废瓷砖再生骨料混凝土的强度降低,中性化深度增大,化学结合水含量减小。与模拟酸雨侵蚀试验相比,酸雨-荷载共同作用下,由于荷载的添加,废瓷砖再生骨料混凝土的质量变化率前期(循环至5次前)增长较快,后期(循环至10次后)减小更迅速,且先出现质量损失;强度变化率前期(循环至10次)减小,后期(循环10次以后)强度损失较快;中性化深度增加,化学结合水含量增加。在允许荷载范围内,随着荷载的增大,废瓷砖再生骨料混凝土的质量变化率前期(循环至5次)增大,后期(循环至10次后)减小;强度变化率减小,且循环至30次时为负值,相对于初始强度出现损失;中性化深度增大,化学结合水含量略有升高;微观结构中,针状AFt增多,且通孔较多,结构变得疏松,混凝土内部孔隙增多,酸雨溶液侵蚀后强度损失更大。根据已有酸雨侵蚀混凝土中性化深度预测模型文献,通过引入荷载影响系数及确定相关参数后,推导出了酸雨-荷载共同作用下废瓷砖再生骨料混凝土中性化深度预测模型,并将已有试验数据代入寿命预测模型得出计算值并将其与中性化深度实测值进行对比,计算值与试验结果吻合较好,该模型对酸雨-荷载共同作用下废瓷砖再生骨料混凝土中性化的预测有一定的参考价值。
[Abstract]:With the rapid development of economy, environmental pollution is becoming more and more serious, and the deterioration of concrete members is accelerated. In order to reduce the influence of acid rain and load and save the sand and stone resources, the waste ceramic tile is used as the recycled coarse aggregate. A new type of green recycled aggregate concrete was prepared with ceramic powder as admixture. According to the characteristics of acid rain in Hunan Province and the general situation of building bearing load, The dry and wet cycle tests of acid rain solution were carried out in each group of concrete after the action of 0.3fu and 0.5fu. The effects of acid rain and load on the performance of recycled aggregate concrete from ceramic tile were studied, including the rate of mass change and the rate of change of strength. Observation of chemically bound water content, neutralization depth and microstructure. The main results are as follows: in the simulated acid rain erosion test, with the increase of cycle times, the quality change of recycled aggregate concrete of ceramic tile increases first and then decreases, and then decreases after 10 cycles. The strength of recycled coarse aggregate concrete increased first and then decreased, and the neutralization depth increased. With the increase of ceramic powder content, the strength loss, neutralization depth and chemically bound water content of recycled aggregate concrete increased. With the decrease of pH value, the strength of recycled aggregate concrete decreases, the neutralization depth increases, and the water content of chemically bonded concrete decreases. Compared with the simulated acid rain test, under the combined action of acid rain and load, the mass change rate of recycled aggregate concrete of waste ceramic tile increases faster (from the cycle to 5 times) because of the addition of load. In the later period (cycle to 10 times), it decreased more rapidly, and appeared mass loss first; the intensity change rate decreased in the early stage (cycle to 10 times), and in the later period (after 10 cycles) the loss of strength was faster; the neutralization depth increased and the content of chemically bound water increased. Within the allowable load range, with the increase of the load, the mass change rate of recycled aggregate concrete increases at the early stage (up to 5 cycles), decreases at the later stage (after 10 cycles), and decreases in the strength change rate, and is negative at 30 cycles. Relative to the initial strength, loss occurs; the neutralization depth increases, the chemically bound water content slightly increases; in the microstructure, the acicular AFT increases, and there are more through pores, the structure becomes loose, and the internal porosity of concrete increases. The strength loss of acid rain solution is greater after erosion. According to the existing literature on the prediction model of neutralization depth of acid rain corroded concrete, a prediction model of neutralization depth of recycled aggregate concrete of waste ceramic tile under the combined action of acid rain and load is derived by introducing load influence coefficient and determining relevant parameters. The calculated values are compared with the measured values of neutralization depth, and the calculated values are in good agreement with the experimental results. The model can be used to predict the neutralization of recycled aggregate concrete under the combined action of acid rain and load.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

【参考文献】