废弃混凝土中砂浆组分的性能及利用研究

发布时间：2018-06-10 03:18

本文选题：废弃混凝土 + 废砂浆粉　；参考：《广东工业大学》2015年硕士论文

【摘要】：中国已经步入了城镇化的加速阶段,众多旧有建筑物的拆除与改造必然产生大量废弃混凝土。如果废弃混凝土随意占地堆放,既会造成严重的环境污染,又是巨大的资源浪费。近年来人们对废弃混凝土的再生利用局限于作为再生骨料使用,针对废弃混凝土中废砂浆组分的利用研究也较少。从原料成本上看,废砂浆是废弃混凝土中成本较高的“精华”,作为再生骨料利用并没充分体现其价值；且附着废砂浆的再生骨料性能较差,制造再生骨料过程中大量的微细颗粒被丢弃。但废砂浆块易磨性能好,特别是经过煅烧热处理后更容易粉磨,磨细耗能相对较低。根据用于水泥混合材的细度要求,废砂浆的这种特点为其作为水泥混合材利用带来很大的可能性。为了提高废砂浆的回收利用价值和克服再生骨料的缺陷,本文对如何高效分离及球磨粉碎废弃混凝土中的砂浆组分进行机理分析。在实验基础上,获得废砂浆粉的基本物理性能,以及化学激发剂改性及高温煅烧方法两种方法对废砂浆粉混合水泥力学性能改善的影响,找到了充分激发废砂浆粉活性获取高活性废砂浆粉的方法。本文主要研究内容及成果如下：(1)通过对废弃混凝土中砂浆组分分离及球磨粉碎机理的分析,提出了界面过渡区原理,研究机械球磨粉碎和煅烧热处理对废砂浆组分物理化学结构的改变,以及该改变对废砂浆组分的回收效率和粉磨性能的影响。得出延长球磨时间t、提高研磨介质质量m和高度h,以及高于500℃煅烧热处理的方法都有利于废砂浆的分离收集和磨细；且在500℃-600℃这一温度区间煅烧后的粗骨料性能保持良好,可回收高品质的再生骨料的结论。(2)研究了废砂浆粉替代部分水泥对混合水泥标准稠度需水量、流动度和强度等性能的影响。实验结果表明废砂浆粉吸水率较大,细度和掺量都会影响强度,0.08mm筛余率为2.7%的废砂浆粉活性指数可达77%。混合水泥折压比有所增长,材料延性较好。(3)研究了利用化学激发剂对废砂浆粉进行改性。结果表明掺0.5%FDN-A减水剂对掺30%废砂浆粉混合水泥胶砂流动度的改性效果较好,FDN-A减水剂、二水石膏、硅酸钠、硫酸钠都有利于提高废砂浆粉混合水泥的强度,改性效果较好,并得出各化学激发剂的最佳掺量及最优化配方。(4)研究了不同煅烧温度对废砂浆块易磨性、流动度的影响以及废砂浆粉的活性激发效果。实验表明,经600℃热处理,掺30%废砂浆粉混合水泥的28天强度增长了3.01MPa,结合分离废弃混凝土中砂浆组分的最佳温度在500℃～600℃这一结论,确定了600℃是分离和激发废砂浆活性的最佳温度。(5)基于化学激发剂最优化配方,对经过600℃热处理的热活化废砂浆粉进行化学激发剂改性。当废砂浆粉掺量为20%、30%时,混合水泥的28天抗压强度可达48.61MPa和45.03MPa,基本符合42.5水泥强度等级要求,当掺量为40%、50%时,也能配制出基本符合32.5强度等级要求的混合水泥,当掺量更高时可作为低强度等级混合水泥使用。
[Abstract]:China has stepped into the accelerating stage of urbanization. The demolition and reconstruction of many old buildings will inevitably produce a large number of waste concrete. If the waste concrete is stacked at random, it will cause serious environmental pollution and huge waste of resources. In recent years, the regeneration and utilization of abandoned coagulant soil is limited to the regenerated aggregate in recent years. There is less research on the utilization of waste mortar components in waste concrete. From the cost of raw materials, waste mortar is the "essence" of high cost in waste concrete. As recycled aggregate, it does not fully reflect its value; and the recycled aggregate of waste mortar is poor, and a large number of fine particles are made in the process of producing recycled aggregate. Discarded. But the waste mortar blocks are easily grindable, especially after calcined heat treatment. The grinding energy is relatively low. According to the requirements for the fineness of the cement mixture, the characteristics of the waste mortar will bring a great possibility for its use as a cement mixture. In order to improve the recycling value of the waste mortar and overcome the regenerated bone On the basis of the experiment, the basic physical properties of the waste mortar powder, and the effect of the two methods of chemical activator modification and high temperature calcination on the mechanical properties of the mixed cement cement are found, and the full excitation is found. The main contents and results of this paper are as follows: (1) the principle of interface transition zone was put forward by analyzing the separation of mortar components and grinding mechanism in waste concrete, and the change of physical and chemical structure of waste mortar components was studied by mechanical milling and calcining heat treatment. And the effect of the change on the recovery efficiency and the grinding performance of the waste mortar components. It is concluded that the prolongation of the ball milling time t, the improvement of the quality of the grinding medium M and the height h, and the calcining heat treatment above 500 centigrade are beneficial to the separation and refinement of the waste mortar, and the coarse aggregate performance after the calcined at the temperature range of 500 degrees centigrade is good. Well, the conclusion of high quality recycled aggregate can be recovered. (2) the effect of waste mortar powder instead of part cement on the water requirement, fluidity and strength of the standard consistency of mixed cement is studied. The experimental results show that the water absorption rate of the waste mortar powder is larger, the fineness and admixture will affect the strength, and the activity index of the waste mortar powder with the residual rate of 2.7% 0.08mm is up to 7. The ratio of 7%. mixed cement increased and the material ductility was better. (3) the modification of waste mortar powder was studied using chemical activator. The results showed that the modified effect of 0.5%FDN-A admixture on the mixing of cement mortar mixed with 30% waste mortar powder was better, FDN-A water reducing agent, two water stone, sodium silicate and sodium sulphate were all beneficial to the improvement of waste mortar powder. The strength of mixed cement has good modification effect, and the optimum dosage and optimum formula of each chemical activator are obtained. (4) the effect of different calcination temperature on the grindability, the fluidity and the activation effect of the waste mortar powder are studied. The experiment shows that the strength of the mixed cement with 30% waste mortar powder increases at the temperature of 600 degrees centigrade. 3.01MPa, combining the conclusion that the optimum temperature of mortar components in separated concrete is 500 to 600 degrees C, the optimum temperature for separating and stimulating the activity of waste mortar is determined at 600. (5) based on the optimum formula of chemical activator, the chemical activator is modified by the heat activated waste sand pulp after 600 C heat treatment. When the amount is 20%, 30%, the 28 day compressive strength of the mixed cement can reach 48.61MPa and 45.03MPa, which basically meets the requirement of 42.5 cement strength grade. When the amount of mixing is 40% and 50%, it can also make up the mixed cement which basically meets the requirements of the 32.5 strength grade, and can be used as a low strength grade mixed cement when the amount is higher.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528

【参考文献】