废弃EPS材料高温改性影响机制及其混凝土力学性质研究

Study on Influence Mechanism of High Temperature Modification of Waste EPS Materials and Its Mechanical Properties

针对环境中EPS存在难降解、污染大的问题,拟对废弃EPS材料进行高温改性及再利用研究,分析高温对EPS密度、强度、微观结构等影响规律。结果表明:在50~90℃区间,其密度、强度无变化;在90~110℃区间,材料的密度、强度略有增加;随着温度的升高,微观结构表现为EPS材料表面的薄膜状微孔不断熔融,由原来孔壁<1μm、孔径60~120μm的大孔,热缩为120℃条件下的孔壁3~4μm、孔径为10~30μm的小孔,强度表现为115℃和120℃条件下较110℃提高5倍和7倍左右。再将不同温度改性、不同粒径的EPS颗粒分别与水泥浆以1∶4体积比制备混凝土试块,通过对其力学性能测试发现,随着改性温度的提高,混凝土的弹性模量逐渐提高,抗压强度显著增强,其中用粒径3 mm的EPS颗粒作骨料所制备的试块,从常温的5.24 MPa升高到120℃条件下的18.27 MPa,提升幅度最大,约2.5倍。

In view of the problem that EPS in the environment is difficult to degrade and pollute,this paper intends to study the high temperature modification and reuse of discarded EPS materials and the influence of high temperature on the density,strength and microstructure of EPS is analyzed.The results show that there is no change in density and strength between 50℃and 90℃and in the interval of 90℃to 110℃the density and strength of the material increase slightly.With the increase of temperature,the microstructure is expressed as the surface of EPS material.The film-like micro-pores are continuously melted,and the pores of the original pore wall less than 1μm and the pore diameter of 60-120μm are heat-shrinking to a pore size of 3-4μm and a pore diameter of 10-30μm at 120℃and the strength at 115℃and 120℃it is 5 and 7 times higher than 110℃.Then the EPS samples with different temperature modification and different particle size are prepared with cement slurry at a ratio of 1∶4 by volume.Through the test of its mechanical properties,it is found that,with the increase of the modification temperature,the elastic modulus of concrete is gradually increased,and the compressive strength is significantly enhanced.Among them,the test piece prepared by using 3 mm EPS particles as aggregates is increased from 5.24 MPa at normal temperature to 18.27 MPa at 120℃with the largest increase,about 2.5 times.