再生PET塑料骨料砂浆耐久性试验研究

Experimental Study on Durability of Recycled PET Plastic Aggregate Mortar

利用废弃聚对苯二甲酸乙二醇酯(PET)塑料制备再生PET塑料骨料(RPA),利用RPA取代天然砂制备再生PET塑料骨料砂浆(RPAM),研究RPA取代率对RPAM耐久性的影响,采用X射线衍射(XRD)分析RPA对砂浆水化产物的影响,利用扫描电镜(SEM)和能谱仪(EDS)分析砂浆微观结构和界面化学元素比例。结果表明:RPAM的毛细吸水、氯离子渗透、碳化深度和干燥收缩均随RPA取代率增加而增加,RPAM的耐久性随RPA取代率增加而降低。RPAM力学性能与耐久性能归一化结果显示,RPA的最佳掺量为14.8%~19.7%。片状RPA阻碍水泥浆体内部的水化反应,使其与水泥浆体之间界面过渡区(ITZ)较薄弱,浆体内部微孔隙及薄弱界面增多,RPAM耐久性降低。

The recycled PET plastic aggregate(RPA) was prepared by waste polyethylene terephthalate(PET) plastic.The recycled PET plastic aggregate mortar(RPAM) was prepared by replacing natural sand with RPA.The effect of RPA substitution rate on the durability of RPAM was studied.The effect of RPA on the hydration products of RPAM was analyzed by X-ray diffraction(XRD).The microstructure of RPAM and the proportion of interfacial chemical elements were analyzed by scanning electron microscopy(SEM) and energy dispersive spectrometer(EDS).The results show that the capillary water absorption,chloride ion penetration,carbonation depth and drying shrinkage of RPAM are increased with the increasing of RPA substitution rate.The durability of RPAM is decreased with the increasing of RPA substitution rate.The normalized results of mechanical properties and durability of RPAM show that the optimum content of RPA is14.8%~19.7%.The addition of flake RPA hinders the hydration reaction inside the cement paste,so that the interfacial transition zone(ITZ) between RPA and the cement paste is weak,the micro-pores and weak interfaces inside the cement paste increase,and the durability of RPAM decreases.