贝壳垃圾透水植生混凝土抗冻性能研究

Frost Resistance of Shell Waste Pervious Vegetation-growing Concrete

为研究我国北方沿海不同贝壳垃圾透水混凝土的抗冻性能,选取秦皇岛海域生长的贝壳,对其制备的透水植生混凝土进行了研究。采用慢冻法,以质量损失率、强度等评价指标,结合扫描电镜(SEM)、背散射电子成像(BSE)等微观试验,分别研究了厨余牡蛎垃圾、工厂牡蛎垃圾、厨余扇贝垃圾、工厂扇贝垃圾所制备透水混凝土的冻融耐久性。结果表明:工厂垃圾相对厨余垃圾具有更好的抗冻融性能和强度;掺入硅灰可降低碱度,显著提高抗压强度,但对抗冻融性能的提高有限,经微观分析与多因素比对,确定硅灰掺量为5%;扇贝垃圾制备的透水混凝土,其抗冻融耐久性优于牡蛎垃圾透水混凝土,扇贝壳微观致密的表层结构为其抗冻性能提供了积极作用。

The aim of this study is to investigate the frost resistance of pervious concrete added with different seashell wastes in northern coastal areas of China.The seashells from Qinhuangdao were selected to prepare pervious vegetation-growing concrete.The freeze-thaw durability of pervious concretes made from kitchen oyster waste,factory oyster waste,kitchen scallop waste and factory scallop waste were examined by slow freezing method with mass loss rate and strength as evaluation indexes in association with Scanning Electron Microscoke(SEM),Backscattered Electron Imaging(BSE)and other microscopic tests.Results revealed that(1)factory shell waste is of better freeze-thaw resistance and strength than kitchen shell waste.The incorporation of silica fume reduced the salinity while improving the compressive strength of shell pervious concrete,and enhancing the freeze-thaw resistance to a limited extent.Through microscopic analysis and multi-factor comparison,the content of silica fume is determined at 5%as the optimal.(2)Pervious concrete containing scallop waste boasts higher freeze-thaw durability than that containing oyster waste owning to its dense microscopic surface structure.