城市垃圾焚烧底渣再生微粉强度特性的实验研究

Experimental analysis of the mortar strength of regenerated powder from municipal solid waste incinerator bottom ash

为实现城市垃圾焚烧底渣的高效再生利用,进行了底渣及其再生微粉的物理、化学性质实验,采用不同比例底渣再生微粉替代水泥进行胶砂强度实验。结果表明:垃圾焚烧底渣再生微粉相比水泥材质更轻、颗粒更小、更均匀;再生微粉中以氧化物形式存在的Si、Al和Ca约占底渣总质量的70%,与水泥的化学成分组成类似,但SiO 2、Al 2O 3含量较高,而CaO含量较低。再生微粉内掺替代水泥的胶砂抗压、抗折强度均随替代比例的增加呈下降趋势;内掺30%时,再生微粉的强度活性指数可达55%以上,说明再生微粉具有一定的凝胶活性。此外,底渣再生微粉的掺加对胶砂早期强度的影响较小,随再生微粉掺量的增加,胶砂强度前期增长速度变慢,后期强度出现较大幅度的降低。

For efficient reuse of municipal solid waste incinerator bottom ash(MSWIBA),the physical properties and chemical composition test of regenerated powder from MSWIBA,colloidal mortar strength test by substituting cement of different proportion of regenerated powder were carried out.It is shown that the specific density of regenerated powder from MSWIBA is lighter and the particle size is smaller and more uniform than that of cement.The main chemical composition of the regenerated powder are Si,Al and Ca in the form of oxides,which account for about 70%of the total mass,which is similar to the chemical composition of cement,while the content of SiO2 and Al2O3 is little higher,and CaO is little lower.The compressive and flexural mortar strength show a decreasing trend with the increase of the substituting proportion.The strength activity index still exceeds 55%when the replacement proportion reaches 30%,which indicated that recycled micro-powder had certain gel activity.In addition,replace cement with the regenerated powder has slight effect on the early mortar strength than long-term strength,but the early intensity increased slower with the increase of replacement proportion,and long-term strength decreased significantly.