Experimental Study On Cement Stabilized MSWI-BA Macadam Base Based On Crack Resistance

Incineration of waste-to-energy technology is widely used in the treatment of municipal solid waste.As municipal solid waste incineration-bottom ash（MSWI-BA）,the product of municipal solid waste treatment,not only has a large output,but also belongs to general waste,so how to effectively use MSWI-BA for resource utilization is of great significance.This paper mainly studies the feasibility of using MSWI-BA instead of natural aggregate to improve the crack resistance of cement stabilized macadam base.By analyzing the basic material properties,chemical composition and micro-morphology of the MSWI-BA,this paper uses different particle sizes and different amounts of MSWI-BA to prepare cement stabilized macadam base samples to study the mechanical properties and shrinkage properties of the base samples.In addition,this paper is based on the evaluation index of anti-cracking performance proposed by domestic scholars,comprehensively considering the design and proposing the coefficient of anti-cracking evaluation index Ac.And draw the following conclusions:（1）The surface of MSWI-BA is uneven and porous,which has the characteristics of low density,low strength,high moisture content and high water absorption.SEM-EDS analysis shows that MSWI-BA belongs to CaO-SiO2-Al₂O₃-Fe₂O₃ system,which shows that there are certain pozzolanic activity and cementitious activity in MSWI-BA.（2）The base is designed to be of skeleton dense structure,the cement dosage is 4%,the mass proportion of aggregate in each grade is 19.0-31.5mm:9.5-19.Omm:4.75-9.5mm:2.36-4.75mm:0-2.36mm=23:26:19:12:20,MSWI-BA is divided into grade A（0-2.36mm）,grade B（2.36-4.75mm）and grade C（4.75-9.5mm）.In addition,each grade of MSWI-BA can be replaced with limestone gravel aggregates and mixed into the base mixture according to the mass ratio of 0%,30%and 50%.（3）The mechanical performance tests show that the use of MSWI-BA instead of natural limestone gravel aggregates into the cement stabilized macadam base can reduce the unconfined compressive strength and cleavage strength,but they all still meet the requirements of the code.Moreover,the more MSWI-BA is added,the more influence it has on the strength of base course.Regression curve analysis shows that the products of MSWI-BA,cement and aggregate can promote the rapid growth of the strength of the base layer.The more the MSWI-BA is added,the faster the growth rate of the mechanical strength of the base layer.（4）The dry shrinkage test indicates that the addition of MSWI-BA not only effectively reduces the shrinkage strain of the base layer,but also reduces the sensitivity of the base layer to water.The temperature shrinkage text indicates that MSWI-BA can not only effectively reduce the temperature shrinkage strain of the base layer,but also slow down the deformation of the base due to the solid-phase shrinkage and liquid-phase shrinkage at different temperatures.（5）Based on the existing evaluation indexes,the paper proposes the shrinkage and crack resistance comparison indexes βd and βt,and the crack resistance evaluation index coefficient Ac.The smaller the comparative index value,the better the shrinkage performance of the base layer,and the larger the value of the comprehensive evaluation index coefficient,the better the crack resistance of the base layer collection.According to the comprehensive shrinkage crack resistance comparison index and crack resistance evaluation index coefficient Ac,the best mix proportion is recommended:the MSWI-BA dosage is 50%,the particle size is 0-2.36mm or 4.75-9.5mm.In summary,proper addition of MSWI-BA can effectively improve the shrinkage performance of the cement stabilized crushed stone base and the crack resistance of the base.