垃圾炭混凝土性能及生态效益研究

Performances and ecological impacts of concretecontaining municipal solid waste biochar

城市生活垃圾的急剧增加和水泥行业的高耗能、高污染带来了严重的环境问题。生物炭替代一定量水泥制备混凝土具有增强混凝土工作性能和强度的特性。研究用0%、1%、3%、5%、7%、9%、15%和20%质量百分比的垃圾生物炭(简称垃圾炭)替代水泥,制造胶砂和C35、C40混凝土,研究其工作性能和力学性能,采用SEM和FT-IR表征垃圾炭混凝土水化产物的微观结构,评价其生态效益。结果表明,垃圾炭替代水泥使水泥基材料的流动性下降;垃圾炭替代率为5%内时,力学性能增强,最高可提升混凝土10%的抗压性能和7%的劈裂抗拉性能;垃圾炭替代率在9%以内时,混凝土力学性能均优于规定的最低使用标准;垃圾炭替代率为15%~20%时,垃圾炭混凝土力学性能下降,但仍可作为低标号混凝土使用。垃圾炭混凝土若在全国城市推广,每年可处理垃圾约1.8亿吨,减少1.1亿吨CO2排放量,节约358亿元成本,生态效益和经济效益可观。

A rapid increase of municipal solid waste and high energy consumption of cement has brought serious environmental problems.Using biochar to replace cement for the production of concrete has a potential to enhance the performances and mechanical properties of concrete.In this study,0%,1%,3%,5%,7%,9%,15%and 20%of MSW biochar are used to replace cement by weight to produce mortar and C35,C40 concrete.The physical performances,mechanical properties and microstructures of the samples are analyzed by pressure test devices,SEM and FI-TR.The eco-economic benefits of concrete polularization are evaluated.The results show that the addition of biochar causes a little reduction on the flowability of mortar and concrete.When less than 5%cement is replaced by waste biochar,the compressive strength and the splitting tensile strength of the sample increase by 10%and 7%respectively.The mechanical properties are higher than the lower limit of national standard for concrete when replacement ratio is less than 9%.When the replacement ratio is 15%,the concrete could be used as low-grade concrete.The popularization of waste biochar to produce concrete will be able to dispose 180 million tons of solid waste,reduce 110 million tons of CO2 emissions and save 35.8 billion Yuan RMB in cost per year in China.