生物炭混凝土性能及碳封存效益研究

The Performance and Carbon Sequestration of the Biochar Concrete

摘要: 碳封存是减缓全球变暖的关键技术。本研究利用不同质量分数生物炭替代普通水泥，制造生物炭混凝土，用C20强度标号混凝土作对照，比较分析生物炭混凝土基本性能及碳封存效益。当生物炭替代水泥为1%，生物炭混凝土强度超过对照9.77%；当替代水泥为5%，生物炭混凝土强度和对照强度相当；当替代水泥量为6%~30%时，生物炭混凝土强度下降，但仍然大于C20混凝土强度国家标准。生物炭混凝土补加水量、饱和吸水量随生物炭替代量增加而增加，坍落度和密度则下降。生物炭混凝土满足C20、C25和C30混凝土强度要求条件下，在全国新增建筑中推广，每年可封存4.95 × 10¹⁰ kg CO₂，在现有建筑改造中应用，可封存1.73 × 10¹² kg CO₂，相当于每年增加1.5‰我国现有森林面积。生物炭混凝土是封存碳的新方法，具有方法简单、成本低、封存时间长，能处理有机固体废弃物的特点。

Abstract: Carbon sequestration is a key technique mitigating the global warming. We used biochar to replace cement to make the biochar concrete in concrete production, and then compared the performance and carbon sequestration of the biochar concrete with C20 concrete. When 1% of cement was replaced by biochar, the strength of the biochar concrete increased by 9.77% compared with the control; When 5% of cement was replaced by biochar, the strength of the biochar concrete was similar to the control; When 6%~30% of cement was replaced by biochar, the strength of the biochar concrete decreased compared with the control, but the biochar concrete still met the national standards of the C20 concrete for the concrete strength. The addition of water for the production of the biochar concrete and the saturation water contents of the biochar concrete in-creased with increasing amount of biochar in the concrete, but slump constant and the apparent density of the biochar concrete decreased. If the biochar concrete that have met the demand of the strength of the C20, C25 and C30 concrete is applied to all constructing buildings in China, these buildings will be able to sequestrate 4.95 × 10¹⁰ kg CO₂; If the biochar concrete is applied for im-provement in structures and functions of the existing buildings, these existing buildings will be able to sequestrate 1.73 × 10¹² kg CO₂. The total sequestration of CO₂ by the application of the biochar concrete equals to 1.5‰ of the standard forest area in China. Biochar used to replace cement in concrete production is an innovative method of carbon sequestration. The biochar concrete has the advantages of easy operation, low cost, and long-time sequestration of carbon, and the production of the biochar concrete can consume a great amount of solid wastes.