碳化作用下混凝土的微生物表面处理

Microbial Surface Treatment of Concrete Under Carbonation

摘要:

利用脲解型微生物的成矿效应对碳化后的混凝土表面进行处理.测试了处理后混凝土的毛细吸水、抗水渗透和快速氯离子渗透性，并测定了表面接触角，综合分析了表面产物的微观形貌和组成.结果表明，碳化和微生物表面处理均能提高混凝土抗渗性能并降低吸水性，后者形成了粗大的方解石晶体并紧密附着在混凝土表面.碳化并不影响微生物成矿产物的晶型和形貌，然而是否碳化却对微生物表面处理后混凝土的吸水和抗渗行为有不同的作用规律.碳化后再进行微生物表面处理，混凝土表层吸水系数的降低幅度相比未碳化直接处理更高，其主要原因在于微生物表面处理能够改善碳化所带来的亲水问题.

关键词:混凝土; 碳化; 微生物; 表面处理; 耐久性

Abstract:

In this paper, the mineralization effects of ureolytic type microorganism were employed in the surface treatment of concrete after carbonation. The capillary water absorption, resistance to water permeation, and rapid chloride permeation (RCP) of concrete were tested after treatment. The contact angle of the surfaces was measured. The morphology and composition of the deposits were comprehensively studied. The results show that both carbonation and microbial surface treatment can increase the resistance to permeability while reducing the water absorption of concrete. Large calcite crystals, which tightly adhered to the concrete surfaces, are formed by microbial treatment. Carbonation has no impact on the crystalline and morphology of microbial precipitates. However, after microbial surface treatment, different effects are observed on the water absorption and permeation of concrete with or without carbonation. When microbial surface treatment is performed after carbonation, the range of further reduction in terms of water absorption coefficient is higher compared with the reduction by the treatment on uncarbonated concrete. The main reason for this phenomenon is that the degree of hydrophilicity of concrete after carbonation decreases after microbial surface treatment.

Key words:concrete; carbonation; microorganism; surface treatment; durability