沼蛤侵蚀对混凝土的性能损伤试验研究

沼蛤侵蚀给混凝土带来的性能影响对防治措施的选择与决策具有重要的参考意义。对于受侵蚀1年的自制试件和受侵蚀20余年的现场芯样,本文采用浸泡增重法、压汞法、场发射环境扫描电镜法和热重法分别测试了有贝附着组和无贝对照组的表层吸水率、表层孔隙特征与孔径分布、表层形貌和成分变化,以及表层钙成分含量变化这4个指标,研究了沼蛤侵蚀混凝土前后以及侵蚀时间对微观性能的影响。定量分析表明:沼蛤附着侵蚀混凝土后,混凝土不同尺寸的孔隙均有增加,同时表观密度分别下降了13.5%(侵蚀1年)和19.5%(侵蚀20余年),表层吸水率分别增加了82%(侵蚀1年)和101%(侵蚀20余年),混凝土表面的铝元素、铁元素和锰元素大幅增加,钙元素尤其是碳酸钙流失严重,分别减少了41.7%(侵蚀1年)和82%(侵蚀20余年)。因此,沼蛤的侵蚀会造成混凝土的微观性能损伤,受侵蚀时间越长,性能损伤越严重。

Experimental study on concrete deterioration caused by Limnoperna fortunei fouling

The concrete performance changes caused by L. fortunei fouling has important reference significance on decision and selection of anti-fouling measures. To study the micro performance changes caused by L. fortunei fouling of the homemade specimens colonized by L. fortunei for one year and the cores from the zones colonized by L. fortunei for more than 20 years, indexes of water absorption, pore characteristics and distribution, surface morphology, element composition, and calcium minerals were compared by water absorption method,mercury intrusion method,environment scanning electron microscope method and thermogravimetry method. Quantitative analysis indicated that the pores of different sizes increased, resulting in bulk density decreased by 13.5% (colonized for one year) and 19.5% (colonized for more than 20 years) respectively, and water absorption increased by 82% (colonized for one year) and 101% (colonized for more than 20 years) respectively. Concentrations of aluminium,manganese and iron increased whereas calcium especially calcium carbonate concentration decreased by 41.7% (colonized for one year) and 82% (colonized for more than 20 years) respectively as a consequence of the mussel colonization. Therefore,the colonization of L. fortunei can cause micro-properties deterioration of concrete. The longer the colonization period,the worse the performance deterioration.