针对混凝土珊瑚骨料孔隙率大、骨料强度低、吸水率高的特点.采用PVA溶液对珊瑚骨料进行强化处理改性.研究了经不同浓度PVA溶液浸泡不同时间处理后的珊瑚骨料吸水率以及压碎指标,并使用改性后的珊瑚骨料拌制混凝土,测定其坍落度及立方体抗压强度.试验结果显示,珊瑚骨料平均吸水率降低了38％,最高降低达55％;压碎指标整体上随PVA浓度和浸泡时间先下降再回升;改性后珊瑚骨料拌制的混凝土7 d龄期强度可提升21％,28 d龄期强度提升可达16.85％.采用扫描电子显微镜(SEM)分析研究PVA改性珊瑚骨料的机理,结果显示改性后的珊瑚骨料表面形成致密的有机质薄膜,此薄膜可以使珊瑚骨料孔隙率明显降低,使骨料吸水率降低,同时可以改善骨料表面微观结构,降低其压碎指标,增加与水泥石的咬合强度,提高了拌合混凝土的强度.%Based on the large porosity, low strength, high water absorption of coral aggregate, the coral aggregate was modified by PVA solution. The water absorption and crush index of coral aggregate modified in different time and different PVA solution concentration were studied, and the concrete was prepared by using modified coral aggregate. Its slumps and cube compressive strength were determined. The experimental results showed that, the water absorption of modified coral aggregate reduced by an average of 38％, and the largest decline of water absorption was up to 55％;The crush index reduced first and then increased with increasing of PVA concentration and soaking time. The 7 d strength of modified coral aggregate concrete was up to 21％.The 28 d strength of modified coral aggregate concrete was up to 16.85％.The scanning electron microscopy (SEM) was used to study the mechanism of PVA modification of coral aggregate. The SEM test results showed that the modified coral aggregate surface formed a organic thin-film. This film can make coral aggregate porosity and water absorption decrease obviously. At the same time, it can improve the aggregate surface microstructure to reduce the crushing index, it is wrapped in the surface of the aggregate, which produces mechanical occlusion and enhances the strength of mixed concrete.
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