在PCCP行业大发展时期要高度重视产品质量

Pay High Attention to the Products Quality During the Great Development Period of PCCP Industry

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关键词:

陶粒类型;自收缩;陶粒混凝土;内部湿度;吸水返水特性

Key words:

Ceramsite type; Autogenous shrinkage; Ceramsite concrete; Internal humidity; Water absorption and desorption property

刊期:

2011年第9期

DOI:

文章编号:

1000-4637(2011)09-01-03

基金项目:

作者:

张树凯

单位:

中国混凝土与水泥制品协会,北京 100831

摘要

摘   要:对不同类型陶粒在陶粒混凝土中的吸水返水过程、水泥石孔径分布、陶粒混凝土的内部湿度与自收缩进行了测试。研究结果表明:陶粒经过预湿处理后,吸水率大的陶粒在陶粒混凝土中的返水能力比吸水率小的陶粒强;普通混凝土的有效水灰比和内部相对湿度最小,吸水率小的陶粒轻骨料混凝土居中,吸水率大的陶粒轻骨料混凝土最大;对于经过24h预湿处理的粗骨料,在水泥石中孔径小于50nm的累计孔径方面,吸水率大的陶粒轻骨料混凝土最小,吸水率小的陶粒轻骨料混凝土居中,普通混凝土最大;混凝土自收缩是有效水灰比和粗骨料约束程度共同作用的结果,吸水率大的陶粒轻骨料混凝土自收缩最小,普通混凝土的居中,吸水率小的陶粒轻骨料混凝土自收缩最大。

Abstract: The water absorption and desorption process of different type ceramsites embedded in ceramsite concrete, the pore size distribution of hardened cement paste in ceramsite concrete, the ceramsite concrete internal humidity and the autogenous shrinkage of ceramsite concrete are tested. The study results reveal that in ceramsite concrete, the water desorption property of higher water absorption ceramsites is stronger than that of lower water absorption ceramsites after 24h prewetting processing. The effective water-cement ratio and relative humidity of the ceramsite concrete with higher water absorption ceramsites is higher than that of the ceramsite concrete with lower water absorption ceramsites, and the relative humidity of the ordinary concrete is the lowest. With 24h prewetting processing of coarse aggregates, the cumulative pore size(< 50nm) of hardened cement paste of the ceramsite concrete with higher water absorption ceramsites is lower than that of the ceramsite concrete with lower water absorption ceramsites, and ordinary concrete is the largest. Concrete autogenous shrinkage is the result of the joint action of the effective water-cement ratio and constraint degree of coarse aggregates. The autogenous shrinkage of ordinary concrete is larger than that of the ceramsite concrete with higher water absorption ceramsites, but smaller than that of the ceramsite concrete with lower water absorption ceramsites.

结论

PCCP由于其特殊的性能和优点,目前已受到国内外行业人士的广泛关注。尽管我国生产使用PCCP起步较晚,但目前已经取得了历史性突破。特别是南水北调中线京石段应急供水工程选用DN4000 PCCP铺设成功,标志着我国PCCP的生产技术水平、铺设安装水平、装备水平已达到世界先进水平。但PCCP产业大发展的同时,也存在一些问题。市场竞争激烈,使企业经营更加困难;国内现有PCCP生产线已能满足目前建设需要,原则上不应再新建PCCP生产线;其产品质量和铺设安装质量也有待进一步提高。我国应用PCCP以来,发生了几起质量事故,应引起PCCP行业的高度重视。此外,根据2011年“一号文件”,未来5~10年国家大力发展水利建设,也是PCCP行业发展的最佳时机。PCCP行业需加强企业管理,提高产品质量,努力生产出优质的产品,以满足国家建设的需要。

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