低品质骨料混凝土稠度改性试验研究

Experimental Research on Consistency Modif ication for Low Quality Aggregate Concrete

西北地区低品质粗砂混凝土存在工作性差、施工困难和实体结构易开裂的问题。本文选择了低成本的膏体温轮胶作为稠度改性剂,通过试验研究其对粗砂混凝土性能的影响,并在宝兰客运专线隧道衬砌混凝土中进行了应用。结果表明:膏体温轮胶具有保水增稠的特点,能够显著提高低品质骨料混凝土的塑性黏度,抑制混凝土离析、泌水和开裂,对混凝土长期力学性能、耐久性能无不利影响,用于西北地区粗砂混凝土施工具有明显的技术经济优势。

According to the poor workability,construction diff iculties and easily cracking of solid structure of low quality coarse sand concrete in northwest regions,welan gum paste with low cost was selected as consistency modif ier and its effect on properties of coarse sand concrete was studied by the experiments,which was applied in tunnel lining concrete engineering of Baoji-Lanzhou passenger dedicated line.The results show that welan gum paste has characteristics of water retention and thickening,could signif icantly improve plastic viscosity of low quality aggregate concrete,inhibit the segregation,bleeding and crack of concrete and have no adverse effect on the long-term mechanical properties and durability of concrete,which could be used in the construction of coarse sand concrete in northwest regions and has obvious technical and economic advantages.