不同硫酸盐溶液对再生微粉混凝土抗压强度的影响

Effect of different sulfate solutions on compressive strength of recycled micronized concrete

王珂涵^a, 李滢^b, 白花蕾^a, 代大虎^a

（青海大学a. 土木工程学院, b. 青海省建筑节能材料与工程安全重点实验室, 青海西宁810016）

引用格式：王珂涵, 李滢, 白花蕾, 等. 不同硫酸盐对再生微粉混凝土抗压强度的影响[J]. 中国粉体技术, 2023, 29(5): 23-32.

WANG K H, LI Y, BAI H L, et al. Effect of different sulfate solutions on compressive strength of recycled micronized concrete[J]. China Powder Science and Technology, 2023, 29(5): 23-32.

DOI：10.13732/j.issn.1008-5548.2023.05.004

收稿日期：2023-03-02,修回日期：2023-05-22，在线出版时间：2023-08-03 09：29。

基金项目：国家自然科学基金项目,编号:51668052;青海省基础研究计划项目,编号:2023-JZ-725。

第一作者简介：王珂涵(1998—),男,硕士研究生,研究方向为再生混凝土。E-mail: wkh9735@163.com。

通信作者简介：李滢(1973—),教授,硕士,研究方向为建筑垃圾再生利用。E-mail: liying.qh@163.com。

摘要：为了研究不同硫酸盐环境对再生微粉混凝土耐久性能的影响, 将再生微粉以不同取代率取代水泥后制备的混凝土分别半浸泡于质量分数为10%的Na2SO4溶液、质量分数为10%的MgSO4溶液中, 考察再生微粉混凝土抗压强度随泡时间的变化规律, 探究再生微粉混凝土在不同硫酸盐溶液中抵抗硫酸盐侵蚀的性能及再生微粉混凝土的劣化机理。结果表明: 当再生微粉的取代率为20%时, 再生微粉混凝土抗硫酸盐侵蚀能力最强, 再生微粉混凝土半浸泡Na2SO4溶液180 d后, 上部抗压强度最低为40.44 MPa。再生微粉混凝土半浸泡于MgSO4溶液180 d后,上部抗压强度最低为47.81 MPa。再生混凝土浸泡于硫酸钠溶液中主要产生物理破坏和化学破坏,浸泡于硫酸镁溶液中主要产生化学破坏;物理破坏主要是硫酸钠结晶的生成,化学破坏主要产生膨胀性物质生成,导致混凝土破坏。

关键词：硫酸盐侵蚀; 再生微粉混凝土; 半浸泡; 劣化机理

Abstract：In order to study the effect of different sulfate environments on durability performance of recycled micronized concrete, the concrete prepared by replacing cement with recycled micronized powder at different substitution rates was semi-soaked in Na2SO4 solution with a mass fraction of 10% and MgSO4 solution with a mass fraction of 10%, respectively, to investigate the resistance of recycled micronized concrete to sulphate attack in different sulphate solutions and the deterioration mechanism of recycled micronized concrete. The durability of recycled micronized concrete against chemical attack in different sulfate solutions and the deterioration mechanism were investigated. The results show that when the replacement ratio of recycled micronized concrete is 20%, the recycled micronized concrete has the strongest resistance to sulfate attack, and the compressive strength of the upper part of the recycled micronized concrete is 40.44 MPa after 180 d of semi-soaking in Na2SO4 solution, and the compressive strength of the upper part of the recycled micronized concrete is 47.81 MPa after 180 d of semi-soaking in MgSO4 solution. Recycled concrete immersed in sodium sulphate solution causes mainly physical damage and chemical damage. Immersed in magnesium sulphate solution causes mainly chemical damage. Physical damage is mainly the generation of sodium sulphate crystals and chemical damage is mainly the generation of expansive substances, resulting in concrete damage.

Keywords：sulfate attack; recycled micronized concrete; semi immersion; deterioration mechanism

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