WANG Kehan^a, LI Ying^b, BAI Hualei^a, DAI Dahu^a

(a. School of Civil Engineering, b. Qinghai Key Laboratory of Building Energy Saving Materials and Engineering Safety, Qinghai University, Xining 810016, China)

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

Get Citation：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

Received：2023-03-02,Revised：2023-05-22,Online：2023-08-03 09：29。

Funding Project：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。

First Author：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。

Corresponding Author：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。

CLC No：TU528; TB4

Type Code：A

Serial No：1008-5548(2023)05-0023-10