王丕祥 郭环宇 周嫚

摘 要：为研究冻融损伤混凝土再生利用条件，推进寒区再生骨料在实际工程中的应用，本文以C30混凝土为基准，探讨级配形式、再生骨料取代率、高效减水剂掺量和砂率对再生混凝土抗压强度的影响规律，分析寒区服役28 a的旧桥再生混凝土和试验室旧试块再生混凝土的力学性能。试验结果表明：再生骨料混凝土配合比设计时应采用连续级配形式;增加再生骨料取代率和砂率对再生混凝土抗压强度有负影响;高效减水剂可以有效地提高再生混凝土力学性能;当再生骨料取代率相同时，旧桥再生骨料混凝土28 d抗压强度比旧试块再生混凝土低17.05%，寒区再生骨料应用时应注意控制取代率。

关键词：再生混凝土;冻融循环;再生骨料取代率;级配;高效减水剂;砂率

中图分类号：U444    文献標识码：A   文章编号：1006-8023（2021）04-0102-08

Study on the Mechanical Properties of Recycled Aggregate Concrete

in Cold Region

WANG Pixiang1， GUO Huanyu2， ZHOU Man1

（1.Department of Civil and Ocean Engineering， Guangdong University of Technology， Guangzhou 510006， China;

2.School of Civil Engineering， Northeast Forestry University， Harbin 150040， China）

Abstract：In order to study the conditions for the recycling of concrete damaged by freezing and thawing， and to promote the application of recycled aggregates in cold areas in practical projects， this paper used C30 concrete as a benchmark to discuss the gradation form， the replacement rate of recycled aggregates， the amount of superplasticizer and the influence of sand rate on the compressive strength of recycled concrete， and the mechanical properties of recycled concrete from old bridges that had been in service for 28 years in cold areas and recycled concrete from old test blocks in the laboratory were analyzed. The test results showed that： continuous gradation should be used in the design of recycled aggregate concrete mix ratio; increasing the replacement rate of recycled aggregate and sand ratio had a negative impact on the compressive strength of recycled concrete; superplasticizer could effectively improve the mechanical properties of recycled concrete; when the replacement rate of recycled aggregate was the same， the 28-day compressive strength of recycled aggregate concrete of the old bridge was 17.05% lower than that of recycled concrete of the old test block. When using recycled aggregate in cold areas， attention should be paid to controlling the replacement rate.

Keywords：Recycled concrete; freeze-thaw cycle; replacement rate of recycled aggregate; gradation; superplasticizer; sand rate

收稿日期：2021-03-07

基金项目：国家自然科学基金项目（51708092）

第一作者简介：王丕祥，硕士，副教授。研究方向为道路与桥梁工程。E-mail： wangpixiang@126.com

引文格式：王丕祥， 郭环宇， 周嫚. 寒区再生骨料对再生混凝土力学性能影响研究[J].森林工程，2021，37（4）：102-109.

WANG P X， GUO H Y， ZHOU M. Study on the mechanical properties of recycled aggregate concrete in cold region[J]. Forest Engineering，2021，37（4）：102-109.

0 引言

随着我国城乡经济建设的不断推进，棚户区改造、旧危建筑物的拆除等建设活动不断深入，建筑垃圾大量产生，导致土地被占用、自然环境被污染。据统计，我国每年产生的建筑垃圾达到20亿t，但有效利用率还不足5%，远低于发达国家水平[1-2]。另一方面，我国建筑行业的发展迅猛，造成号石与河砂等建筑材料严重短缺，同时在生产过程中也造成自然资源的极大破坏[3]。……