FAN Y H, TAI W S , WANG P H, et al．Creep performance of methyl methacrylate composite modified recycled coarse aggregate concrete[J]. Journal of Henan Polytechnic University( Natural Science)，doi:10.16186/j.cnki.1673-9787.2025090043.

doi: 10.16186/j.cnki.1673-9787.2025090043

Received： 2025-09-25

Revised： 2026-01-13

Online： 2026-09-14

Creep performance of methyl methacrylate composite modified recycled coarse aggregate concrete (Online)

Fan Yuhui1，2，Tai Wusheng1，Wang Penghui1，Xu Ping1

1. School of Civil Engineering, Henan Polytechnic University, Jiaozuo 454003, Henan，China;

2. Henan Province Engineering Laboratory for Eco-architecture and Built Environment, Henan Polytechnic University, Jiaozuo 454003, Henan，China

Abstract: Objectives In order to reduce the creep of recycled coarse aggregate concrete (RAC), this study investigates the effect of creep characteristics of old mortar in recycled coarse aggregates (RCA) on the creep behavior of RAC. The research focuses on achieving low creep in RAC by reducing the creep of the old mortar within the RCA．Methods First, a composite treatment method involving cement pre-coating followed by methyl methacrylate (MMA) impregnation and polymerization was used to strengthen the RCA. This process aimed to fill micro-cracks and larger pores in the RCA, thereby enhancing its mechanical properties and reducing its creep deformation. Subsequently, through creep testing of RAC and an analysis of the influence of RCA on concrete creep, a creep prediction model for RAC was developed. This model incorporates the creep and mechanical properties of the coarse aggregates. Results After MMA composite modification, the properties of RCA exhibited significant improvements: water absorption decreased by 70.3%, the crushing index was reduced by 42.0%, and total porosity diminished by 85.5%. A detailed pore structure analysis revealed reductions of 80.8% in harmless pores, 96.9% in less harmful pores, 88.6% in harmful pores, and 67.5% in more harmful pores. The use of MMA-modified RCA effectively reduced the creep of RAC. At replacement ratios of 33%, 66%, and 100%, the 240-day creep degree of the RAC with modified-RCA was lowered by 15.91%, 20.03%, and 31.19%, respectively, compared to conventional RAC. Furthermore, the developed creep prediction model, which incorporates the creep and mechanical properties of the coarse aggregates, provided accurate predictions for the creep behavior of RAC. Conclusions MMA composite modification can effectively enhance the mechanical properties and improve the pore structure of RCA, thereby reducing the creep of RAC．

Key words: Recycled coarse aggregate; old mortar; composite modification; recycled coarse aggregate concrete; creep