Investigation of the mechanical and shrinkage properties of plastic-rubber compound modified cement mortar with recycled tire steel fiber. (6th June 2022)

• Record Type: Journal Article
• Authors: Su, Peifeng; Dai, Qingli; Li, Miaomiao; Ma, Yunxiang; Wang, Jiaqing
• Is Part Of: Construction & building materials. Volume 334(2022)
• Publication Date: 2022-06-06
• Subjects: Cement mortar -- Plastic-rubber compound -- Recycled steel fiber -- Mechanical properties -- Drying shrinkage -- Distinct element method -- Crack propagation; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2022.127391
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Cement mortar with plastic-rubber compound and fiber were prepared and tested. Recycled steel fibers improved the mechanical properties of mortar samples. Plastic-rubber compound reduced early-age shrinkage due to its water containment. Crack initiation and propagation were analyzed with SEM imaging and DEM model. Abstract: To facilitate the recycling of waste solids in cement-based materials, plastic-rubber (PR) compound modified mortar (PRM) samples and recycled steel fiber (RSF)-reinforced plastic-rubber modified mortar (PRSRM) samples were prepared and tested to evaluate their mechanical and drying shrinkage properties. PR compound particles, with a mesh size of #8, replaced the natural aggregates with four volume percentages: 2%, 5%, 7.5%, and 10%. The fiber was added with a constant volume fraction of 0.2%. Accordingly, control mortar, PRM mortar with different PR replacement ratios, and PRSRM mortar with RSF were prepared and tested. A numerical splitting tension test model was also established based on the two-dimensional Distinct Element Method (DEM) to investigate the crack initiation and propagation mechanism of the PRM samples. The mechanical test results indicated that the addition of RSF enlarged the compressive strength by 14–27% PRM samples. Meanwhile, both PR and RSF improved mortar flexural behavior by increasing the fracture energy. The SEM image of a fracture surface and DEM simulation showed the crack propagation path was changed by PR particles due to its lower stiffness. Meanwhile, the 7-days drying shrinkage length change was reduced by about 25% due to the PR's porous structure and water-retaining ability. Overall, the sustainable material design with the combination of PR and RSF would promote the full-recycling of waste tires in cement-based materials.