Experimental study on the preparation of wood aggregate recycled concrete using waste wood and recycled fine aggregate from construction and demolition wastes

Abstract

As a renewable resource, wood has the advantages of a high strength-weight ratio, high yield and excellent thermal insulation. Meanwhile, the resource utilization of large quantities of waste wood, waste furniture and mixed wood generated by the demolition of old houses and the removal of building formwork are basically in a blank state. Therefore, in this study, construction solid waste—waste wood and recycled fine aggregate were used as coarse and fine aggregates to replace natural sand and gravel, respectively, and synergized with three cementitious materials (sulfoaluminate cement, portland cement and geopolymer cement) to prepare wood aggregate recycled concrete (WARC). Focus on the evolution law of basic property, thermal insulation property, mechanical property, shrinkage property, environmental and economic benefits of WARC. The results showed that the mechanical and shrinkage properties of WARC were deteriorated by using WA and recycled fine aggregate (RFA) instead of natural aggregates. The dry density of WARC was as low as 1770 kg/m3. The 28 d maximum compressive and flexural strength were 34.8 and 5.69 MPa, which were better than traditional C30 concrete. Compared with conventional concrete, WARC has excellent thermal insulation properties. The thermal conductivity was reduced by up to 81.9 % compared to traditional concrete, which would make WARC very promising for non-structural components (green insulated wall materials and precast wall panels, etc.). By calculating CO2 emissions and compressive strength-cost efficiency values, it was found that the WARC prepared with geopolymer cement could reduce CO2 emissions by 31.3 % while possessing good mechanical properties and economic benefits, making it the optimal cement-based material for preparing WARC.