Preparation of solid-waste-based pervious concrete for pavement: A two-stage utilization approach of coal gangue. (14th February 2022)

• Record Type: Journal Article
• Authors: Wu, Changliang; Jiang, Wen; Zhang, Chao; Li, Jingwei; Wu, Shuang; Wang, Xujiang; Xu, Yimeng; Wang, Wenlong; Feng, Meijun
• Is Part Of: Construction & building materials. Volume 319(2022)
• Publication Date: 2022-02-14
• Subjects: Coal gangue -- High-strength pervious concrete -- Two-stage utilization -- Water permeability -- Environmental friendliness; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2021.125962
• Languages: English
• ISSNs: 0950-0618

Abstract

Graphical abstract: Highlights: A HSPC for permeable pavements was prepared by two-stage utilization of coal gangue. The prepared WSAC meeting Chinese standard for 52.5 N ordinary Portland cement. The HSPC has both high strength and high-water permeability. The HSPC prepared with WSAC and coal gangue is an environmentally friendly product. Abstract: As the most discharged solid waste in China; coal gangue (CG) occupies a considerable amount of land and severely pollutes the environment. Large-scale production, low added value of products, and lack of innovative disposal methods have lead to the difficult situation of effective utilization of CG. Therefore, it is very important to develop new ways to utilize CG on a large scale and with high-valued. This paper proposes a new method for reducing the environmental burden and realizing a high-value utilization of CG. The study was based on a two-stage utilization approach. Raw CG was first used to prepare solid-waste-based sulfoaluminate cement (WSAC). Then the prepared WSAC combined with self-ignited coal gangue (SCG) was used to prepare a high-strength pervious concrete (HSPC). The mechanical properties, mineral composition, and microstructure of the prepared WSAC clinker were analyzed. The results show that mortar from the prepared WSAC clinker had a reasonable mineral composition, well-developed crystals, and a compressive strength of 55.2 MPa at three days, which meets the standard for 52.5 N ordinary Portland cement. Furthermore, the influence of the water-binder (W/B) ratio, a ggregate-binder (A/B) ratio, and different SCG content on the performance of HSPC was studied. It was observed that the optimal HSPC was prepared when the W/B ratio and the A/B ratio were 0.22 and 4.0, respectively. Compared with traditional pervious concrete, the prepared HSPC has both high strength and high water permeability, and the obtained compressive strength is 34.8 MPa, a connected porosity of 19.80%, a water permeability of 7.95 mm/s, and a hardening density of 1930.8 kg/m 3 . An SCG content of 10%–20% was considered to the best dosage range for the preparation of HSPC. Furthermore, the freeze–thaw cycle analysis and abrasion resistance test indicated that HSPC with 10% SCG content has acceptable durability. Finally, the environmental impact of HSPC was evaluated through heavy-metal leaching tests, revealing that HSPC has a good curing ability on heavy metals and the leaching index was lower than the limit specified by the regulations, which reflects the environmental friendliness. Thus, this paper presents a low-cost and promising method for the resourceful utilization of CG and production of a sustainable pavement material. In addition, further research is needed before the application of this material to explore its durability and practicality in a specific environment.