Developing Lignite Pervious Concrete for Application in Pedestrian Walkways and Urban Runoff Treatment

Abstract

AbstractIn the present study, the mechanical characteristics and environmental aspects of lignite pervious concrete (LPC) in reducing stormwater pollution were investigated. Therefore, fine-grained lignite (0.6–1.2 mm) in various portions (up to 15% w/w of coarse aggregate) was added to the PC mixture. The workability, strength, cementitious paste thickness, and physical properties of LPC were examined for further application in urban areas with a focus on stormwater treatment. The statistical analysis of the results of ANOVA and visualization of the microstructure of LPC by means of scanning electron microscopy and energy-dispersive X-ray spectroscopy were also presented. The results showed that LPC is a sticky paste with no slump (0). Adding lignite also slightly reduced the compressive strength of LPC up to 23% lower than the control sample (13.8 MPa). In addition, the presence of lignite led to a considerable reduction in permeability (40%) and porosity (51%) compared to the control sample. It was also found that the increase in cementitious paste thickness resulted in an increase of the compressive strength, which was mainly concentrated between 0.3 and 1.8 mm. However, the performance of LPC in reducing stormwater contamination was promising. Sample L15, with the highest removal efficiency, reduced the chemical oxygen demand, total suspended solids, and turbidity up to 42.14%, 63.38%, and 67.24%, respectively, while no significant changes were observed in pH, total dissolved solids, and nitrate (NO3). In short, although adding lignite to PC caused a reduction in the strength and physical properties of LPC, its efficiency in reducing stormwater pollution is quite promising, and it is recommended for use in green spaces of urban areas. Graphical Abstract