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In this paper, a novel pervious concrete (PC) has been proposed, which combines a high-strength self-compacting concrete matrix with artificial pore channels, to prepare a novel self-compacting recycled pervious concrete (NSRPC) with vertically and uniformly distributed pore channels. Then, an analysis was conducted to assess the flexural performance, permeability, and resilience to rainstorm of NSRPC after flexural fatigue load, which was carried out to ascertain the fluctuations in strength and drainage efficiency over the anticipated service life. The experimental results of NSRPC with porosity levels of 0.28%, 0.56%, 0.84%, and 1.12% show that the reduction in rainstorm will first decrease and then increase with the increase of fatigue cycles. After 2×105 fatigue cycles, the corresponding NSRPC flexural strength was 5.9, 5.6, 5.4, and 4.5 MPa, respectively, and the ultimate displacement decreased by 20.2%, 25.1%, 28.0%, and 33.1%, respectively. After 2×105 fatigue cycles, NSRPCs still demonstrate good storm waterlogging resistance under 20-, 50-, and 100-year rainstorms. The maximum water retention dissipation rate of NSRPC can reach 0.13 mm/min , and the maximum water retention depth is less than 2.5 mm. Additionally, the permeability coefficient of NSRPC remains almost unchanged with an increase in fatigue cycles. When the permeability coefficient is greater than 4.5 mm/s , the depth of stagnant water remains almost constant with the increase of the permeability coefficient. The research in this project provides a new material and direction for the study of pervious concrete to control rainstorms and waterlogging. [ABSTRACT FROM AUTHOR]

To explore the influences of different coarse aggregate replacement ratios on the high-temperature performance of recycled concrete with manufactured sand (RCM), RCM specimens were prepared with varying coarse aggregate replacement ratios (0%, 20%, 40%, 60%, 80%, 100%, mass fraction). The surface morphology, mass loss rate, compressive strength, load-deformation curve, and microscopic morphology of RCM were investigated after exposure to high temperatures. Results indicate that the RCM performs well in high-temperature tests below 600 °C when the coarse aggregate replacement ratio is between 40% and 60%. At 200 °C, the specimens in each group show minimal morphological changes, small mass loss rate, and a slight increase in compressive strength. At 400 °C, cracks begin to appear on the surface of the specimens, with mass loss rate ranging from 4. 35% to 6. 47%, and compressive strength starts to decline. At this point, the coarse aggregate replacement ratio has a minor impact. At 600 °C, significant changes in surface morphology are observed, with mass loss rate increasing to 6. 42% ~ 8.70%, and compressive strength eventually decreasing to around 80% of the baseline strength. Specimens with coarse aggregate replacement ratio of 40% ~ 60% perform well under these conditions. At 800 °C, the surface morphology of specimens in all groups intensifies further. The impact becomes particularly pronounced for coarse aggregate replacement ratio exceeding 60%. Simultaneously, various performance parameters indicate that the concrete has experienced a complete loss of effectiveness at this temperature. [ABSTRACT FROM AUTHOR]

The use of recycled aggregate obtained from the crushing of construction solid waste can not only save natural sand and gravel resources, but also promote the recycling of construction solid waste. The quality of recycled aggregate determines the performance of recycled aggregate concrete. There are many factors affecting the quality of recycled aggregate, and the strength of parent concrete is one of the important influencing factors. The article takes strength of parent concrete as the research object, and summarizes its influence law on the properties of recycled aggregate and recycled aggregate concrete. Different strengths of parent concrete affect the quality and content of recycled aggregate adhesive mortar, which in turn affects the properties of recycled aggregate and recycled aggregate concrete. When the strength of parent concrete increases, the quality and content of adhesive mortar are improved. While the quality of adhesive mortar is improved, the properties of recycled aggregate and recycled aggregate concrete are strengthened. The increase in the content of adhesive mortar deteriorates the physical properties of recycled aggregate, increases the porosity and water absorption of recycled aggregate, but strengthens the internal curing effect of concrete, which contributes to the mechanical properties of recycled aggregate concrete. Using microscopic analysis, it is found that different strength of parent concrete make a difference in the content of hydration products in the interfacial transition zone of recycled aggregate concrete, which has an impact on the mechanical properties of concrete. The article provides a theoretical basis for further grading and utilization of recycled aggregate. [ABSTRACT FROM AUTHOR]