TY - JOUR
T1 - Mechanical properties and improvement mechanism of pervious concrete made with modified recycled aggregates
AU - Yang, Jingyu
AU - Chen, Yuanzhao
AU - Chen, Guojian
AU - Wang, Decai
AU - Tam, Vivian WY
AU - Guo, Tengteng
AU - Li, Peiran
AU - Li, Zhenxia
AU - Fang, Chenze
AU - Shen, Aiqin
PY - 2025/9/5
Y1 - 2025/9/5
N2 - The use of recycled aggregate (RA) instead of natural aggregate for construction has the double role of clean production with economic and environmental benefits, but recycled aggregates need to be modified to meet the construction requirements due to their poor performance. This paper investigates the effect of RA improved by three compound methods—sodium silicate-silane (SS), pozzolan slurry (PS) and pozzolan slurry-sodium silicate-silane (PS-SS)—on the mechanical properties of pervious concrete (PC). The adhesion properties between RA and cement matrix, as well as the microstructure of interfacial transition zone (ITZ), were analyzed by CT, SEM, and microhardness measurements, combined with two- and three-dimensional processing techniques. The analyses revealed the mechanism by which these three methods improve the performance of recycled aggregate pervious concrete (RAPC). The results indicate that while RA negatively impacts both the strength and flexural toughness of PC, all three improvement methods were able to mitigate these adverse effects. The mechanical properties of the improved RAPC approached or even exceeded those of natural aggregate pervious concrete (NAC). In addition, the peak of the probability density of cement matrix thickness on the improved RA surface increased by approximately 0.5 mm, and the proportion of cement matrix in the bonding zone was improved. Moreover, the improved RA exhibited fewer cracks and lower porosity in the ITZ and adjacent weak zone due to lower water absorption and better adhesion to the cement matrix. Microhardness results also showed that the ITZ in RAPCs improved by SS, PS, and PS-SS increased by about 10 MPa, 5 MPa, and 15 MPa, respectively, compared to those in unimproved RAPCs, and their widths of the ITZs also decreased by about 30 μm, 20 μm, and 40 μm, respectively. All three methods can improve the mechanical properties of RAPCs, with the PS-SS method providing the best improvement and providing a reliable method for wider application of RAPCs and mitigation of environmental impacts of construction.
AB - The use of recycled aggregate (RA) instead of natural aggregate for construction has the double role of clean production with economic and environmental benefits, but recycled aggregates need to be modified to meet the construction requirements due to their poor performance. This paper investigates the effect of RA improved by three compound methods—sodium silicate-silane (SS), pozzolan slurry (PS) and pozzolan slurry-sodium silicate-silane (PS-SS)—on the mechanical properties of pervious concrete (PC). The adhesion properties between RA and cement matrix, as well as the microstructure of interfacial transition zone (ITZ), were analyzed by CT, SEM, and microhardness measurements, combined with two- and three-dimensional processing techniques. The analyses revealed the mechanism by which these three methods improve the performance of recycled aggregate pervious concrete (RAPC). The results indicate that while RA negatively impacts both the strength and flexural toughness of PC, all three improvement methods were able to mitigate these adverse effects. The mechanical properties of the improved RAPC approached or even exceeded those of natural aggregate pervious concrete (NAC). In addition, the peak of the probability density of cement matrix thickness on the improved RA surface increased by approximately 0.5 mm, and the proportion of cement matrix in the bonding zone was improved. Moreover, the improved RA exhibited fewer cracks and lower porosity in the ITZ and adjacent weak zone due to lower water absorption and better adhesion to the cement matrix. Microhardness results also showed that the ITZ in RAPCs improved by SS, PS, and PS-SS increased by about 10 MPa, 5 MPa, and 15 MPa, respectively, compared to those in unimproved RAPCs, and their widths of the ITZs also decreased by about 30 μm, 20 μm, and 40 μm, respectively. All three methods can improve the mechanical properties of RAPCs, with the PS-SS method providing the best improvement and providing a reliable method for wider application of RAPCs and mitigation of environmental impacts of construction.
KW - Cement matrix
KW - Interface transition zone
KW - Mechanical properties
KW - Microhardness
KW - Pore
KW - Recycled aggregate pervious concrete
UR - http://www.scopus.com/inward/record.url?scp=105009695807&partnerID=8YFLogxK
UR - https://go.openathens.net/redirector/westernsydney.edu.au?url=https://doi.org/10.1016/j.conbuildmat.2025.142548
U2 - 10.1016/j.conbuildmat.2025.142548
DO - 10.1016/j.conbuildmat.2025.142548
M3 - Article
AN - SCOPUS:105009695807
SN - 0950-0618
VL - 490
JO - Construction and Building Materials
JF - Construction and Building Materials
M1 - 142548
ER -
