Study on mesostructure and stress–strain characteristics of pervious concrete with different aggregate sizes

This work aimed to study the mesostructure and compressive behavior of pervious concrete (PC) with different aggregate sizes, and to explore the mechanism responsible for the resulted performance. The mesostructure of PC was quantitatively evaluated, including the distribution of internal voids, the distribution of aggregates and the thickness of cement paste using image processing technology. In addition, the full stress–strain curve of PC was obtained by the uniaxial compressive strength test, in which the uniaxial stress–strain characteristics and the whole process of compressive failure was assessed. The results show that the larger the particle size of the aggregate, the fewer the number of voids, and the larger the average diameter of voids. The aggregate distribution in PC with different aggregate sizes is different, but is approximately uniformly distributed. The cement paste thickness of the PC studied in this paper ranges from 0.4 to 0.7 mm. With the same cement content and different aggregate composition, the thickness of cement paste gradually decreases with the decrease of aggregate size. It is found that the stress–strain curve of PC has the same change trend as that of ordinary concrete, and it is a biased unimodal curve. Furthermore, the failure of the PC is proved to be a shear failure. During the destruction of PC, the aggregate is also destroyed which is different from the damage of ordinary concrete.