Influence of aggregate size on compressive strength of pervious concrete: Fid-Bau Portal

Influence of aggregate size on compressive strength of pervious concrete

Yu, Fan / Sun, Daquan / Wang, Jue / Hu, Minjun

Highlights • With the increase of aggregate size, the compressive strength increases first. When the aggregate size is beyond 7 mm, the compressive strength doesn’t change obviously. • Most of the cracks occur at the interface between cement slurry and aggregate. • The compressive strength is most sensitive to the irregularity of the pore structure and the value of Vt/St, and least sensitive to Aav. • With the increase of cementitious paste thickness, the compressive strength increases first and then remains relatively stable.

Abstract The aggregate size is an important factor influencing the compressive strength of pervious concrete. This work is focused on the study of the relationship among aggregate size, compressive strength, pore structure, cementitious paste thickness, and then understanding the influence of aggregate size on the compressive strength of pervious concrete. Eight groups of pervious concrete samples with almost the same porosity but different aggregate size were prepared. The 2D/3D pore characteristics and fractal dimension were extracted and analyzed based on CT images. The cementitious paste thickness was determined by a modified semi-manual hand measurement method. Test results show that the compressive strength increases rapidly with the increase of aggregate size at first, while the aggregate size is beyond 7 mm the effect of aggregate size on compressive strength is not so obvious. The compressive strength changes with aggregate size can be mainly attributed to the effect of aggregate size on pores characteristics and cementitious paste thickness. It is found that the compressive strength is most sensitive to the content of the small pores (0–1.5 mm²). The increase of the small pores content will decrease the compressive strength. With the increase of fractal dimension of the pores, the compressive strength first increases and then decreases. While the cementitious paste thickness is less than 1.15 mm, the compressive strength increases slowly with the cementitious paste thickness increases. Once the cementitious paste thickness exceeds 1.15 mm, the compressive strength remains relatively stable.