Strength analysis of nano-silica modified pervious concrete: A promising cement-based composite – Experimental and numerical investigation

This study presents a combined experimental and numerical investigation of the mechanical behaviour of nano-silica modified pervious concrete (PC), which can be considered a cement-based composite material due to its heterogeneous, multi-phase nature. A comprehensive experimental campaign evaluates nano-silica modified pervious concrete by measuring infiltration rate, density, porosity, and compressive, splitting tensile, and four-point bending strengths versus plain PC. The results indicates that nano-silica significantly reduced the infiltration rate (by approximately 40%) due to a densification of the surface layer. However, no statistically significant differences are observed between plain PC and nano-silica modified PC in terms of density, porosity, and mechanical strengths (compressive, tensile, and flexural). Advanced numerical simulations are carried out using the Lattice Discrete Element Method (LDEM), in which the composite material is represented as a 3D lattice of truss elements. A key novelty of this study is the application of a trilinear constitutive law − used for the first time − to simulate the mechanical behaviour of PC. Material heterogeneity is incorporated via a Weibull-distributed random field for fracture energy. The model accurately reproduces experimental results under compression, splitting tensile, and flexural loading, with prediction errors below 6% and crack paths matching observations.