Evaluation of fracture energy and durability properties of pavement concrete incorporating blends of durable and non-durable limestone Aggregates: RSM modelling and optimization

Cement concrete pavements are the ground structures constructed with quasi -brittle materials which fail under fracture modes caused by traffic loading and environmental conditions. Practically, incorporating local aggregate resources is inevitable for the sustainable use of materials in construction. In this research study, a total of 15 concrete mixes with similar gradations, slump and air -content were fabricated at different substitution ratios of coarse (RC) and fine (RF) durable and non -durable aggregates. Compressive fracture energy (Gf(c)) compressive strength (fc), flexural strength (ff), and elastic modulus (E) of concrete specimens were measured. Edge -notched prism bend (ENPB) specimens were also used to determine the fracture energy under pure modes (Gf(I), Gf(II), Gf (III)). Additionally, the durability factor (Df) and weight loss (WL) of prismatic specimens after freeze-thaw exposure were measured as the common tests for evaluating the pavement concrete. These experimental data were then adapted to give predictive models in terms of RC & RF using the response surface method (RSM). Strong correlations were found between durability parameters, Gf(I) and Gf(II). Using the prediction models, the optimum substitutions were estimated at the minimum required mechanical and durability specifications. Furthermore, the higher Gf(I) and Gf(c) were found to be required for attaining sustainable design to enhance the concrete ductility under expansive stresses induced by frost action.