Preparation and flexural fatigue resistance of self-compacting road concrete incorporating nano-silica particles

In this study, the mix proportion of self-compacting road concrete with ternary cementitious materials was optimized by incorporating nano-silica particles to improve its flexural fatigue performance. The filling property and compressive strength were selected as evaluating indicators to design L-9(3(3)) orthogonal test, and then four kinds of mix proportions were selected to prepare the nano-modified self-compacting concrete (SCC) according to the results of grey relational analysis and comprehensive weighting method. The four-point flexural fatigue tests were conducted to establish the probabilistic fatigue equations of nano-modified SCC based on the two-parameter Weibull distribution with survival rates of 50% and 95%, respectively. The modification mechanism was revealed with the help of scanning electron microscopy and X-ray diffraction phase analysis. The results indicate that the optimal mix proportion of self-compacting road concrete could be obtained when nano-silica accounts for 1% of the mass of cementitious materials. The specimens with 1% nano-silica particles showed the best flexural fatigue performance, with the reduction factor of flexural strength increased by 1.5%-5.0% and the sensitivity of fatigue life to the stress levels decreased by 2.1%-9.7% at survival rate of 50%. The nanoparticles provided a physical filling effect and facilitated the formation of low-density calcium silicate hydrate gel, filling the internal micro-pores to make the structure more compact. Nano-silica improved the flexural fatigue performance of self-compacting road concrete to a certain extent. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

In this study, the mix proportion of self-compacting road concrete was optimized by incorporating nano-silica particles to enhance its flexural fatigue performance. Results showed that adding 1% nano-silica to the cementitious materials led to the best flexural fatigue performance, reducing the reduction factor of flexural strength and the sensitivity of fatigue life to stress levels.