Multi-scale study on mechanical property and strength prediction of aeolian sand concrete

The aim of this work is to promote the utilization of aeolian sand for concrete production. The workability and mechanical property of aeolian sand concrete (ASC) is studied. The effect mechanisms of aeolian sand on the mechanical property of concrete are revealed from multiple scales. For the macro scale, use the pressure tester to test the compressive strength. For the mesoscopic, use the scanning electron microscope (SEM) to observe the structure of the interface transition zone (ITZ) and the nuclear magnetic resonance (NMR) to test the pore structure. Meanwhile, the distribution of chemical bonds is analyzed by the Fourier transform infrared (FT-IR) spectrometer and the microstructure of hydration products are characterized by the SEM for the microscopic. The results show that using parts of aeolian sand can improve the working and mechanical property of concrete. The physical influence mechanism is that it perfects the gradation of the aggregate and increases the density of concrete, reduces the effect of aggregate size and micro-region bleeding, improves the structure of ITZ and pores. For the chemical, it may accelerate the hydration reaction speed of cement and change the microstructure of hydration products. Finally, a strength prediction model of ASC is established based on the published and tested data, which agrees well with the tested result. (C) 2020 Elsevier Ltd. All rights reserved.