Sulphate resistance prediction of RAC considering the coupling effect of RCA and water-binder ratio based on experimental analysis and LSSVM

ABSTRACT

Waste concrete removed from old pavement can be crushed and sieved as recycled aggregate to prepare concrete, and the application of recycled aggregate concrete (RAC) can reduce the occupation of land resources by the waste concrete and save natural aggregate. In this paper, the influence of proportion of recycled coarse aggregate (RCA) replacing natural coarse aggregate (NCA) and water-binder ratio on the sulphate resistance of RAC was studied, and the compressive strength degradation rate (D_f) was introduced to evaluate the sulphate resistance of RAC. The experimental results showed that the compressive strength of RAC before and after sulphate attacks linearly decreased with the growth of the replacement rate of RCA, water-binder ratio, and the number of sulphate wet-dry cycles, respectively; while D_f of RAC increased with the rise of the replacement rate of RCA, water-binder ratio, and sulphate wet-dry cycles, respectively. The results also indicated that D_f of all groups of RAC was less than 25%, which can meet the engineering requirements. In addition, the D_f model of RAC under a sulphate attack based on experimental data and that based on Least-Squares Support Vector Machine (LSSVM) was built and compared, and both models predict the sulphate resistance of RAC well. The prediction model based on LSSVM has higher prediction accuracy.

KEYWORDS:

• Recycled aggregate concrete
• Replacement rate of RCA
• Water-binder ratio
• Sulphate wet-dry cycles
• Compressive strength degradation rate
• Least-squares support vector machine

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by National Natural Science Foundation of China [grant number 52078232].