# Degradation Characteristics and Service Life Prediction of Desert Sand Concrete Under Load and Freeze–Thaw Conditions

## TL;DR

This study examines how desert sand concrete resists freeze-thaw damage under sustained loads in cold regions of China.

## Contribution

The research introduces a Weibull model to predict the service life of desert sand concrete under combined freeze-thaw and load conditions.

## Key findings

- Concrete with 0.3 and 0.5 stress levels retained 89.36% and 77.92% of their compressive strength after freeze-thaw cycles.
- Sustained loading improved pore structure and compactness, reducing freeze-thaw damage.
- Mesoscale damage mechanisms were identified using scanning electron microscopy and CT scanning.

## Abstract

Concrete structures in western China often endure severe freeze–thaw cycles under sustained loading. However, the combined effects of desert sand admixtures and long-term stress on freeze–thaw durability are insufficiently investigated. The existing research has focused on the material modification of desert sand concrete (DSC) or on the mechanical-environment coupling of ordinary concrete. This leaves a knowledge gap about how sustained compressive stress influences the macro- and mesoscale freeze–thaw behaviour of DSC. This study systematically investigated the freeze–thaw resistance of DSC under varying sustained compressive stresses. Testing methods and conditions were tailored to the climatic characteristics of China’s high-altitude cold regions. Freeze–thaw degradation was assessed using mass loss, relative dynamic modulus of elasticity, and compressive strength. Controlled loading effectively mitigated freeze damage. After cyclic freeze–thaw, the 0.3 and 0.5 stress groups retained 89.36% and 77.92% of their original compressive strength, respectively. Scanning electron microscopy, mercury porosimetry, and CT scanning revealed mesoscale damage mechanisms. Sustained loading optimized pore structure and enhanced compactness. A two-parameter Weibull probability model was then established to describe damage evolution patterns and assess the service life of desert sand concrete under regional climatic conditions.