# Method to Predict Salt Expansion Deformation in Cement-Stabilized Macadam Under Sulfate Attack Based on Pore Evolution

## TL;DR

This paper studies how salt expansion deformation in cement-stabilized macadam is influenced by its pore structure and sulfate content.

## Contribution

A new prediction model for salt expansion deformation is proposed based on pore structure and sulfate content.

## Key findings

- Ettringite and sodium sulfate decahydrate crystals are key factors in salt expansion deformation.
- Increasing sulfate content reduces porosity and increases linear expansion rate.
- The proposed model predicts deformation with less than 10% error.

## Abstract

Cement-stabilized macadam often shows salt expansion deformation under the action of a sulfate attack, and its pore structure determines its ability to accommodate this deformation. In this paper, the influence of the pore structure of cement-stabilized macadam on its macroscopic deformation is analyzed using a single-grain salt expansion deformation test, scanning electron microscopy (SEM), and computerized tomography (CT) scanning. The results show that ettringite and sodium sulfate decahydrate crystals are key factors in salt expansion deformation. In addition, we find that when the sulfate content increases from 0% to 5%, the porosity of the mixture decreases by 1.5%, the proportion of primary pores increases by 12.1%, and the linear expansion rate increases by 0.05%. Finally, a salt expansion deformation prediction model for cement-stabilized macadam is proposed, which takes the porosity of the mixture, the proportion of graded pores, and the deformation influence factor as parameters, and the error is found to be less than 10%.