# A Review and Experimental Study on the Performance of Rubberised Concrete Under Combined Freeze–Thaw and Sulphate Attack

## TL;DR

This study examines how concrete with recycled tire rubber performs under harsh environmental conditions like freezing, thawing, and sulfate exposure.

## Contribution

The study introduces a novel approach by selectively replacing a sand fraction with tire rubber and evaluates its durability under combined freeze–thaw and sulfate conditions.

## Key findings

- Concrete with low rubber content (5–15%) retained most mechanical strength and showed minimal surface damage after 270 days of exposure.
- Higher rubber content (≥30%) led to significant strength loss and surface degradation under the same conditions.
- Selective sand replacement resulted in slower deterioration compared to total fine aggregate substitution.

## Abstract

The use of end-of-life tyre (ELT) rubber as a partial aggregate replacement in concrete represents a promising route for waste valorisation; however, its durability-related behaviour and long-term performance remain insufficiently characterised, particularly under combined environmental exposures. This study addresses these limitations by combining a targeted literature review encompassing more than 4500 data points from over 150 published studies with a laboratory-based experimental assessment of rubberised concretes aimed at clarifying key knowledge gaps. The experimental programme investigates concretes incorporating 5–50% ELT rubber (0/4 mm) as a selective replacement of a specific sand fraction, rather than of the total fine aggregate content, with particular emphasis on performance under coupled freeze–thaw cycling and sulphate attack. A reference mix (>50 MPa at 28 days) and seven rubberised concretes were characterised in terms of mechanical behaviour and selected durability-related indicators. Specimens were subsequently exposed for 270 days to freeze–thaw cycles (−20/+20 °C) in a 10% MgSO4 solution, and surface damage and compressive strength loss were quantified. Increasing rubber content resulted in the expected reductions in mechanical performance, accompanied by lower electrical resistivity and increased porosity and carbonation depth. However, the selective replacement of a single sand fraction led to more gradual deterioration than typically reported for global sand substitution. Under combined freeze–thaw and sulphate exposure, concretes with low rubber contents (5–15%) exhibited no observable surface damage and retained most of their mechanical capacity, with compressive strength losses below 8%, whereas mixtures with ≥30% replacement showed pronounced surface degradation and strength losses exceeding 50%.