# Assessment of the Mechanical Properties and Durability of Cement Mortars Modified with Polyurethane Foam Waste

## TL;DR

This study explores using polyurethane foam waste in cement mortars to create lightweight, durable, and eco-friendly construction materials.

## Contribution

The study identifies optimal waste proportions for enhancing mortar properties while supporting sustainability in construction.

## Key findings

- Adding 1% polyurethane foam waste reduces density without compromising strength and frost resistance.
- Higher waste content (2–3%) significantly weakens mechanical properties due to increased porosity.
- All samples showed increased strength after freeze–thaw cycles, likely due to continued hydration.

## Abstract

In the era of growing demand for sustainable solutions in construction, increasing attention is being paid to the potential use of waste materials as components of building composites. This article presents the results of a study on the impact of ground polyurethane foam waste on the mechanical properties and durability of cement mortars. The waste, derived from industrial production processes, was used as a partial replacement for fine aggregates in various proportions. The analysis included bulk density, compressive and flexural strengths, water absorption, and resistance to freeze–thaw cycles. The results indicate that adding waste reduces the density of the mortar, which can be advantageous in applications requiring lightweight materials. The most favourable balance of strength retention, density reduction, and frost resistance was observed with a 1% addition, as the mortar maintained good mechanical performance and freeze–thaw durability while achieving reduced weight. Higher waste content (2–3%) led to significant deterioration of the mechanical properties due to increased porosity. All samples exhibited increased strength after 25 freeze–thaw cycles, possibly due to continued hydration under moist low-temperature conditions. The analysis of the microstructure of cement coatings with the addition of polyurethane foam enabled the explanation of the causes of the observed changes in physico-mechanical properties resulting from ageing factors. This study suggests that small amounts of waste can be effectively used to produce lightweight and environmentally friendly construction materials, supporting circular economy practices.