# The Influence of Fibre and Fly Ash Additions on the Properties of Self-Compacting Concrete

## TL;DR

This study explores how adding different fibres and fly ash affects the properties of self-compacting concrete, finding that each fibre type improves specific performance characteristics.

## Contribution

The novelty lies in evaluating the specific performance improvements of steel, glass, and polypropylene fibres in self-compacting concrete for various structural applications.

## Key findings

- Glass fibres improve compressive and flexural strength by 1.6% and 29.2%, respectively.
- Polypropylene fibres reduce water absorption by 7.3%, suitable for high humidity environments.
- Steel fibres are effective in SCC for industrial flooring and dynamic load applications.

## Abstract

Self-compacting concrete (SCC) is an innovative building material that is distinguished by its ability to flow and fill forms without the need for mechanical vibration. The aim of this research was to determine the effect of different types of fibres—steel, glass, and polypropylene—on the properties of both the fresh mix (consistency, density, air content, and viscosity) and the hardened concrete (compressive strength, tensile strength in bending, density, water absorption, and frost resistance). Attention was also paid to CO2 emissions associated with cement production and the potential of their reduction by using alternative materials. The results of the conducted research demonstrate that, in terms of enhancing the mechanical properties of self-compacting concrete (SCC), the incorporation of glass fibres (GFs) leads to the most significant improvements in compressive and flexural strength—by 1.6% and 29.2%, respectively. Therefore, these fibres can be recommended for use in high-performance structural applications, such as precast elements, load-bearing components, and structures subjected to dynamic loading. Polypropylene fibres (PPFs), owing to their ability to reduce water absorption by 7.3%, may be suitable for elements exposed to high humidity and shrinkage risk, such as tunnels, fire-resistant barriers, or insulating layers. Steel fibres (SFs), in turn, have proven particularly effective in SCC used for industrial flooring and other elements exposed to cyclic dynamic loads.