Influence of aggregates, glass fibre reinforcement and recycled aggregates on polyester mortar

Abstract

As the performances of unsaturated polyester mortar are related to its composition, this research is focused on the influence of the grain size distribution of the aggregates, glass fibres reinforcement and the use of recycled aggregates on its mechanical and physical properties and microstructure. It revealed that a higher fraction of coarse sand caused a decrease in compressive (2 to 3%), tensile splitting (10 till 14%) and flexural tensile (5 to 9%) strength since the interlocking effects decrease, while microstructure analysis reveals more cracks and air voids when the filler fraction is substituted. Moreover, the addition of a small amount of glass fibres, i.e. 0.20 vol%, resulted in a decrease of 0.9, 3.4 and 4.6%, respectively, in compressive, tensile splitting and flexural tensile strength, whereas the impact toughness doubled. The properties related to the microstructure indicate that this mixture is less compacted compared to a mixture without fibre reinforcement, although the ultrasonic pulse velocity increased with 2.5%. Furthermore, the study highlights the potential of recycled polymer mortar as aggregates since enhanced tensile (18.5 and 3.9% respectively, for tensile splitting and flexural tensile strength) and impact properties (an improvement of 41.8%) were observed, while the additional tests indicate that the mixture with recycled aggregates has a less dense structure compared to the reference mixture.