The proper disposal of fibre waste products is a significant issue for the GFRP industries; as a result, the reuse and recycling of these waste products require sustainable solutions. Given that FRP materials, especially those created with thermosetting resins, cannot be reprocessed, so the majority of thermosetting FRP waste will be dumped in landfills. Innovative approaches are thus required to manage waste. This study investigates the performance of the FRP waste, known as Glass Fibre Reinforced Polymer (GFRP), that is ground to 0.15mm to 2.36mm in size and used to replace sand at 5%, 10%, 15%, 20%, and 25% by weight of the concrete composite. The experimental work starts with the grinding and sieving process, followed by preparing grade 45 concrete. Then the workability of concrete with GFRP was determined, followed by the compression, and split tensile strengths. The findings showed that adding up to 5% of GFRP waste as a partial replacement for fine aggregate improved the workability and compressive strength of the concrete mix. but decreases when more GFRP waste is added. While the split tensile strength shows increments in line with the increasing amount of GFRP waste replacement. It can be concluded that GFRP waste replacement has the potential to be used in the construction industry, however, the long-term performance must be determined first.

This paper presents the results of using ground dune sand (GDS) and ground granulated blast furnace slag (slag) as high volume cement replacement materials. In this study, plain and four blended mixtures were fabricated and cured under normal and autoclave conditions. For the blended mixtures, 40% GDS by weight of the total binder materials and different percentages of slag (15%, 30% and 45%) were incorporated as partial cement replacement materials. The effect of curing conditions (normal and autoclave) on the compressive strength of prepared mixtures was studied. The results showed that, for the autoclave cured mixture, up to 85% of cement can be replaced by GDS and slag without significant drop in the compressive strength. Microstructure analyses using scanning electron microscope (SEM) and X-ray diffraction analysis (XRD) were carried out to examine the microscale changes of the hydrated mixtures. The SEM revealed the formation of thin plate-like calcium silicate hydrate and compacted microstructure of autoclave cured mixture. XRD showed the elimination of calcium hydroxide and existence of residual crystalline silica of all blended mixtures.

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Addition or replacement of waste tyre in mortars and concretes in lightweight aggregate concrete composites are popular in concrete material research although the mechanical properties of the composite are reduced. Various research studies have been conducted in an effort to improve the mechanical properties of concretes and mortars containing waste tyre particles using chemicals and additives which lead to increase cost. This approach presents an economical and sustainable method, through adding oil palm fruit fibre (OPFF) at 0.5, 1%, and 1.5% by mass of cement content into the matrix and pre-treating the tyre crumb aggregate (0-40%) by volume with cement, in order to improve the properties of the composite. Mechanical properties including compressive strength, split tensile strength and flexural strength were measured on the mortar specimens. Results showed the addition of 0.5% OPFF in 10% treated tyre crumb mortar gives the best improvement in the mechanical strengths of mortar modified with treated tyre crumb.

Supplementary cementitious materials provide economic and environmental advantages in concrete industry. In this study, natural ground dune sand (GDS) was used as cement replacement material to fabricate mortar specimens. Ordinary Portland cement was replaced by GDS at five levels of replacement (0, 10, 20, 30, and 40 %) by weight. The cast mortar specimens were cured under normal and autoclave curing conditions. Compressive strength, drying shrinkage and resistance to sulfate attack were investigated. Results showed that the compressive strength under normal curing decreased as the level of replacement increased. However, under autoclave curing compressive strength increased as the content of GDS increased with 30% being the optimum replacement level. Autoclave curing decreased the drying shrinkage of plain and GDS blended mixtures by about 70% compared to control mixture cured under normal curing. Up to 270 days, no sulfate attack was observed on the GDS blended mixtures regardless of the replacement level. The use of GDS to reduce the Portland cement consumption can have a significant impact on the sustainability and economy of concrete construction.