Investigation of epoxy grouts incorporating date palm waste: Mechanical performance analysis

Epoxy grouts, consisting of epoxy resins, hardeners, and fillers, are extensively used in under-grouting due to their excellent mechanical attributes. Waste material incorporation into grout composites is becoming more popular because of growing environmental consciousness and a greater focus on sustainability. Recent research focuses on integrating date palm waste into epoxy grout composites for compression-based applications, such as under-grouting. Additionally, there is a notable gap in the literature regarding the scaling-up process from laboratory experimentation to industrial-scale manufacturing of such grout composites. The present study aims to investigate the feasibility of using date palm midrib wastes for under-grouting heavy machinery and equipment in local industries within Saudi Arabia. Three kinds of epoxy grouts of the exact composition of resin and hardener but with different substitutions of silica sand with date palm midrib waste were made. The microstructure and mechanical properties of the synthesized epoxy grout composites containing varying percentages (2%, 5%, and 10%) of date palm waste, specifically comprising midribs and midrib fibres, are critically assessed. The results show that using midrib fibers resulted in lower mechanical performance of the grout composite than when date palm midribs were used. Moreover, as the amount of date palm waste increases, the mechanical performance of grout specimens decreases. At a 28-day curing time, adding up to 10% date palm waste led to a loss in compressive strength of up to 5% and 66% for the composite containing midribs and midrib fibers, respectively. Correspondingly, adding up to 10% date palm waste reduced flexural strength by 32% and 68% for composite containing midribs and midrib fibers, respectively. Scanning electron microscopy shows that the decline in the mechanical properties of the epoxy composite containing the midrib fibers is attributed to the presence of augmented voids within the microstructure of the specimens. Optical microscopy of epoxy date palm (EDP) specimens shows that the presence of date palm content results in crack propagation along midrib boundaries and through midribs during compressive loading. Except for the grout composite containing 10% midrib fiber, the synthesized epoxy grout composites incorporating date palm midrib waste are more durable and sustainable than the benchmark grout material specified for foundation and heavy machinery applications. The absence of chemical treatments and specialized facilities simplifies the scalability of grout specimen preparation from laboratory to industrial scale.