# Effective Mechanical Properties of a Composite Material Reinforced by Oil Shale Ash Particles
### Experimental Investigations  
In a study by [PERSON], [PERSON] [14], a mixture of fly ash and epoxy resin was studied. Specimens were tested using tension and compression. The range of the filler varied from 5% to 15% by weight with a 5% step. The compression strength of the composite increased to 10% and then slightly decreased. The tensile strength also increased with the increase in the fly ash concentration. [PERSON], [PERSON] and [PERSON] [15] examined fly ash epoxy composites' tensile properties. The range of filler was 0%, 5%, 10%, 15%, 20%, 25%, and 30% by weight. The compression strength values fluctuated and peaked at 10%. The tensile modulus values peaked at 15%. No significant correlation was found between the amount of fly ash and the compression strength or tensile modulus. [PERSON], [PERSON], [PERSON], and [PERSON], [PERSON] et al. [16] investigated samples with epoxy resin in two sets: fly ash with a particle size under 53 \(\upmu\)m or a particle size under 90 \(\upmu\)m. The samples were tested using tension and compression. The amounts of fly ash were 10%, 30%, and 50% by volume. The tensile and compressive elastic moduli increased with the increase in the fly ash concentration in the composite material without dependence on the size of the particles. The tensile strength increased, increasing to 30% by volume of fly ash, and then it decreased for both 53 \(\upmu\)m and 90 \(\upmu\)m, similarly to the compressive strength. In a study by [PERSON], [PERSON] et al. [17], epoxy and fly ash composites were investigated. Tensile and compressive tests were performed. The tensile and compressive strength increased with the increase in the amount of fly ash. The amounts of fly ash were 0%, 5%, 10%, 15%, and 20% by weight. Fly ash, used in conjunction with bis(triethoxysilypropyl)tetrasulphane (TESPT) as a coupling agent, has been investigated as a reinforcing filler for polyisoprene compounds in [18].  
In a study by [PERSON], [PERSON] [19], concrete specimens in which the cement was partially replaced by fly ash were fabricated and subjected to compressive tests. Samples in which cement was replaced by fly ash at 0%, 30%, 40%, and 50% by weight were produced and tested after 28 days of aging. The compressive elastic modulus decreased with the increase in fly ash in the concrete mixtures. In a study by [PERSON], [PERSON] et al. [20], samples with 0%, 30%, 40%, and 50% fly ash content replacing cement in concrete mixtures were tested. Samples that were aged for 28 days showed the same correlation between the amount of fly ash by weight and the compressive modulus of elasticity as that in the study by [PERSON], [PERSON] et al. A similar correlation was found to be true for compressive strength; by increasing the concentration of the fly ash, the compressive strength decreased. In a study by [PERSON], [PERSON] et al. [21], samples with 0%, 10%, 20%, 30%, and 40% fly ash replacements by weight were produced and tested after 28 days of aging. The compressive strength decreased with an increase in the amount of fly ash in the concrete. In a study by [PERSON], [PERSON] et al. [22], the replacement of cement in concrete specimens with fly ash occurred in amounts of 15%, 30%, and 45%. The compressive strength decreased with the increase in the amount of fly ash in the concrete. In a study by [PERSON], [PERSON] et al. [23], compressive tests were conducted on concrete and fly ash specimens that were aged for 28 days. The compressive strength decreased with the increase in the amount of fly ash. The replacement of cement with fly ash occurred in amounts of 0%, 25%, 35%, and 55% by weight. This result was the reverse of that in the case of epoxy resin. Based on the results obtained in the studies mentioned above and keeping in mind that the density of OSA particle material is close to that of fly ash, we can expect to obtain composites with OSA that have mechanical properties similar to those of composites with fly ash. This will be investigated in this study.