End-of-Life cars and trucks Tyres (ELT) are still an environmental issue around the world and in Latvia. The addition of rubber additives into concrete is quite well-studied worldwide. It is known that the introduction of rubber crumb in large quantities (> 5 % by volume) reduces the mechanical strength of the material and the modulus of elasticity. The results have shown us differences between rubber crumb practical size, and the amount of admixture in concrete. Achieved results clearly showed us the difference between shredded rubber micro granules and disintegrated-like admixture particles to achieve the composite concrete water absorption differences in 0,6 % but compress strength in greater diapason.