Waste tyre-rubber disposal is a serious global problem, posing a severe danger to the environment. This present study aims to investigate the performance of concrete utilizing recycled tyre-rubber waste as a partial replacement for natural fine aggregate. Three different sizes of crumb rubber were combined to produce a well-graded sample. Based on various trials, mixed proportions of M30 grade concrete and the crumb rubber replacement percentages were determined. The test specimens were prepared. Experimental investigations have been carried out to study the mechanical, durability and temperature properties of the developed Crumb rubber concrete (CRC). In this study, crumb rubber replaced the fine aggregate in various percentages, such as (0, 5, 7.5, 10 and 15) %. Microstructural analysis was also carried out with EDX and scanning electron microscopy (SEM) to visualize the performance of rubber with CSH gel under different temperature conditions. The study found that (CRC5) a 5 % replacement of crumb rubber is the optimum percentage to replace the natural fine aggregate to develop the crumb rubber concrete. The durability tests concluded that the proposed model of rubberized concrete is suitable for any structural elements exposed to acidic environmental conditions.

Engineered cementitious composites (ECC) are special types of high-tensile and high-ductility concrete that are designed using a micromechanics approach, with a tensile strain capability of more than 3%. Due to their higher strain hardening capacity, ECC can be applied as a strengthening material on structural walls, which improves the structural strength and inelastic deformation capacity. This study presents an experimental and numerical analysis of brick masonry wall strengthened by traditional mortar, ECC, and ECC with 40% fly ash (FAECC) subjected to uniaxial compression. The tests, such as compressive strength, indirect tensile strength, and bond strength, were conducted. Based on the experimental results, a numerical model is developed, and a failure prediction for the existing masonry structure is made. The compressive strength of ECC is observed to be higher than normal mortar and FAECC whereas the indirect tensile strength of both ECC and FAECC was almost similar, which is higher than that of normal mortar. The bond strength of ECC and FAECC is found to be 70% higher than that of normal mortar. It is evident that brick masonry units strengthened by ECC have a higher compressive strength than masonry units strengthened by conventional mortar and FAECC. It also controls crack development and spalling of masonry units. Then, a micromodelling along with CDP model is made in Abaqus/CAE software and an excellent correlation between experimental and numerical results was noted. The suggested models were shown to be capable of predicting the common behaviour of masonry units.

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