Strength Reduction Factor of Concrete with Recycled Rubber Aggregates from Tires

Recycling of waste tire rubber is a significant environmental problem due to the huge number of waste tires needing disposal. A promising alternative to methodologies usually used for this aim is the use of tire rubber in the construction industry as artificial aggregate in concrete. This paper investigated the effects on the concrete compressive strength of the partial replacement of natural aggregates with waste tire rubber. Different types and amounts of natural aggregate substitutions were considered, with percentages of rubber ranging from 0% to 100% and including only fine aggregates (F), only coarse aggregates (C), and fine and coarse aggregates simultaneously (C&F). A literature review and new experimental data were considered, presenting about 1,500 tests from dozens of different authors in more than 20 independent studies, included the present one. Based on this large data set, new analytical relationships were developed and proposed to analyze the concrete strength reduction factor (SRF) expected as a consequence of natural aggregate substitution with rubber, and the relationship with the equivalent degree of compaction (EDC) of the mixture was considered.