Assessment of the mechanical performance of crumb rubber concrete

• Published in: Construction & building materials Vol. 125; pp. 175 - 183
• Main Authors: Youssf, Osama, Mills, Julie E., Hassanli, Reza
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 30.10.2016; Elsevier B.V
• Subjects: Analysis; Cement; Cement content; Concrete; Crumb rubber; Mechanical properties; Rubber; Rubber treatment; Rubberized concrete; Silica fume; United States; Cement content; Rubberized concrete; Rubber treatment; Crumb rubber; Silica fume
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2016.08.040

•Enhancement study of CRC mechanical performance was carried out.•Effect of pre-treatment period, SF additives, and cement content was assessed.•0.5h pre-treatment, 0% SF, and 350kg/m3 cement were the best alternatives.•More than 0.5h pre-treatment did not significantly affect CRC properties.•Higher than 350kg/m3 cement did not significantly affect CRC properties. Crumb rubber concrete (CRC) has some known shortcomings in mechanical performance compared to conventional concrete, particularly with respect to compressive strength. Many previous researchers have tried to overcome the material deficiencies using different methods; however, the results have often been contradictory and highly variable. In this research, three methods to improve and then assess the mechanical performance of CRC have been examined namely, rubber pre-treatment using sodium hydroxide (NaOH) solution, using silica fume additives, and increasing concrete cement content. The effect of the rubber pre-treatment time (0–2h), silica fume content (0–15%), and cement content (300–400kg/m3) on CRC slump, short and long term compressive strength, and tensile strength were measured for fifteen concrete mixes prepared with 0% and 20% rubber content. Six 100×200mm cylinders were prepared from each mix for evaluating the compressive strength at 7 and 28days. Four additional 100×200mm cylinders were prepared from two mixes for evaluating the compressive strength at 56 and 84days. In addition, two 150×300mm cylinders for each mix were prepared and tested to determine the indirect tensile strength at 28days. The results showed that 0.5h of rubber pre-treatment using NaOH solution, 0% of silica fume replacing cement by weight, and 350kg/m3 cement content were the best alternatives in this assessment range to enhance the CRC performance.