Structural behaviour of reinforced concrete beams containing crumb rubber and steel fibres

Abstract

This paper presents experimental work to investigate the strength and cracking characteristics of optimised self-consolidating and vibrated rubberised concrete mixtures with/without steel fibres (SFs) using large-scale reinforced concrete beams. The test beams were cast with varying percentages of crumb rubber (CR) (0 to 35%), SF volume fractions (0, 0·35 and 1%) and SF lengths (35 and 60 mm). The performance of some design codes and published empirical equations was evaluated in predicting the shear capacity and first cracking moment of the tested beams. The results showed that the inclusion of SFs could alleviate the reduction in the shear capacity and first cracking moment that resulted from the addition of CR. In addition, combining CR and SFs contributed to developing sustainable concrete beams with high deformability, reduced self-weight and improved shear capacity. The composite effect of CR and SFs also helped to narrow the developed cracks and change the failure mode from brittle shear failure into ductile flexural failure, particularly for the SF volume of 1% (35 mm length). Comparisons of the predicted and experimental results indicate that most of the proposed equations can satisfactorily estimate the shear strength, but overestimate the first cracking moment.

Analysis and Prediction of Compressive Properties for Steel Fiber‐and‐Nanosilica‐Reinforced Crumb Rubber Concrete

“…As a new type of reinforced material of concrete, steel fiber has excellent mechanical properties. Considerable studies have shown that adding steel fibers into concrete can improve the mechanical performance of concrete structural components, by delaying the development of microcracks into macrocracks, hindering the development of macrocracks and leading to stress redistribution [13][14][15][16][17][18][19][20]. Li and Li [21] studied the effects of 0.9% steel fiber volume fraction and 5% rubber particle content on the mechanical properties of high-strength concrete, including flexure, compression, and seismic behavior.…”

A Comparative Study on the Flexural Behaviour of Rubberized and Hybrid Rubberized Reinforced Concrete Beams

“…In this study, the ductility index (μ) was used to assess the influence of crumb rubber on the deformability of all the tested beams. Generally, the inclusion of the crumb rubber in beams can contribute to improving strain and deformability and enhancing the duality in terms of increase [6,29]. For instance, increasing the rubber from 0-15 % in the rubberized and hybrid rubberized concrete beams, which increased the ductility by 110.…”

“…The crack propagation and its spacing for the rubberized and hybrid rubberized concrete of tested beams were measured. According to previous studies [6,21,29,30], when the crumb rubber was added to conventional concrete, it caused more cracks. This indicates that the spacing between the two cracks will become lower whether for maximum or minimum spacing.…”

Exploring engineering properties of waste tire rubber for construction applications - a review of recent advances

“…The particles of CR treated by different methods and materials, such as H 2 SO 4 [47], NaOH [38,80,81], Ca(OH) 2 [47], KMnO 4 [82], CH 3 COOH [47], silane coupling agent (SCA) [32], ethanol [77] limestone powder and treatment [83], methanol [77], silica fume (SF) [84], cement [84], pre-coated fibers [37,69,85,86], metakaolin (MK) [35], ground granulated blast furnace slag (GGBS) [35], sand powder (SP) [57], glass powder (GP) [57], natural zeolite [38], and nano silica (NS) [40]. However, the use of steel fibers in the CR concrete results to enhanced flexural strength and splitting tensile strength, but it did not improve the compressive strength and modulus of elasticity properties [87,88].…”