Many research works have been conducted to study the fresh and hardened properties of concrete containing crumb rubber as replacement to fine aggregate. The outcome of these researches indicated that though the compressive and flexural strength of crumb rubber concrete (CRC) decreased as percentage of fine aggregate replacement increased; the CRC has lower unit weight, better slump values, better toughness and absorb more energy before failure. In view of the fact that the main strength of composite floor slab lies within the bond between the concrete and the profiled steel sheeting, therefore the using of more ductile concrete such as CRC to toping the profiled steel sheeting could produce a new composite slab system. Two sets of slabs; each set comprising three CRC composite slabs and one conventional concrete slab has been tested with two shear span (450 and 900 mm). The results showed that the CRC slabs behavior could be characterized as ductile, while the m–k value has been found to be 80.7 and 0.037, respectively.
Waste tires caused a serious disposal problem and continue to accumulate at increasing rates. If not managed properly, the waste tires will present increasing environmental problems. Therefore, exploitation of the crumb rubber from this scrap tires as sustainable building materials in the construction industry helps preserve the natural resources and also helps maintain the ecological balance. Many researches has been conducted to determine the properties of fresh and hardened concrete containing crumb rubber (rubbercrete), where the main properties of the rubbercrete which have been reported are as following:
1.
Due to the low specific gravity of crumb rubber particles; the unit weight of the rubbercrete decreases as the percentage of crumb rubber replacement increases [1], [2], [3], [4] and [5].
2.
The non polarity of crumb rubber causes water to be repelled and the air to consequently be trapped on the surface; the air content in the rubbercrete increases as the rubber content increases [1], [6] and [7].
3.
The slump value of conventional concrete can be improved by replacing part of the fine aggregate with crumb rubber [1], [2], [8], [9], [10] and [11].
4.
The compressive and flexural strength decrease as crumb rubber content increases [1], [8], [12], [13], [14], [15], [16], [17] and [18].
5.
Since the modulus elasticity (ME) of concrete depends on the modulus elasticity of the aggregates and their volumetric proportion in the matrix; the ME of rubbercrete decreases as the crumb rubber content increases [11], [19] and [20].
6.
Rubbercrete does not exhibit brittle failure under compression or splitting tensiles. Where the rubbercrete exhibits high capacity for absorbing plastic energy under both compression and tension loading. Also the rubbercrete posses’ higher toughness, where most of the total energy generated is plastic [11], [13], [16], [21], [22], [23], [24] and [25].
7.
The rubbercrete still can be used in the mild environment, whereas the additional of rubber to concrete will not dramatically affect the durability of concrete [26] and [27].
Composite slabs consist of profiled steel sheeting and in situ reinforced concrete topping. Advantages and disadvantages of using composite concrete slabs have been reported by other researchers [28], [29], [30], [31] and [32]. The shear bond between the profiled steel sheeting and concrete is difficult to predict theoretically since it is dependent upon several inter-related parameters including the geometry and flexibility of the profiled steel sheet itself. Given that the profiled steel sheeting is a ductile material and the conventional concrete is a brittle material. Therefore, the using of lighter in weight and more ductile material such as rubbercrete could yield better composite action between the profiled steel sheeting and the rubbercrete.
The following conclusions can be drawn from this paper:
1.
The ultimate failure loads of rubbercrete slabs with shorter shear span were almost similar to the conventional slab, whereas for longer shear span the conventional slab was yielded higher failure load.
2.
The conventional concrete slab failed before the concrete developed its full strain capacity (0.003–0.0035), while the CRC has developed a higher strain reading before failure.
3.
Although the profiled steel sheeting of the rubbercrete attained higher strains than the conventional concrete, it was yielded at lower load compared to the conventional concrete slab.
4.
All rubbercrete composite slabs had achieved the ductility requirements of the Eurocode 4, while the conventional concrete slabs were considered as brittle composite slabs.
5.
Rubbercrete slabs had lower initial linear (elastic) deflection phase compare to conventional concrete slabs.
6.
The m–k value of RCR composite slabs has been determined, where the m value is 80.7 N/mm2 and k value is 0.037 N/mm2.
7.
The bond shear capacity obtained by m–k method was slightly higher compared to the value obtained by the alternative method of the Eurocode4.
