Properties of concrete containing scrap-tire rubber – an overview

Disposal of waste tire rubber has become a major environmental issue in all parts of the world. Every year millions of tires are discarded, thrown away or buried all over the world, representing a very serious threat to the ecology. It was estimated that almost 1000 million tires end their service life every year and out of that, more than 50% are discarded to landfills or garbage without any treatment. By the year 2030, there would be 5000 million tires to be discarded on a regular basis. Tire burning, which was the easiest and cheapest method of disposal, causes serious fire hazards. Temperature in that area rises and the poisonous smoke with uncontrolled emissions of potentially harmful compounds is very dangerous to humans, animals and plants. The residue powder left after burning pollutes the soil. One of the possible solutions for the use of waste tire rubber is to incorporate into cement concrete. This paper presents an overview of some of the research published regarding the fresh and hardened properties of rubberized concrete. Studies show that there is a promising future for the use of waste tire rubber as a partial substitute for aggregate in cement concrete. It was noticed from literatures that workable concrete mixtures can be made with scrap tire rubber and it is possible to make light weight rubber aggregate concrete for some special purposes. Rubberized concrete shows high resistance to freeze-thaw, acid attack and chloride ion penetration. Use of silica fume in rubberized concrete enables to achieve high strength and high resistance to sulfate, acid and chloride environments.

Disposal of waste tire rubber has become one of the major environmental issues in the world. Every year millions of tires are discarded, thrown away or buried all over the world, representing a very serious threat to the ecology. It was estimated that, almost 1000 million tires end their service life every year and more than 50% are discarded without any treatment. One of the possible solutions for the use of waste tire rubber is to incorporate into cement concrete, to replace some of the natural aggregates. This paper presents the results of an experimental research to analyse the suitability of waste tire rubber as a partial substitute for natural fine aggregates in cement concrete. For the first time, three sizes of crumb rubber were mixed in definite percentages and replaced for fine aggregates from 0% to 20% in multiples of 2.5%. Tests were done to determine the mechanical properties, water absorption, resistance to sulphate attack, carbonation and porosity of these concrete samples. It was observed that the values of compressive strength, flexural tensile strength, pull-off strength and sulphate attack of rubberized concrete were lower than that of control mix; but up to a certain percentage, they gave better resistance to water absorption, and carbonation. It was concluded that there is a promising future for the use of discarded tire rubber as a partial substitute for fine aggregates in concrete, which can result in huge environmental and sustainability benefits.

Materials

Utilizing scrap tire rubber by incorporating it into concrete is a valuable option. Many researchers are interested in using rubber tire waste in concrete. The possible uses of rubber tires in concrete, however, are dispersed and unclear. Therefore, a compressive analysis is necessary to identify the benefits and drawbacks of rubber tires for concrete performance. For examination, the important areas of concrete freshness, durability, and strength properties were considered. Additionally, several treatments and a microstructure investigation were included. Although it has much promise, there are certain obstacles that prevent it from being used as an aggregate in large numbers, such as the rubber’s weak structural strength and poor binding performance with the cement matrix. Rubber, however, exhibits mechanical strength comparable to reference concrete up to 20%. The evaluation also emphasizes the need for new research to advance rubberized concrete for future generations.

Solid waste management is one of the major environmental concerns all over the world and in Kuwait. Over 5 billion tons of non-hazardous solid waste materials are generated in Kuwait each year. Of these, more than 2 million scrap-tires (approximately 2 million tons) are generated each year. In addition to this, about seven million scrap-tires have been stockpiled. Due to the increasingly serious environmental problems presented by waste tires, the feasibility of using elastic and flexible tire–rubber particles as aggregate in concrete is investigated in this study. Tire–rubber particles composed of tire chips, crumb rubber, and a combination of tire chips and crumb rubber, were used to replace mineral aggregates in concrete. These particles were used to replace 10%, 15%, 20%, and 25% of the total mineral aggregate's volume in concrete. Cylindrical shape concrete specimens 15 cm in diameter and 30 cm in height were fabricated and cured. The fresh rubberized concrete exhibited lower unit weight and acceptable workability compared to plain concrete. The results of a uniaxial compressive strain control test conducted on hardened concrete specimens indicate large reductions in the strength and tangential modulus of elasticity. A significant decrease in the brittle behavior of concrete with increasing rubber content is also demonstrated using nonlinearity indices. The maximum toughness index, indicating the post failure strength of concrete, occurs in concretes with 25% rubber content. Unlike plain concrete, the failure state in rubberized concrete occurs gently and uniformly, and does not cause any separation in the specimen. Crack width and its propagation velocity in rubberized concrete are lower than those of plain concrete. Ultrasonic analysis reveals large reductions in the ultrasonic modulus and high sound absorption for tire–rubber concrete.

Journal of Materials in Civil Engineering, 2004

Over the years, there has been mounting interest in the use of recycled tire rubbers in highway construction. Tire rubber-filled concrete, a rubberized Portland cement concrete with a portion of aggregates replaced by tire rubber particles, represents an alternative of using recycled tire rubbers. It is found that rubberized concrete has very high toughness. However, its strength decreases significantly as the rubber content increases. This limits its application to secondary structural components only. Very little progress has been made in increasing the strength of rubberized concrete due to the lack of understanding of the toughing mechanism. In this study, rubberized concrete was treated as a multiphase particulate-filled composite material. A modified three-layer built-in composite model was proposed based on a previous study on ordinary concrete. Finite element analysis was conducted on the developed composite model. Cylindrical rubberized concrete samples and ordinary concrete samples were prepared and tested to provide basic physical/mechanical properties in the analysis. The effect of various design parameters on the composite strength was evaluated. The finite element analysis validated the test results.

Advances in Applied Mechanics

The enormous quantity of vehicle nowadays, to some extent, undermined the environment. Increasing the number of cars indirectly produce high volume of waste tires. The presence of waste tires is a major factor that contributes to the risk of breeding places for mosquitoes, while burning tires will cause air pollution. To minimize this problem from becoming more serious, many alternatives have been implemented recently, such as the application of waste tire as a construction material. The main concept is to reduce air pollution and to produce concrete that is environmentally friendly and practical for the construction industry. Based on these objectives, this study was conducted to determine whether rubber tires can act as a concrete additive. Pieces of waste tire replaced the aggregate in the concrete mix design. The size of the tire rubber was in the range between 10 – 20 mm. The mixture of coarse aggregate replacement percentages of rubber tires by weight were 1%, 3 % and 5%. Conc...

Crystals

The phenomenon of dumping used tires in Kuwait has reached critical levels, with a landfill containing millions of tires being formed in a remote area, which is a major environmental hazard. Nowadays, recycled rubber is used as a suitable and useful material in civil engineering applications, particularly in the production of “green concrete”. This study aims to see whether recycled tire by-products can be used to make “green concrete” for pavements. Each type of tire by-product was tested individually to examine its properties and effects on a benchmark mix before creating hybrid mixes that contain a combination of the materials. Eleven mixes containing different doses of shredded or crumbed rubber or steel fibers contained within the tires were made to evaluate their impact on the concrete’s slump, compressive strength, split tensile strength, and modulus of rupture. Additionally, twelve hybrid concrete mixes containing different doses of various tire by-products were developed. P...

Frontiers in Materials, 2020

Studies have shown that the incorporation of waste tire rubber aggregates reduces the strength, increases permeability and decrease thermal conductivity of concrete. However, only a few studies have investigated the effect of surface-modified rubber aggregates on the properties of concrete. This study investigates the effect of the surface treatment of waste tire rubber as coarse aggregates with different oxidizing solutions and different treatment durations on the mechanical, durability and thermal properties of concrete. The properties of concrete incorporated with 8% rubber coarse aggregates (by volume of natural aggregates) which were treated with three different solutions: water (H 2 O), 20% sodium hydroxide (NaOH) and 5% calcium hypochlorite [Ca(ClO) 2 ] (both as% weight of water) for durations of 2, 24, and 72 h, respectively. The effect of these treatments on the compressive strength, splitting tensile strength, water permeability, thermal conductivity and diffusivity of concrete was investigated. Results show that Ca(ClO)2 has a more positive effect on the strength and permeability compared to NaOH solution and water. Experimental results were statistically analyzed using ANOVA and Post Hoc tests. The analyses showed that the improvement of concrete strength is only significant when the treatment with NaOH and Ca(ClO) 2 is prolonged to 72 h. Furthermore, the microstructural analysis of concrete showed that the improvement in the strength is due to the improved bonding between cement paste and rubber aggregates as a result of surface treatment. This microstructural improvement also resulted in lower water permeability of concrete. However, the thermal conductivity and diffusivity increased when the surface treatment duration increases as there are less air voids in the samples. This study shows that, with appropriate pretreatment, a certain percentage of natural aggregates can be safely replaced with waste tire rubber aggregates while maintaining sufficient quality of the resulting concrete.

Transportation Research Record, 1996

Because used tires represent an increasingly serious environmental problem in the United States, this study was undertaken to examine the feasibility of using finely ground rubber in Portland-cement concrete. Various percentages of rubber, by weight of cement, were added to a control mix and the effects on the plastic and hardened properties of concrete were investigated. Workability of the mixes was affected, but it was controllable. For hardened concretes, the tests were conducted for compressive strength, split-cylinder strength, modulus of elasticity, and flexural strength. Stress-strain response was also investigated. The strength and stiffness characteristics were markedly reduced for rubcrete mixtures.

Open Journal of Civil Engineering, 2012

This experimental work investigates the impact of substituting part of the conventional aggregates with rubber aggregates on certain characteristics of the cement concretes. This incorporation of rubber aggregates resulting from cutting worn tires in practical sizes decreases the mechanical resistances of the concretes while improving slightly the fluidity of the tested mixtures. The effect of these aggregates on the shrinkage of the concretes at an early age is appreciable and even very interesting for the concretes used, for example, in road construction. This technique of cutting worn tires without any further treatment makes it accessible to everyone which helps not only in saving the environment by getting rid of this cumbersome waste but also in saving traditional aggregates.