Powdered vulcanized rubber waste generated in a factory was examined as a compounding additive in natural rubber compounds and in blends of natural rubber and styrene-butadiene rubber. The cure characteristics were evaluated with the Monsanto Oscillating Disc Rheometer while tensile sheets were prepared and stress-strain measurements in simple extension were used to characterize the mechanical properties of the vulcanized elastomers. In all the vulcanizates examined, the incorporation of rubber waste resulted in a slight deterioration of properties. The deterioration of properties is attributed tQ the poor interfacial bonding between the rubber waste and the virgin matrix elastomer. Also, it was found that at low volume loading, the vulcanized waste has no adverse effect on vulcanizate properties.

The behavior of concrete subjected to impact load, is different compared to the behavior under static loading. A test program was carried out to determine static and dynamic properties of rubberized concrete. In this study, waste tire rubber particles were replaced with fine aggregate in concrete mixture in 3 sizes, 0-1, 1-3 and 3-5 mm and in volume ratio of 0%, 10%, 20%, 30%, 40% and 50%. Static and dynamic tests are done with hydraulic and drop hammer machines. Results of compressive and flexural strength, velocity of ultrasonic wave, Static and dynamic modulus of elasticity, strain and Static and absorption energy of rubberized concrete are determined. The results indicated that: larger rubber particles in replacement of sand have better results than smaller sizes. Also increased in rubber content, decreased the unit weight, compressive strength and static and dynamic modulus of elasticity of rubberized concrete. Using rubber particles in concrete significantly increased the ductility and strain capacity of concrete. In addition in this study equation of impact test with using mass-spring modelling, was determined.

The waste tyres represent a source of energy and valuable hydrocarbon products. Waste tyres were pyrolysed catalytically in a batch reactor under atmospheric pressure. The effects of basic catalysts (MgO and CaCO3) were studied on the pyrolysis products. The distribution ratio of gas, liquid and char with MgO and CaCO3 were 24.4:39.8:35.8 wt % and 32.5:32.2:35.2 wt % respectively at 350oC for 2hr catalytic pyrolysis. The physical and chemical properties of the pyrolzed products obtained were characterized. Both catalysts produced 25% wt of aliphatic hydrocarbons but with the use of magnesium oxide the aromatic hydrocarbons increased (55%) and polar hydrocarbons (20%) decreased as compared to calcium carbonate catalyst (50% aromatic and 25% polar hydrocarbons). As far as the distillation data and fuel tests are concerned, the oil fractions with both catalysts fulfill the present specifications of diesel fuel commercial products.

In the present study, the effects of waste calcium carbonate on properties of rubber were investigated. The rubber samples were prepared with weight percentage 15Wt% of waste calcium carbonate (four different samples), pressed in 4-MPa and sintered at 1500C for 60 minutes. The properties such as hardness, elongation at rupture, tensile strength and 300% modulus were measured. The chemical analysis of calcium carbonate was investigated through X-Ray Fluorescence method (XRF) and sizing distribution of calcium carbonate were carried out through Laser Particle Size Analyzer device (LPSA). The results indicated that by increasing the waste calcium carbonate weight percentage up to 15Wt%, the physical properties of the rubbers improved. Also, more increasing the waste calcium carbonate led to decrease in favorable properties and standard.

Dissemination of polymeric waste in the environment is one of the most important concerns of the world today. Used plastics and worn tires are one of the most important sources of this type of waste. Chemically, these materials are very similar to bitumen as the most used and expensive component of asphalt mixtures. Therefore, using these waste materials as an additive in bitumen while reducing environmental pollution can improve the performance characteristics of the pavement. Investigating the effect of each type of additive on the fatigue performance of asphalt mixture is essential as one of the most important factors in causing pavement damage. Therefore, in this research, in addition to examining the physical properties of bitumen, the fatigue performance of asphalt mixture containing different percentages of waste plastic and rubber powder has been investigated using the four-point bending beam method. The results of this test using the hardness method, Normalized hardness and energy method were analyzed. The results showed that waste plastic reduced the fatigue resistance of the asphalt mixture, which was compensated to a significant extent by adding rubber powder. So that the samples containing rubber powder and waste plastic at the same time had a longer fatigue life than the control sample.

Background and Objective: The significant growth in global vehicle usage has introduced various environmental challenges, particularly the management of waste tires. Due to their long decomposition time and the environmental hazards associated with their accumulation, waste tires pose a severe threat to ecosystems. A sustainable approach to mitigating these adverse effects involves the partial replacement of fine and coarse aggregates in concrete with waste tires. However, existing research on the impact of waste tire utilization on the mechanical properties of concrete remains limited, and global trends in this field have not been sufficiently analyzed. This study aims to evaluate the potential of waste tires for improving the mechanical properties of concrete and to analyze global trends in this innovative approach. Materials and Methods: To assess the effects of crumb and powdered tires on the compressive strength and workability of concrete, the Taguchi experimental design method and analysis of variance (ANOVA) were employed. Additionally, data from the Scopus database were analyzed using VOSviewer software to evaluate research trends and scientific collaborations related to waste tire utilization in concrete. Results: Using optimal ratios of crumb and powdered tires enables the production of concrete with suitable compressive strength. The coefficients of determination (R²) for the 7-day compressive strength, 28-day compressive strength, and workability were 92.41%, 97.82%, and 80.07%, respectively. Bibliometric analysis revealed that China and India are leading countries in publishing scientific articles in this field, reflecting a strong research focus on the use of waste tires in concrete. Conclusion: This study demonstrates that incorporating waste tires into concrete can be an effective approach to enhancing its mechanical properties. However, developing innovative technologies to optimize mixtures and improve the long-term durability of concrete remains crucial. Moreover, the bibliometric results highlight the importance of fostering greater international and multidisciplinary research in this area. Such efforts can contribute to advancing sustainable technologies in the construction industry.

There are about 152 stone sawing factory units in the Neyriz area, all sawing Neyriz marble stones. Each unit produces daily approximately 10 tons of stone powder (calcium carbonate) waste. In this research, calcium carbonate powder waste) as a filler) with other in Iran produced raw materials have been used for the manufacturing of rubber. XRF (X-Ray Fluorescence) method is used for the chemical analysis of powder waste, while PSA (Particle Size Analyzer) device, and DLS (Dynamic Light Scattering) method helped sizing recognition of the materials. Suitable formulations were considered according to the chemical composition of raw materials. Then, raw materials were mixed and uniaxially pressed, rubber samples fired at different temperatures, and the most important physical and mechanical properties such as hardness, tensile strength, elongation at rupture and 300% modulus measured. The results showed that the properties of the rubber samples made of the waste calcium carbonate powders and the rubber made in the Dena Tire Manufacturing Company are almost similar. Therefore, this powder waste with average sizing 0.533 to 1.925mm, the average of surface area and longitude equivalent diameter, respectively 0.668­ mm and 1.424mm, mean purity of 98.8%, moisture of 0.14% and correlation with calcium carbonate standard in rubber industry, can be easily used as a cheap and proper filler in the manufacturing of rubber and rubbery products.