Crumb Rubber Size Research Articles

Development of Crumb Rubber Concrete for Practical Application in the Residential Construction Sector – Design and Processing

Extensive research has been carried out on crumb rubber concrete (CRC) in the past 10 years due to its potential as a sustainable and environmentally friendly material. Nevertheless, the practical use of this concrete class in the concrete industry to date has been very limited. This research is a part of a project that focuses on developing CRC for practical use in residential construction. The design and processing of CRC at three grades (20 MPa, 25 MPa, and 32 MPa) was carried out and the performance was investigated and compared with conventional concrete at the same strength levels. The study included three stages namely; selecting effective rubber particle size, designing and adjusting concrete mixes, and testing recommended mixes for practical applications. The slump, compressive strength, tensile strength, flexural strength, modulus of elasticity, shrinkage, creep, rubber pre-treatment effect and mixing order effect were measured. The results showed that within the crumb rubber size range used (0.15–2.36 mm) increasing the rubber particle size decreases the compressive strength losses. Compared to conventional concrete, the presence of 20% rubber as sand volume replacement decreased the 7-day/28-day strength ratio by values that ranged between 9% and 20%. CRC exhibited similar or lower shrinkage values, but higher creep strains compared to those of conventional concrete. The rubber pre-treatment enhanced the concrete slump, but no significant effect on compressive strength was observed. When the rubber was added together with water at the beginning without being premixed, the workability was low; however, when rubber was added and mixed dry or wet with the other materials, the CRC workability was enhanced.

Mechanical properties and crack resistance of crumb rubber modified cement-stabilized macadam

With the development of the transportation industry in the past decades, the amount of waste tires annually has increased rapidly. In consideration of the successful application of rubberised concrete and recycling utilization of waste tire rubber, this study aimed to evaluate the potential effect of crumb rubber manufactured by waste tires on the mechanical properties and crack resistance of cement-stabilized macadam (CSM). Three different particle sizes of crumb rubber (40 mesh, 60 mesh, and 80 mesh) were incorporated into CSM with three different contents (substituting 1.0%, 1.5%, and 2.0% of fine aggregates by volume). Unconfined compressive strength test, splitting strength test, compressive resilient modulus test, dry shrinkage test and scanning electron microscopy (SEM) test were performed in this study. The results indicated that due to the elasticity of rubber particle, the compressive strength of CSM was decreased with the increase in rubber content. The incorporation of crumb rubber effectively reduced the resilient modulus of CSM. However, the adverse influence on the splitting strength was not obvious when a low volume of crumb rubber was incorporated. According to the results of dry shrinkage test, the incorporation of crumb rubber could significantly improve volume shrinkage resistance of CSM, thereby preventing against the formation and propagation of initial cracks. Moreover, the SEM images demonstrated that the cement hydration near rubber particles was hindered and led to the poor interfacial adhesion bond between cement mortar and crumb rubber. The small micro-cracks between cement matrix and rubber particle made space for the extension of dry shrinkage cracks, which revealed the improvement on the crack resistance of crumb rubber modified macadam.

Discrete Element Modelling of Rubber-Protected Ballast Performance Subjected to Direct Shear Test and Cyclic Loading

The rubber-protected ballast (RPB) is made from natural ballast particles and crumb rubber particles. The crumb rubber is shredded waste tires. RPB was chosen to replace the ballast as it has higher resistance to breakage and abrasion. However, the static and dynamic performance of the RPB has not been confirmed yet. Towards this end, experimental tests and numerical simulations were utilized to study the feasibility of RPB application. Direct shear tests (DSTs) were performed and a DST model and three-sleeper track model with the discrete element method (DEM) were built. The shear strength, settlement, displacement, and acceleration of the RPB were studied. The results show that the RPB has the advantage of increasing the force (stress) distribution and that the smaller crumb rubber size was more suitable for replacing the ballast particles.

Hydraulic conductivity of fresh railway ballast mixed with crumb rubber considering size and percentage of crumb rubber as well as aggregate gradation

Degradation of ballast aggregate leads to the drainage problem along with less stability of the ballasted railway track. Using crumb rubber (CR) as waste material incorporated in ballast aggregate results in attenuation of aggregate degradation as well as reduction of the noise level generated from passing trains. The size and quantity of rubber material mixed with ballast aggregate are important factors which affect the stability and hydraulic conductivity of ballast course. Therefore, the present study investigates the influence of size and percentage of CR on hydraulic conductivity of fresh ballast aggregate mixed with rubber particles. For this purpose, large-scale constant head permeability test is conducted on rubber modified ballast aggregate by taking into account the initial gradation of aggregate along with the size and amount of CR. Generally, using smaller-sized rubber particles and increasing the percentage of CR leads to further decrement of hydraulic conductivity of ballast, especially for more broadly-graded aggregate. However, the permeability level characterized by laminar and non-laminar flow regime is still acceptable. In addition, the hydraulic conductivity of ballast comprised of more uniform range of aggregate is further reduced by adding larger-sized CR particles. Furthermore, water movement through prepared specimens of rubber modified ballast obeys nonlinear relationship characterized as flow regime between laminar and turbulent.

Effects of Crumb Rubber Size and Concentration on Marshall Parameters of Rubberized Asphalt Mixture

The depletion of natural aggregate sources which generally accounts for a huge percent of Hot Mixed Asphalts (HMAs) and the difficulty posed by disposal scrap tires are a major environmental concern for the future. The use of waste products like scrap tires in highway construction is considered a sustainable way of dealing with these issues. Crumb rubber is a material pulverized from waste polymer products like scrap tires which are then added to HMAs to improve their performance. This study focuses on the sensitivity of crumb rubber particle sizes (fine ≤1.18 mm), (coarse ≥1.18 mm and ≤3.35 mm) (and mix of 50% fine and 50% coarse) and partial replacement (1.5 and 2.5% of total weight) of aggregates on the Marshall test parameters of rubberized asphalt mixes. The Marshall test parameters: density, stability, VTM, VFB of both rubberized asphalt and conventional asphalt samples were compared and also the Asphalt Institute (AI) and National Asphalt Pavement Association (NAPA) methods were used to obtain the optimum bitumen content (OBC). From the results, it suggests that; the utilization of dry process methodology of adding crumb rubber additives in different sizes and percentages had a considerable effect on Marshal test parameters and also influences the optimum binder content estimates. The results of this study can be used as a reference point for the use of crumb rubber in HMAs.

High temperature rheological characteristics of plasma-treated crumb rubber modified binders

This study investigated the effect of cold plasma surface treatment of crumb rubber on the high temperature performances of CRM binders at unaged and RTFO-aged states, which were produced with two base asphalts and three crumb rubber sizes. The high temperature performance tests conducted on the rubberized binders included rotational viscosity, failure temperature, rutting factor, phase angle, storage modulus, and loss modulus at different temperatures. According to the result of performance tests and statistical analyses, cold plasma surface treatment on crumb rubber significantly enhanced the high temperature performances of CRM binders, regardless of base asphalt source, crumb rubber size and aging state. The effect of base asphalt source was mainly reflected in determining the high temperature performances of RTFO-aged binders. With respect to the crumb rubber size, the -40 mesh plasma-treated CRM binders were the most desirable. In addition, the RTFO aging caused an enhancement in elasticity and viscosity of plasma-treated CRM binders as expected. Finally, the Gray Relational Analysis (GRA) determined the coupling effect of these variables, indicating that cold plasma surface treatment of -40 mesh crumb rubber and base asphalt A was the most effective combination in terms of high temperature rheological properties of CRM binders.

The use of crumb rubber for replacing fine aggregate in cold mixture asphalt

In order to consider the environmental impact, this study investigated the effect of crumb rubber on the mechanical performance of cold mixture asphalt. Crumb rubber was obtained from the process of recycling waste tires, which this waste material becomes a major environmental problem due to the rapid increase in the number of motor vehicles in Indonesia. Cold mixture asphalt is an environmental friendly option on flexible pavement, which reduces energy consumption because it does not need heat during the process as in hot mixture asphalt. In this study, laboratory tests were conducted for Dense Graded Emulsion Mixture Type IV. The first stage in this study was to perform laboratory experiments on compacted mixture to determine the optimum residual bitumen content. In the next stage, a series of tests on crumb rubber mixtures were conducted in the optimum residual bitumen content condition to investigate the effect of crumb rubber as a partial replacement of fine aggregate. Fine aggregate in cold mixture asphalt was replaced with 50% of crumb rubber. Three different sizes of crumb rubber, 20 mesh (0.841 mm), 40 mesh (0.42 mm) and 60 mesh (0.25 mm), were applied in a series of laboratory experiments. Tests were done using Marshall Test equipment to obtain the mechanical performance of cold mixture asphalt. The finding indicated that finer crumb rubber produced higher stability than the larger size of crumb rubber. Even though the use of crumb rubber decreased stability of mixtures, it still met the minimum specified requirement of cold mixture asphalt. The stability of the crumb rubber cold mixtures were also comparable to hot mixture asphalt. Replacement of fine aggregate with crumb rubber on cold mixture asphalt is expected to overcome the environmental problems by reuse the waste materials to preserve the natural aggregates.

Crumb Rubber Modifier in Road Asphalt Pavements: State of the Art and Statistics

Tire rubber recycling for civil engineering applications and products is developing faster, achieving increasingly higher levels of maturation. The improvements in the material circle, where crumb rubber, generated as a by-product of the tire rubber making process, becomes the resource used for the construction of road asphalt pavement, is absolutely necessary for increasing the sustainability of the entire supply chain. The paper reports the results of an accurate data analysis derived from an extensive literature review of existing processes, technologies, and materials within construction of infrastructure. The current position, the direction, and rate of progress of the scientific efforts towards the reuse and recycling of tire rubber worldwide have been shown. Furthermore, an in-depth analysis of a set of important properties of Crumb Rubber Modified Asphalt has been carried out—fabrication parameters, standard properties, high and low-temperature performance, and rheological properties. Statistics over a sample of selected publications have been presented to understand the main processes adopted, rubber particle size, temperatures, and possible further modifications of crumb rubber modified binder.

Long-term permanent deformation behaviour of recycled concrete aggregate with addition of crumb rubber in base and sub-base applications

The structural behaviour of pavements depends on the permanent and resilient deformations. These deformations are accumulated during the pavement lifetime. Although many studies have been done to explore the use of construction and demolition (C&D) waste materials in road pavement construction, the long-term permanent deformation behaviour (i.e., 100,000 loading cycles) of recycled concrete aggregate (RCA) with an addition of crumb rubber as base/subbase layers has not been studied yet. The aim of this study is to assess whether RCA combined with crumb rubber can be used as the base or sub-base materials or not. Two different crumb rubber sizes were used in this study: a fine type measuring 1–5 mm in diameter and a coarse type measuring 15–20 mm. 0.5, 1% and 2% crumb rubber by weight of the dry aggregate were added to the 20 mm RCA. A series of repeated load triaxial tests were performed to investigate the effects of the sizes and percentages of crumb rubber on the long-term permanent deformation characteristics of RCA incorporating rubber. The results show that only RCA and RCA containing 0.5% fine or coarse rubber can be used as base and sub-base material in pavement in terms of long-term permanent deformation.

Effects of crumb rubber size and percentage on degradation reduction of railway ballast

Higher speed, more freight and frequent maintenance increase ballast degradation and reduce the ballast lifespan. To reduce ballast degradation, crumb rubber used as buffering aggregates in ballast bed is relatively unexplored and needs more studies, because using it has the advantage of reusing the waster rubber and absorbing the noises. The effects of crumb rubber (CR) size and percentage on ballast degradation reduction is studied in this paper, and the optimal CR size and percentage are proposed. Three CR size ranges are utilised, i.e., 3 ∼ 5 mm, 10 ∼ 15 mm and 20 ∼ 25 mm, and the percentages are 0, 10, 20 and 30% by weight. Three kinds of ballast material with two size ranges are utilised. The deteriorated ballast particles were generated using Los Angeles Abrasion (LAA) tests, and the ballast degradation was evaluated with the 3D image analysis. The results indicate that ballast abrasion can be alleviated by adding the CR, while the CR has few influences on the ballast breakage. When CR size is close to ballast particle size, the effects of degradation reduction are not obvious. The corner and edge loss are the main types of ballast abrasion, although different ballast materials significantly influence the abrasion type and degree. Most importantly, the image analysis method is proved to have the ability to present ballast degradation process and has great potential for further degradation-related studies.

Engineering properties of crumb rubber modified dense-graded asphalt mixtures using dry process

The development and production of high quality asphalt are crucial in the effort to meet current demands for the construction of roads. Crumb rubber is an industrial waste and one of the best ways to reduce the amount of this waste is by recycling it in the asphalt industry. Crumb rubber obtained from scrap tyres has been proven to be an effective additive for the modification of the properties of asphalt mixtures. This study presents a laboratory evaluation of the properties of crumb rubber modified asphalt mixture using the dry process method by adding three different sizes of crumb rubber, namely fine (≤1.18mm), coarse (≥1.18 but ≤3.35 mm), and combination of both fine and coarse (50/50), at three different percentages of crumb rubber, 0, 1.5 and 2.5% of the total weight of the aggregate. Crumb rubber was used to modify the dense graded mixture of asphaltic concrete wearing course 14 (ACWC14). The effect of crumb rubber in the mixture was investigated in terms of the volumetric properties using the Marshall Mix Design and mixture performance testing was conducted by means of resilient modulus, dynamic creep, and abrasion loss. Results showed that fine crumb rubber improved most of the properties of asphalt mixtures compared to other types of mixtures; this could be due to the partial interaction between rubber particles and bitumen which simultaneously act as an elastic aggregate in the mixture.

Experimental investigation into the properties of self‐compacting rubberised concrete incorporating polypropylene and steel fibers

Adding a waste tyre rubber aggregate to the self‐compacting concrete forms a new type of concrete call self‐compacting rubberise concrete, which is used as a way of reducing waste and increasing sustainability in terms of the waste rubber, and changing the properties of the concrete to be more beneficial under certain circumstances and applications. In addition to adding rubber aggregates, polypropylene (PP) fibers and steel fibers are added into the concrete mix as well to create fiber reinforced self‐compacting rubberised concrete (FRSCRC). This experimental investigation is using waste tyre rubber as a replacement for the aggregate in the FRSCRC. Using crumb rubber sizes of 2–5 mm, a replacement of 20% of fine aggregates was integrated. The amount of fibers varied depending on the type of fiber. In the case of PP fibers, 0.1, 0.15, 0.2, and 0.25% by total volume were tested, and for steel, 0.25, 0.5, 0.75, and 1% were tested. These mixes were tested for their fresh properties using the slump test and the J‐ring test, and hardened properties including compressive strength, splitting tensile strength and compressive stress–strain tests. The results indicated that as more fiber is added, the larger the negative impact on the rheological properties of the FRSCRC and steel fibers having a much larger detrimental effect than PP fibers. In terms of mechanical properties, PP fibers reduced the compressive strength of the concrete as a higher percentage of fiber was added, but had no major effect on the splitting tensile strength. Steel fibers, on the other hand, showed a minor increase to compressive strength, as well as an increase to splitting tensile strength as more fibers were added.

Permanent deformation behaviour of pavement base and subbase containing recycle concrete aggregate, coarse and fine crumb rubber

Pavement layers must be sufficiently strong to carry all traffic loads and resist the accumulation of permanent deformations such as rutting and avoid premature failures including top-down cracking during their service lives. In recent years, the utilization of recycled construction and demolition (C&D) materials in civil and transportation infrastructure construction has been considered as a significant solution to replace conventional and natural aggregates, therefore to achieve the goal of building low-carbon footprint constructed facilities. Unfortunately, limited data have yet reported on the permanent deformation behaviour of the recycled materials in pavement, especially the effect of crumb rubber and rubber size with C&D aggregates on the permanent deformation behaviour in base and subbase layers. This paper provides unique laboratory information and testing results in this regard. In this study, two different groups of crumb rubber particles with sizes ranged from 400 to 600 µm (fine) and 15–20 mm (coarse) were separately added to 20 mm recycled concrete aggregate (RCA) and 20 mm crushed rock (CR) at 0.5, 1 and 2% by weight of the aggregates to study the effects of crumb rubber and rubber size on permanent deformation behaviour of RCA and CR aggregates. In particular, the permanent deformation behaviour of the RCA/CR with crumb rubber was investigated through the repeated load triaxial tests. It was observed that the CR samples should be avoided for use in base and subbase courses.

Effects of different crumb rubber sizes on the flowability and compressive strength of hybrid fibre reinforced ECC

The different sizes of crumb rubber have been used to investigate the effects on flowability and the compressive strength of the hybrid fibre reinforced engineered cementitious composite. Two sizes of crumb rubber 30 mesh and 1 to 3mm were used in partial replacement with the fine aggregate up to 60%. The experimental study was carried out through mathematical and statistical analysis by response surface methodology (RSM) using the Design Expert software. The response models have been developed and the results were validated by analysis of variance (ANOVA). It was found that finer sized crumb rubber inclusion had produced better workability and higher compressive strength when compared to the larger size and it was concluded that crumb rubber has negative effect on compressive strength and positive effect on workability. The optimization results are found to an approximately good agreement with the experimental results.

Influence of Particle and Interaction Effects of Different Sizes of Crumb Rubber on Rheological Performance Parameters of Binders

AbstractImprovement in rheological performance of asphalt binder with the addition of crumb rubber (CR) depends on the interaction between CR and the asphalt binder matrix. Overall, the change in a...

Partial replacement of conventional fine aggregate with crumb tyre rubber in structural concrete – effect of particle size on compressive strength and time dependent deformations

This paper presents results of a study into the effects of truck tyre crumb rubber particle size, as fine aggregate, on the compressive strength, shrinkage and creep behaviour of structural rubberised concrete. The study is motivated by a growing interest in the use of concrete with waste tyre rubber particles, rubberised concrete, for structural applications. Three tyre crumb rubber sizes (2.36, 1.18 and 0.425 mm) were used to replace 10% by volume of fine mineral aggregates to produce concrete with a target strength of 30 MPa. The concrete was cast water-cured for 28 days and tested for shrinkage and creep for 180 days. Half of the shrinkage and creep samples were sealed with a bitumen seal to prevent drying during testing. Results show a general a decrease in compressive strength with reduction in crumb rubber size. The strength decreases by 22%, 23% and 27% for the 2.36, 1.18 and 0.425 mm mix respectively. Preliminary results show a general increase in both shrinkage and creep deformations in both drying and sealed conditions. The observed increases were checked against the limits provided in design codes to assess the applicability of the material for structural purposes.

Compaction Characteristics, Unconfined Compressive Strengths, and Coefficients of Permeability of Fine-Grained Soils Mixed with Crumb-Rubber Tire

AbstractIn this study, five different weak soils were mixed with five different sizes of crumb rubber in six different proportions and used to understand the influence of the size and quantity of c...

Hardened properties of self-compacting concrete with different crumb rubber size and content

Abstract This paper aims at investigating the effect of crumb rubber size and content on hardened characteristics of self-compacting concrete. To this end, different self-compacting concrete mixtures were designed at constant water-to-binder ratio of 0.35 and 520 kg/m 3 of binder content. The class F fly ash was replaced with cement as 30% by weight. Six designated crumb rubber contents of 5%, 10%, 15%, 20%, and 25% and three different sized crumb rubbers (No. 18, No. 5, and mixed crumb rubber) were considered as experimental parameters. According to the obtained results, the use of crumb rubber had a negative effect on the hardened properties of self-compacting concretes and the significant improvement was achieved with addition of all tire wastes types, for ductility.

Regarding the influence of the particle size of crumb rubber from waste rubber on the physical and mechanical characteristics of reclaimed rubber

Thus, at present, a large amount of rubber waste cannot be higher harnessed due to recovery technologies used. Also, the requirements for new products of rubber worldwide are greater than the production capacity and the availability of raw materials. To offset this balance is necessary to improve technologies for recycling waste rubber so to can get regenerated rubber with the best mechanical physical characteristics. The main technology for obtaining the regenerated rubber is based on the rubber waste shredding and making the powder, so that it can be carried out de-vulcanization in autoclave. All the time it was monitored as the de-vulcanization process to be as economical and less polluting, and this requires that the sizes of the crumb rubber to be optimal. Thus, in the conducted researches was aimed to establish the particle size of crumb rubber from waste rubber so as to obtain an economical de-vulcanization, but also a reclaimed rubber with superior physical and mechanical characteristics. The organization of researches was made so that crumb of rubber waste was divided into 5 groups, bowing from crumb rubber with particle’s size of 1000 μm (RPS1), and reaching up to crumb rubber with particle’s size of 200 μm (RPS 5).

Use of Crumb Rubber as an Additive in Asphalt Concrete Mixture

As the rapidly growing number of vehicles in Indonesia, the waste of tire rubber becomes a major environmental concern. The use of crumb rubber, which is the recycled tire rubber, as an additive in hot mix asphalt mixture is considered as a sustainable construction method. The purpose of this study was to investigate the effect of adding crumb rubber to asphalt mixture using wet process. The laboratory hot mix asphalt design tests were done by Marshall Method procedure. In this study, two different crumb rubber contents (1% and 2% by weight of asphalt mixture) and two different crumb rubber sizes (#40 and #80) were investigated. A comparative study was done among the unmodified and modified asphalt concrete mixtures considering the Marshall Stability value and the volumetric properties. The results showed that crumb rubber is recommended as an additive in asphalt mixture, as all the test results are within the standard requirements. The addition of crumb rubber tended to increase the strength and quality of asphalt mixture. However, it should be more concern about durability of asphalt mixture because of the lower asphalt content in crumb rubber modified asphalt mixture.