scholarly journals An Analytical Mini-Review on the Compression Strength of Rubberized Concrete as a Function of the Amount of Recycled Tires Crumb Rubber

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1234 ◽  
Author(s):  
Luca Lavagna ◽  
Roberto Nisticò ◽  
Matteo Sarasso ◽  
Matteo Pavese
Keyword(s):  
Environmental Concern ◽  
Crumb Rubber ◽  
Research Field ◽  
Partial Substitution ◽  
Mechanical Resistance ◽  
Rubberized Concrete ◽  
Aggregate Fraction ◽  
Mechanical Responses ◽  
Acoustic Insulation ◽  
Technical Solutions

Since waste tires constitute a serious environmental concern, several studies are devoted to the use of finely divided recycled rubber for the production of rubberized concrete by partial substitution of the mineral aggregate fraction. The introduction of rubber into concrete presents several advantages (e.g., improvement of toughness and thermal/electrical/acoustic insulation capacities). Unfortunately, the addition of a high content of rubber into concrete causes an important loss of mechanical resistance of the final composite. In this context, several scientific studies are devoted to investigate the best technical solutions for favoring the interfacial adhesion between rubber and cement paste, but the interpretation of the literature is often misleading. To overcome this issue, the metadata extrapolated from the single scientific works were critically re-analyzed, forming reference diagrams where the variability fields of the different rubber concrete formulations (in terms of mechanical responses as a function of the rubber content) were defined and the best performances discussed. This study evidenced the twofold role of reference diagrams, able in both presenting the data in an unambiguous manner (for a successful comparison) and providing the guidelines for future works in this research field.

EFFECT OF CRUMB RUBBER ON CONCRETE STRENGTH AND CHLORIDE ION PENETRATION RESISTANCE

2015 ◽  
Vol 77 (32) ◽  
Author(s):  
Nurazuwa Md Noor ◽  
H. Hamada ◽  
Y. Sagawa ◽  
D. Yamamoto
Keyword(s):  
Structural Strength ◽  
Salt Water ◽  
Chloride Ion ◽  
Crumb Rubber ◽  
Rubberized Concrete ◽  
Migration Test ◽  
Ion Diffusion ◽  
Steady State Condition ◽  
Chloride Ion Penetration ◽  
Chloride Ion Diffusion

This paper present the effect of crumb rubber on its ability to produce concrete with structural strength when it was used directly from the plant without any treatment process. Crumb rubber was added as fine aggregates at 0%, 10%, 15% and 20% of sand volume meanwhile silica fume was added at 10% by cement weight. Three main series of concrete namely rubberized concrete with water-to-cement ratio of 50% and 35% was design and development of compressive strength was observed from day 7 until 91 days. Also, effectiveness of crumb rubber under flexural strength and splitting tensile strength was studied at 28 days curing age. Effect of crumb rubber on durability performance was done on chloride ion penetration resistance performance by migration test and by immersion in salt water. Chloride ion diffusion in rubberized concrete by migration test was carried out under steady state condition using effective diffusion coefficient, De meanwhile, immersion test in salt water was conducted under non-steady state condition using apparent diffusion coefficient, Da. Results showed that compressive strength was decrease with the increasing of crumb rubber in the mixture.  Even though the strength were reducing with the inclusion of crumb rubber, the reduction were less than 50% and it achieved acceptable structural strength. Chloride transport characteristics were improved by increasing amount of CR and rubberized concrete with w/c = 0.35 gave better resistance against chloride ion compared to w/c = 0.50 with more than 50% difference. Silica fume provide slightly strength increment compared to normal rubberized concrete and the same behavior was observed during chloride ion diffusion test.

scholarly journals Cyclodextrins and Cyclodextrin Derivatives as Green Char Promoters in Flame Retardants Formulations for Polymeric Materials. A Review

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 664 ◽  
Author(s):  
Maria Paola Luda ◽  
Marco Zanetti
Keyword(s):  
Flame Retardants ◽  
Environmental Concern ◽  
Fire Retardant ◽  
Polymeric Materials ◽  
Poly Lactic Acid ◽  
Mechanical Resistance ◽  
Self Healing ◽  
Cyclodextrin Derivatives ◽  
The Matrix ◽  
Fire Retardance

Polymers are intrinsically flammable materials; hence, fire retardance (FR) is required in their most common applications (i.e., electronic and construction, to mention some). Recently, it has been reported that cyclodextrin (CD) and cyclodextrin derivatives are beginning to be introduced into Intumescent Fire Retardant (IFR) formulations in place of pentaerythritol, which is used in IFRs that are currently on the market. Since IFRs are of less environmental concern than their hazardous halogen containing counterparts, the use of natural origin compounds in IFRs provides a way to comply with green chemistry issues. BCD and BCD derivatives presence in IFR mixtures promotes a higher yield of blowing gases and char when polymeric materials undergo combustion. Both processes play important roles in intumescence. The key rule to obtain in insulating compact char is the good dispersion of the nanoparticles in the matrix, which can be achieved by functionalizing nanoparticles with BCD derivatives. Moreover, CD derivatives are attractive because of their nanosized structure and their ability to form inclusion complexes with many compounds used as FR components, reducing their release to the environment during their shelf life of FR items. Often, fire retardance performed by BCD and BCD derivatives accompanies other relevant properties, such as improved mechanical resistance, washability resistance, self healing ability, thermal conductivity, etc. The application of CD fire retardant additives in many polymers, such as poly(lactic acid), poly(propylene), poly(vinyl acetate), poly(methyl methacrylate), linear low density poly(ethylene), polyamides, and polyesters are comprehensively reviewed here.

scholarly journals Microwave Devulcanized Crumb Rubbers in Polypropylene Based Thermoplastic Dynamic Vulcanizates

Polymers ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 767 ◽  
Author(s):  
Dániel Simon ◽  
István Halász ◽  
József Karger-Kocsis ◽  
Tamás Bárány
Keyword(s):  
Processing Parameters ◽  
Crumb Rubber ◽  
Partial Substitution ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Feeding Method ◽  
Rubber Compounds ◽  
Continuous Extrusion ◽  
3D Molecular Structure ◽  
Styrene Butadiene

Because of the chemically crosslinked 3D molecular structure of rubbers, their recycling is a challenging task, especially when cost efficiency is also considered. One of the most straightforward procedures is the grinding of discarded rubber products with subsequent devulcanization. The devulcanized rubber can be used as a feedstock for fresh rubber compounds or can be blended with uncured virgin rubber and thermoplastic polymers to form thermoplastic dynamic vulcanizates (TDVs). TDVs combine the beneficial (re)processability of thermoplastics and the elastic properties of rubbers. Our current work focuses on the development of polypropylene (PP)-based TDVs with the use of a tire model rubber (MR) composed of natural rubber (NR) and styrene-butadiene rubber (SBR) in a ratio of 70/30. The research target was the partial substitution of the above fresh MR by microwave devulcanized crumb rubber (dCR). TDVs were produced by continuous extrusion, and the effects of composition (PP/MR/dCR = 40/60/0…50/35/15) and processing parameters (different screw configurations, temperature profiles, the feeding method of PP) were investigated. Results showed that the fresh rubber compound can be replaced up to 10 wt % without compromising the mechanical properties of the resulting TDV.

Engineering properties of rubberized concrete

1992 ◽  
Vol 19 (5) ◽  
pp. 912-923 ◽  
Author(s):  
Neil N. Eldin ◽  
Ahmed B. Senouci
Keyword(s):  
Plain Concrete ◽  
Crumb Rubber ◽  
Engineering Properties ◽  
Unit Weight ◽  
Rubberized Concrete ◽  
Portland Cement Concrete ◽  
Freezing And Thawing ◽  
Scrap Tire ◽  
Plastic Energy ◽  
Freezing And Thawing Cycles

Growing piles of discarded tires are potential sources of fire and health hazards. The current disposal methods are wasteful and costly. As a possible solution to the problem of scrap-tire disposal, an experimental study was conducted to examine the potential use of rubber aggregate (tire chips and crumb rubber) as mineral aggregate substitute in Portland cement concrete mixes. The research focused on determining the strength characteristics of rubberized concrete and examined the relationship between the size, percentage, and shape of rubber aggregate and the strength measured.Rubberized concrete was found to possess good esthetics, acceptable workability, and a smaller unit weight than plain concrete. However, it exhibited low compressive and tensile strengths and lower resistance to repeated freezing and thawing cycles than that of plain concrete. A statistical analysis of the experimental data suggested that only the percentage by volume of rubber in the mix has a significant effect on strength. The size and shape was found insignificant. Unlike plain concrete, rubberized concrete did not demonstrate the typical brittle failure. It exhibited a ductile, plastic failure, and showed the ability to absorb a large amount of plastic energy under compressive and tensile loads. Key words: rubberized concrete, concrete properties, compression, durability, failure, modulus of elasticity, slump, tension, toughness, workability.

scholarly journals Prediction Models for the Mechanical Properties of Self-Compacting Concrete with Recycled Rubber and Silica Fume

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1821 ◽  
Author(s):  
Robert Bušić ◽  
Mirta Benšić ◽  
Ivana Miličević ◽  
Kristina Strukar
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Silica Fume ◽  
Prediction Models ◽  
Crumb Rubber ◽  
Fine Aggregate ◽  
Rubberized Concrete ◽  
Self Compacting Concrete ◽  
Recycled Rubber ◽  
European Standards

The paper aims to investigate the influence of waste tire rubber and silica fume on the fresh and hardened properties of self-compacting concrete (SCC) and to design multivariate regression models for the prediction of the mechanical properties of self-compacting rubberized concrete (SCRC). For this purpose, 21 concrete mixtures were designed. Crumb rubber derived from end-of-life tires (grain size 0.5–3.5 mm) was replaced fine aggregate by 0%, 5%, 10%, 15%, 20%, 25%, and 30% of total aggregate volume. Silica fume was replaced cement by 0%, 5%, and 10% of the total cement mass. The optimal replacement level of both materials was investigated in relation to the values of the fresh properties and mechanical properties of self-compacting concrete. Tests on fresh and hardened self-compacting concrete were performed according to the relevant European standards. Furthermore, models for predicting the values of the compressive strength, modulus of elasticity, and flexural strength of SCRC were designed and verified with the experimental results of 12 other studies. According to the obtained results, mixtures with up to 15% of recycled rubber and 5% of silica fume, with 28 days compressive strength above 30 MPa, were found to be optimal mixtures for the potential future investigation of reinforced self-compacting rubberized concrete structural elements.

scholarly journals Low-Carbon Composite Based on MOC, Silica Sand and Ground Porcelain Insulator Waste

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 829 ◽  
Author(s):  
Adam Pivák ◽  
Milena Pavlíková ◽  
Martina Záleská ◽  
Michal Lojka ◽  
Anna-Marie Lauermannová ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Mineralogical Composition ◽  
Experimental Tests ◽  
Carbon Composite ◽  
Silica Sand ◽  
Partial Substitution ◽  
Mechanical Resistance ◽  
Low Carbon ◽  
Technical Parameters ◽  
Substitution Ratio

Magnesium oxychloride cement-based composites (MOC) with silica sand/porcelain waste blended fillers were designed and tested. The objective of the presented research was to design and test low carbon, eco-friendly and viable alternatives to Portland cement-based materials. To make new materials environmentally acceptable and sustainable, silica sand applied in the reference composite material was partially substituted by ground porcelain waste (PW) coming from used electrical insulators. The sand substitution ratio was 5, 10, and 15 vol.%. The chemical and mineralogical composition, morphology, and particle size distribution of porcelain waste were measured. For silica sand, porcelain waste, and MgO, specific density, loose bulk density, and Blaine fineness were determined. The effect of porcelain waste on the workability of fresh composite mixtures was characterized by spread diameter. The composites were characterized by their basic structural, mechanical, hygric, and thermal properties. The phase composition and thermal stability at high temperatures of MOC/porcelain waste pastes were also analyzed. Fourier-transform infrared spectroscopy (FT-IR) analysis helped to indicate main compounds formed within the precipitation of MOC phases and their reaction with porcelain waste. The usage of porcelain waste greatly decreased the porosity of composite matrix, which resulted in high mechanical resistance and reduced and decelerated water imbibition. The 10% sand substitution with porcelain waste brought the best mechanical resistance and the lowest water absorption due to the formation of amorphous phases, water-insoluble aluminosilicates. In case of the thermal performance of the examined composites, the low thermal conductivity of porcelain waste was the contradictory parameter to porosity and the high thermal stability of the phases present in porcelain slightly decreased the thermal decomposition of composites with porcelain waste dosage. Based on the results emerged from the experimental tests it was concluded that the partial substitution of silica sand in MOC composites enabled the development of materials possessing interesting and advanced function and technical parameters.

Correlation of strength, rubber content, and water to cement ratio in rubberized concrete

2005 ◽  
Vol 32 (6) ◽  
pp. 1075-1081 ◽  
Author(s):  
Ashraf M Ghaly ◽  
James D Cahill IV
Keyword(s):  
Compressive Stress ◽  
Experimental Testing ◽  
Concrete Strength ◽  
Crumb Rubber ◽  
Test Results ◽  
Rubberized Concrete ◽  
Rubber Content ◽  
Research Project ◽  
Conventional Concrete ◽  
Cement Ratio

Waste rubber tires that cannot be processed for useful applications are numbered in the millions around the world. The build up of old rubber tires in landfills is commonly considered a major threat to the environment, and it is unquestionably a burden on landfill space. This research project was an investigation into the possibility of using fine rubber particles in concrete mixtures. The experimental testing program was designed to study the effect of the addition of crumb rubber, as replacement of a portion of fine aggregates (sand), on the strength of concrete. Rubber was added to concrete in quantities of 5%, 10%, and 15% by volume of the mixture. Three different water/cement ratios were used: 0.47, 0.54, and 0.61. A total of 180 concrete cubes were made. The cubes were tested in compression at 1, 7, 14, 21, and 28 d with the load continuously and automatically measured until failure. The load values were used to calculate compressive stress as related to different rubber contents and water/cement ratios. Compression test results were used to develop several plots relating rubber content and water/cement ratio to compressive stress of concrete. Test results gathered in this research project indicated that the addition of crumb rubber to concrete results in a reduced strength as compared with that of conventional concrete. Based on the experimental results, correlations have been developed to estimate the reduction in concrete strength as a function of the rubber content in the mix.Key words: compressive strength, concrete, crumb rubber, rubberized concrete.

Sign in / Sign up

Export Citation Format

Share Document