scholarly journals THE STRENGTH OF CONCRETE WITH AN ELASTIC ADDITIVE OF TIRES RUBBER WASTE UNDER CYCLIC LOADING

2009 ◽  
Vol 1 (4) ◽  
pp. 172-182
Author(s):  
Gintautas Skripkiūnas ◽  
Audrius Grinys
Keyword(s):  
Compressive Strength ◽  
Cyclic Load ◽  
Internal Stresses ◽  
Cement Stone ◽  
Cyclic Loads ◽  
Rubberized Concrete ◽  
Rubber Waste ◽  
Significant Difference ◽  
Residual Strains ◽  
Concrete Matrix

Concrete strength under cyclic loads is much lower compared to short-term loading strength because cyclic loads stimulate the growth of microcracks in the cement matrix, reduce the adherence of cement stone and aggregates and cause higher creep deformations. The paper presents the deformations of samples with or without a rubber waste additive subjected to cyclic loads and determined by the methods developed during research. The obtained results show that relative plastic strains under cyclic load and relative residual strains after the removal of the load depend on the rubber additive. Relative strains in the rubberized concrete samples loaded at 70% prism compressive strength are 63% higher and residual strains after the removal of the load are 234% higher. When the samples are loaded at 80% of prism compressive strength, relative strains and residual strains after the removal of the load in concrete with the rubber additive are respectively 56% and even 360% higher if compared to the samples without the rubber additive. When the samples are loaded at 90% of prism compressive strength, the obtained respective relative strains are 63% and 219% higher compared to the samples without rubber additives. An increase in relative plastic and residual strains shows the influence of the rubber additive on the stress-strain behaviour of concrete subjected to cyclic loads. The conducted investigation has revealed that concrete with rubber waste additive under cyclic loads changes ultimate strains. We can see a significant difference in the yield deformations leading to the ultimate failure of concrete with or without the rubber additive. When the samples of rubberized concrete are loaded at 70% of prism compressive strength, the longitudinal ultimate strains are 36% higher; loading at 80% results in 47% higher strains and that at 90% results in 42% higher strains compared to the non-rubberized concrete samples. The analysis of changes in deformation conducted by the created method does not give a precise forecast as to the number of cycles that one or another type of concrete will resist under a certain load. Nevertheless, the obtained changes in deformations enable to make rather precise decisions with regard to the ability of concrete to absorb cyclic stresses with the higher strains of the concrete matrix. A detailed analysis of the test results has revealed the following tendencies: concrete with rubber additives has better deformation abilities under cyclic loads because of bigger plastic (residual) strains and bigger ultimate strains. This leads to the presumption that rubber additives present in the concrete matrix are able to absorb cyclic-load-stimulated internal stresses driving the concrete fragmentation process.

scholarly journals Performance of self-compacting rubberized concrete

2018 ◽  
Vol 149 ◽  
pp. 01070 ◽  
Author(s):  
Bensaci Hamza ◽  
Menadi Belkacem ◽  
Kenai Said ◽  
Yahiaoui Walid
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Partial Substitution ◽  
Fine Aggregate ◽  
Rubberized Concrete ◽  
Rubber Waste ◽  
Waste Tyres ◽  
Hardened State ◽  
Hardened Properties ◽  
And Storage

Used tyre rubber wastes present a serious environmental problem of pollution and storage. The recycling of this waste in the industry of construction could be an appropriate solution to produce an eco-concrete and could contribute to the improvement of some of its properties. This paper aims to study the possibility of using tyre rubber waste as fine aggregate replacement in self-compacting concrete (SCC). Fines rubber particles of 0-2 mm of waste tyres were added SCC mixtures as a partial substitution of the total volume of sand at different percentages (5, 10, 15, 20 and 30%). The influence of fines rubber of used tyres on fresh and hardened properties of the SCC was investigated. The fresh properties of SCC were performed by using slump-flow, T50 flow time, L-box, V-funnel and segregation resistance tests. Characteristics of the hardened state were obtained by compressive strength and thermal conductivity. The experimental results showed that the inclusion of fines rubber in SCC decreases the workability, reduced its passing capacity and increases the possibility of blocking. A decrease in compressive strength is observed with the increase in rubber content. On the other hand, the incorporation of the rubber fines aggregates enhances in a remarkably way the thermal conductivity.

scholarly journals LOAD-BEARING CAPACITY OF COMPRESSED CONCRETE ELEMENTS SUBJECTED TO REPEATED LOAD STRENGTHENED WITH CFRP MATERIALS

2012 ◽  
Vol 18 (4) ◽  
pp. 590-599 ◽  
Author(s):  
Wojciech Trapko ◽  
Tomasz Trapko
Keyword(s):  
Bearing Capacity ◽  
Cyclic Load ◽  
Young Modulus ◽  
Experimental Investigations ◽  
Cyclic Loads ◽  
Load History ◽  
Load Bearing Capacity ◽  
Residual Strains ◽  
Repeated Load ◽  
Concrete Elements

This paper presents the results of experimental investigations of compressed concrete elements behaviour subjected to monotonic and cyclic load strengthened with CFRP materials. Two types of CFRP strengthening were applied during the experiment – longitudinal strips and/or transverse sheets. The results obtained allowed to draw conclusions concerning the possibility of representing a stress-strain monotonic curve with a curve of cyclic strains. The influence of load history on strain parameters of the investigated elements was found. The influence of the strengthening pattern and the state of effort on Young modulus and residual strains was analyzed. Moreover, observations were made of the disadvantageous effect of cyclic loads on strengthening durability, which lead to deformation or partial delamination of external CFRP reinforcement.

scholarly journals Flexural Behavior of Rubberized Reinforced Concrete Beams

2018 ◽  
Vol 7 (4.20) ◽  
pp. 316 ◽  
Author(s):  
Adel A. Al-Azzawi ◽  
Dalia Shakir ◽  
Noora Saad
Keyword(s):  
Ultimate Load ◽  
Coarse Aggregate ◽  
Concrete Beams ◽  
Fiber Content ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Rubberized Concrete ◽  
Normal Concrete ◽  
Rubber Material ◽  
Rubber Waste

In Iraq, the use of rubber waste material in concrete is an interesting topic due to its availability in large volumes. Researches of applications of rubber waste in concrete have been increased since 2003. Many studies carried out to investigate the performance of concrete using different ratios of rubber as a replacement to fine or coarse aggregate. In this research, rubber wastes from scrapped tires have been added as fiber to concrete mix with presence of 0.5% superplasticizer. The flexural behavior of concrete beams, mechanical properties of concrete and workability of concrete mixes have been studied. Rubber fibers ranging from (2-4) mm were added in percentages of 0.5% and 1%) of the cement weight. The results have demonstrated that the addition of rubber material as fibers in natural aggregate concrete enhances its ductility, compressive strength and tensile strength compared to the normal concrete. The effect of rubber fiber content is found to be significant on the behavior of tested beams. If the fiber content increased from 0 to 0.5% the cracking load increased by 60 % and ultimate load increased by 21%. For rubberized concrete, if the fiber content increased from 0.5 to 1.0%, the cracking load decreased 7% and ultimate load increased by 4%.   

scholarly journals PROPERTIES OF MORTARS CONTAINING TIRE RUBBER WASTE AND EXPANDED POLYSTYRENE (EPS)

2018 ◽  
pp. 219-225 ◽  
Author(s):  
Adriane Pczieczek ◽  
Adilson Schackow ◽  
Carmeane Effting ◽  
Itamar Ribeiro Gomes ◽  
Talita Flores Dias
Keyword(s):  
Compressive Strength ◽  
Specific Gravity ◽  
Water Absorption ◽  
Expanded Polystyrene ◽  
Fine Aggregate ◽  
Tire Rubber ◽  
Air Content ◽  
Rubber Waste ◽  
Hardened State ◽  
Entrained Air

This study aims to evaluate the application of discarded tire rubber waste and Expanded Polystyrene (EPS) in mortar. For mortars fine aggregate was replaced by 10%, 20% and 30% of rubber and, 7.5% and 15% of EPS. We have verified the consistency, density, amount of air and water retentitivity in fresh state. The compressive strength, water absorption, voids ratio and specific gravity have been also tested in hardened state. The application of rubber powder contributed to the increase in entrained air content and in reducing specific gravity, as well as reducing compressive strength at 28 days. The addition of EPS also contributed to the increase of workability, water absorption and voids ratio, and decreased density and compressive strength when compared to the reference mortar. The use of rubber waste and EPS in mortar made the material more lightweight and workable. The mortars mixtures containing 10% rubber and 7.5% EPS showed better results.

scholarly journals Experimental Study on Strength of Pervious Concrete by Using Fine Aggregate

2021 ◽  
Vol 9 (12) ◽  
pp. 895-897
Author(s):  
Atif Jawed
Keyword(s):  
Compressive Strength ◽  
Void Ratio ◽  
Rice Husk Ash ◽  
Pervious Concrete ◽  
Void Content ◽  
Fine Aggregate ◽  
Coarse Aggregates ◽  
Fine Aggregates ◽  
Flow Through ◽  
Concrete Matrix

Abstract: Pervious concrete is a special type of concrete, which consists of cement, coarse aggregates, water and if required and other cementations materials. As there are no fine aggregates used in the concrete matrix, the void content is more which allows the water to flow through its bodyThe main aim of this project was to improve the compressive strength characteristics of pervious concrete. But it can be noted that with increase in compressive strength the void ratio decreases. Hence, the improvement of strength should not affect the porosity property because it is the property which serves its purpose. In this investigation work the compressive strength of pervious concrete is increased by a maximum of 18.26% for 28 days when 8% fine aggregates were added to standard pervious concrete Keywords: W/C ratio, pervious Concrete, sugarcane bagasse’s ash, rice husk ash compressive strength, fine aggregates

scholarly journals Strength and abrasive properties of andesite: relationships between strength parameters measured on cylindrical test specimens and micro-Deval values—a tool for durability assessment

2020 ◽  
Author(s):  
Balázs Czinder ◽  
Ákos Török
Keyword(s):  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Test Results ◽  
Strength Parameters ◽  
Data Set ◽  
Freeze Thaw ◽  
Laboratory Test Results ◽  
Significant Difference ◽  
Abrasive Properties ◽  
Water Saturated

Abstract Aggregates are necessary materials for the construction industry. Owing to their favourable properties, andesites are frequently used rock materials; hence, the investigation of their mechanical and aggregate properties has great significance. This paper introduces the analyses of 13 Hungarian andesite lithotypes. The samples were collected from six andesite quarries in Hungary. Cylindrical specimens and aggregate samples with 10.0/14.0-mm-sized grains were made from rock blocks. The specimens were tested in dry, water-saturated and freeze–thaw subjected conditions. Bulk density, uniaxial compressive strength, modulus of elasticity, indirect tensile strength and water absorption were measured. The abrasion resistance was tested by micro-Deval tests. The flakiness indexes of the samples were also measured. The data set of the laboratory test results provided input for further, one- and two-variable statistical analyses. According to the test results, there is no significant difference between the strength parameters measured in water-saturated and in freeze–thaw subjected conditions. The correlation and regression analyses revealed relationships between some rock mechanical parameters, as well as between micro-Deval coefficient and uniaxial compressive strength.

Dynamic Behavior of Pure Squeeze Films in Narrow Porous Bearings

1974 ◽  
Vol 96 (3) ◽  
pp. 361-364 ◽  
Author(s):  
P. R. K. Murti
Keyword(s):  
Dynamic Behavior ◽  
Cyclic Load ◽  
Journal Bearing ◽  
Load Capacity ◽  
Squeeze Film ◽  
Closed Form Expression ◽  
Cyclic Loads ◽  
Eccentricity Ratio ◽  
Form Expression ◽  
Bearing Material

The dynamic behavior of squeeze film in a narrow porous journal bearing under a cyclic load is analyzed. A thin-walled bearing with a nonrotating journal is considered and a closed form expression for the pressure distribution is derived. The locus of the journal center is found by numerical methods and it is established with an example that actual contact between the journal and bearing can be avoided by appropriate design of the bearing. Consequently, it is proved that pure squeeze films have a load capacity only under cyclic loads. The analysis also reveals that the permeability of the bearing material and the wall thickness of the bearing influence significantly the operating eccentricity ratio.

scholarly journals Behavior of unconfined and CFRP confined rubberized concrete

2019 ◽  
Vol 15 (1) ◽  
pp. 65-83
Author(s):  
Rana Faisal Tufail ◽  
Xiong Feng ◽  
Muhammad Zahid
Keyword(s):  
Compressive Strength ◽  
Axial Strain ◽  
High Strength ◽  
Deformation Capacity ◽  
Rubberized Concrete ◽  
Conventional Concrete ◽  
Externally Bonded ◽  
Axial Compressive Strength ◽  
Strength And Deformation ◽  
Strength Models

Abstract The use of rubberized concrete (RuC) is an effective environmental approach to reduce the amount of scrap tires around the world. However, there are serious concerns regarding the compressive strength of RuC. This article investigates the use of externally bonded carbon fiber reinforced polymer (CFRP) jackets on RuC to develop a novel high strength and deformable CFRP confined RuC. In this study, 66 RuC cylinders were cast with 0, 10, 20, 30, 40 and 50% fine or coarse rubber to replace mineral aggregates. The RuC cylinders were then confined with one, two or three layers of CFRP jackets. The results indicated 208% high lateral strains in unconfined RuC as compared to the conventional concrete. CFRP jacketing was highly effective for enhancing the compressive strength and deformation capacity of RuC, where high compressive strength enhancement of 52 MPa and deformation capacity (317% axial strain) was achieved. The confined compressive strength test results were compared with the strength models to assess their validity for CFRP confined RuC. An analysis-oriented strength model was developed to predict the axial compressive strength of RuC confined by CFRP jackets. Overall, this study demonstrated the potential of using CFRP-confined RuC as a new structural material with improved strength and deformation.

Development of Cement Compositions with a Finely Dispersed Additive for Consolidation of Soil by the Injection

2019 ◽  
Vol 974 ◽  
pp. 149-155
Author(s):  
Irina V. Kozlova ◽  
Alexey E. Bespalov ◽  
Alexandra V. Bespalova
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Mechanical Characteristics ◽  
Cement Stone ◽  
Soil Consolidation ◽  
Injection Solution ◽  
Concentrated Load ◽  
Reduced Viscosity ◽  
Injection Technology ◽  
Physical And Mechanical Characteristics

Cement compositions prepared by mixing cement with a stabilized finely dispersed slag suspension, which allow improving the structural, physical and mechanical characteristics of the cement stone are considered. On the first day of hardening, the strength of modified specimens increased by 54%, at the grade age - by 43%, and the porosity decreased by 13.8 and 17.3%, respectively. The possibility of obtaining an injection solution for soil consolidation on the basis of Portland cement and a stabilized slag suspension with the concentration of a finely dispersed slag of 50 g/l is considered. Studies have shown that the injection solution under study has reduced viscosity and sedimentation, increased compressive strength. After 28 days of hardening, the strength was 14.2 MPa, which is higher than the recommended values ​​for consolidation of soil under the foundations (4-6 MPa), and at a concentrated load, for the base under the foundations of the columns (9-10 MPa). The data obtained allows considering an injection solution based on Portland cement and slag suspension for the use in the injection technology of soil consolidation.

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