Experimental Evaluation of Untreated and Pretreated Crumb Rubber Used in Concrete

The present research aims at evaluating the mechanical performance of untreated and treated crumb rubber concrete (CRC). The study was also conducted to reduce the loss in mechanical properties of CRC. In this study, sand was replaced with crumb rubber (CR) with 0%, 5%, 10%, 15%, and 20% by volume. CR was treated with NaOH, lime, and common detergent for 24 h. Furthermore, water treatment was also carried out. All these treatments were done to enhance the mechanical properties of concrete that are affected by adding CR. The properties that were evaluated are compressive strength, indirect tensile strength, unit weight, ultrasonic pulse velocity, and water absorption. Compressive strength was assessed after 7 and 28 days of curing. The mechanical properties were decreased by increasing the percentage of the CR. The properties were improved after the treatment of CR. Lime treatment was found to be the best treatment of all four treatments followed by NaOH treatment and water treatment. Detergent treatment was found to be the worse treatment of all four methods of treatment. Despite increasing the strength it contributed to strength loss.

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COMPRESSIVE STRENGTH EVALUATION OF LIGHTWEIGHT CONCRETE WITH EXPANDED GLASS AGGREGATE BY ULTRASONIC PULSE VELOCITY METHOD

Proceedings of International Structural Engineering and Construction ◽

10.14455/isec.res.2020.7(1).mat-10 ◽

2020 ◽

Vol 7 (1) ◽

Author(s):

Christopher Collins ◽

Saman Hedjazi

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Lightweight Concrete ◽

Lightweight Aggregate ◽

Ultrasonic Pulse Velocity ◽

Ultrasonic Pulse ◽

Pulse Velocity ◽

Normal Weight ◽

Unit Weight ◽

Normal Weight Concrete

In the present study, a non-destructive testing method was utilized to assess the mechanical properties of lightweight and normal-weight concrete specimens. The experiment program consisted of more than a hundred concrete specimens with the unit weight ranging from around 850 to 2250 kg/m3. Compressive strength tests were performed at the age of seven and twenty eight days. Ultrasonic Pulse Velocity (UPV) was the NDT that was implemented in this study to investigate the significance of the correlation between UPV and compressive strength of lightweight concrete specimens. Water to cement ratio (w/c), mix designs, aggregate volume, and the amount of normal weight coarse and fine aggregates replaced with lightweight aggregate, are the variables in this work. The lightweight aggregate used in this study, Poraver®, is a product of recycled glass materials. Furthermore, the validity of the current prediction methods in the literature was investigated including comparison between this study and an available expression in the literature on similar materials, for calculation of mechanical properties of lightweight concrete based on pulse velocity. It was observed that the recently developed empirical equation would better predict the compressive strength of lightweight concrete specimens in terms of the pulse velocity.

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Effect of high temperature on SCC containing fly ash

Challenge Journal of Concrete Research Letters ◽

10.20528/cjcrl.2021.01.001 ◽

2021 ◽

Vol 12 (1) ◽

pp. 1

Author(s):

Mehmet Canbaz ◽

Erman Acay

Keyword(s):

Compressive Strength ◽

High Temperature ◽

Fly Ash ◽

Concrete Strength ◽

Experimental Studies ◽

Strength Loss ◽

Ultrasonic Pulse Velocity ◽

Pulse Velocity ◽

Unit Weight ◽

Self Compacting Concrete

The effect of high temperature on self-compacting concrete, which contains different amounts of fly ash, has been investigated. By considering the effect of concrete age and increased temperatures, the optimum fly ash-cement ratio for the optimum concrete strength is determined using experimental studies. Self-compacting concrete specimens are produced, with fly ash/cement ratios of 0%, 20% and 40%. Specimens were cured for 28, 56 and 90 days. After curing was completed, the specimens were subjected to temperatures of 20°C, 100°C, 400°C, 700°C and 900°C for three hours. After the cooling process, tests were performed to determine the unit weight, ultrasonic pulse velocity and compressive strength of the specimens. According to the experiment results, an increase in fly ash ratio causes a decrease in the compressive strength of self-compacting concrete. However, it positively contributes to self-compaction and strength loss at high temperatures. The utilization of fly ash in concrete significantly contributes to the environment and the economy. For this reason, the addition of 20% fly ash to concrete is considered to be effective.

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Attempts to Improve the Subsurface Properties of Horizontally-Formed Cementitious Composites Using Tin(II) Fluoride Nanoparticles

Coatings ◽

10.3390/coatings10010083 ◽

2020 ◽

Vol 10 (1) ◽

pp. 83 ◽

Cited By ~ 2

Author(s):

Kamil Krzywiński ◽

Łukasz Sadowski ◽

Jacek Szymanowski ◽

Andrzej Żak ◽

Magdalena Piechówka-Mielnik

Keyword(s):

Tensile Strength ◽

Compressive Strength ◽

Abrasion Resistance ◽

Mechanical Performance ◽

Reference Sample ◽

Ultrasonic Pulse Velocity ◽

Ultrasonic Pulse ◽

Pulse Velocity ◽

Cementitious Composites ◽

Fluoride Nanoparticles

This article presents studies that were performed in order to improve the subsurface properties of horizontally-formed cementitious composites using tin(II) fluoride nanoparticles. The main aim of the study was to solve the problem of the decrease in subsurface properties caused by mortar bleeding and the segregation of the aggregate along the height of the overlay. The article also aims to highlight the patch grabbing difficulties that occur during the process of forming horizontally-formed cementitious composites. Four specimens were analyzed: one reference sample and three samples modified with the addition of 0.5, 1.0, and 1.5% of tin(II) fluoride nanoparticles in relation to the cement mass. To analyze the mechanical properties of the specimens, non-destructive (ultrasonic pulse velocity) and destructive tests (flexural tensile strength, compressive strength, abrasion resistance, pull-off strength) were performed. It was indicated that due to the addition of the tin(II) fluoride, it was possible to enhance the subsurface tensile strength and abrasion resistance of the tested cementitious composites. To confirm the obtained macroscopic results, the porosity of the subsurface was measured using SEM. It was also shown that the addition of the tin(II) fluoride nanoparticles did not reduce its flexural and compressive strength. The results show that horizontally-formed cementitious composites with the addition of 1.0% of tin(II) fluoride nanoparticles in relation to the cement mass obtained the most effective mechanical performance, especially with regard to subsurface properties.

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Utilization of ceramic waste in the production of Khorasan mortar

Challenge Journal of Structural Mechanics ◽

10.20528/cjsmec.2019.03.001 ◽

2019 ◽

Vol 5 (3) ◽

pp. 80

Author(s):

Hasan Selim Şengel ◽

Mehmet Canbaz ◽

Ersin Güler

Keyword(s):

Compressive Strength ◽

Bending Strength ◽

Ceramic Powder ◽

Geographical Area ◽

Ultrasonic Pulse Velocity ◽

Ultrasonic Pulse ◽

Pulse Velocity ◽

Ceramic Production ◽

Unit Weight ◽

Historical Structures

Khorasan mortar was used in almost all of the historical structures in the geographical area of turkey. It is still used in the renovation of these structures. Water, lime, baked clay is used in the production of Khorasan by breaking and grinding. Crushed brick and tiles are preferred as baked clay. In this study, the usability of ceramic wastes as baked clay was investigated. An important part of ceramic production is made especially in Eskişehir and its vicinity. 10% of ceramic production shows up as wastes because of various reasons. These wastes which are under 20 mm are crushed in the jaw breakers and these which are under 150 mm are grinned in grinders, transformed to powder and then mixed with hydrated lime and water in various proportions, in this way Khorasan mortars are obtained. In mortar production, crushed ceramic-ceramic powder ratio, ceramic-lime ratio were changed and the most suitable ratios were tried to be found. Samples taken from these mortars which are 4 cm x 4 cm x 16 cm in size are removed after a day from the mold and kept in humid environment. Physical and mechanical properties such as unit weight, ultrasonic pulse velocity, bending strength, compressive strength of the mortar were determined. As a result of the experiments, the unit weights range was between 1.5–1.65 kg/dm3, the ultrasonic pulse velocity rates range from 1.3–1.9 km/h, the range of bending strengths was from 0.25–1.05 MPa, and compressive strength has changed in the range of 7.5–10.5 MPa. With the work done, it is recommended to use a high percentage of lime while using ceramic wastes in the process of producing Khorasan mortar.

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Effect of Hollow Corundum Microspheres Additive on Physical and Mechanical Properties and Thermal Shock Resistance Behavior of Bauxite Based Refractory Castable

Materials ◽

10.3390/ma14164736 ◽

2021 ◽

Vol 14 (16) ◽

pp. 4736

Author(s):

Rimvydas Stonys ◽

Jurgita Malaiškienė ◽

Jelena Škamat ◽

Valentin Antonovič

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Thermal Shock ◽

Modulus Of Elasticity ◽

Thermal Shock Resistance ◽

Visual Analysis ◽

Ultrasonic Pulse Velocity ◽

Ultrasonic Pulse ◽

Pulse Velocity ◽

Shock Resistance

This paper analyses the effect of hollow corundum microspheres (HCM) on both physical-mechanical properties (density, ultrasonic pulse velocity, modulus of elasticity, and compressive strength) and thermal shock resistance behavior of refractory medium cement castable with bauxite aggregate. Moreover, the scanning electron microscopy (SEM) results of HCM and refractory castable samples are presented in the paper. It was found that the replacement of bauxite of 0–0.1 mm fraction by HCM (2.5%, 5%, and 10% by weight of dry mix) had no significant effect on the density and compressive strength of castable, while the modulus of elasticity decreased by 15%. Ultrasonic pulse velocity (Vup) values and the visual analysis of the samples after thermal cycling showed that a small amount of HCM in composition of refractory castable could reduce the formation and propagation of cracks and thus increase its thermal shock resistance.

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Experimental study of wood shaving addition in mortar and statistical modeling on selected effects

Journal of the Mechanical Behavior of Materials ◽

10.1515/jmbm-2017-0013 ◽

2017 ◽

Vol 26 (1-2) ◽

pp. 55-63 ◽

Cited By ~ 3

Author(s):

Anastasia Sotiropoulou ◽

Stamatia Gavela ◽

Nikolaos Nikoloutsopoulos ◽

Dimitra Passa ◽

Georgios Papadakos

Keyword(s):

Compressive Strength ◽

Ultrasonic Pulse Velocity ◽

Ultrasonic Pulse ◽

Pulse Velocity ◽

Unit Weight ◽

Wood Shavings ◽

Fine Aggregates ◽

Volume Measurements ◽

Sigmoidal Model ◽

Selected Effects

AbstractIn the frame of an extended research program dealing with wood shavings utilization in mortar, a set of procedures were developed for verifying effects of wood shavings addition to specific mortar properties. Mixes containing wood shavings replacing fine aggregates by 0, 30, 50 and 70% of their volume were made. Workability, fresh mortar unit weight, ultrasonic pulse velocity (UPV) and flexural and compressive strength were determined, based on measurements, at various curing ages. Measurement results and analysis suggest that compressive strength reduction caused by wood shavings addition could be predicted. The outcome was standardized in the form of a multifactorial sigmoidal model. It was also made evident that the mix proportion of cement increases when wood shavings are used as a by volume replacement of conventional fine aggregates, due to the low value of specific gravity of wood compared to conventional aggregates. Another procedure is suggested based on mass and volume measurements aiming at the verification of the mix proportions in the final mortar mixture.

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Properties of Light Weight Concrete Containing Crumb Rubber Subjected to High Temperature

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.718.177 ◽

2016 ◽

Vol 718 ◽

pp. 177-183 ◽

Cited By ~ 1

Author(s):

Tanapan Kantasiri ◽

Pornnapa Kasemsiri ◽

Uraiwan Pongsa ◽

Salim Hiziroglu

Keyword(s):

Compressive Strength ◽

High Temperature ◽

Strength Loss ◽

Crumb Rubber ◽

Unit Weight ◽

Light Weight ◽

Cement Ratio ◽

Light Weight Concrete ◽

Temperature Exposure ◽

Light Weight Aggregate

In this study, the compressive strength, unit weight and chemical structure of light weight concrete (LWC) containing crumb rubber after exposure to high temperature are investigated. The crumb rubber was used as light weight aggregate in place of normal aggregate at the content of 3-15 wt% of LWC. For all mixtures, the water/cement ratio and sand/cement ratio were fixed at 0.5 and 0.2, respectively. The experimental results showed that the unit weight of LWC containing crumb rubber decreased with increasing crumb rubber content. The unit weight and compressive strength values are in range of 1566-1761 kg/m3, 12-29 MPa, respectively. The LWCs containing 3-7 wt% and 15 wt% crumb rubber can meet the requirement of ASTM standards for structural light weight concrete and masonry, respectively. After high temperature exposure, the unit weight loss and compressive strength loss were 25% and 75%, respectively. All specimens still complied with the requirement of ASTM standard for masonry.

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Mechanical Performance of High-Strength Sustainable Concrete under Fire Incorporating Locally Available Volcanic Ash in Central Harrat Rahat, Saudi Arabia

Materials ◽

10.3390/ma14010021 ◽

2020 ◽

Vol 14 (1) ◽

pp. 21

Author(s):

Muhammad Nasir Amin ◽

Kaffayatullah Khan

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Elevated Temperature ◽

Volcanic Ash ◽

Elevated Temperatures ◽

Mechanical Performance ◽

High Strength ◽

Pulse Velocity ◽

Sustainable Concrete ◽

Harrat Rahat

This study investigated the effect of elevated temperatures on the mechanical properties of high-strength sustainable concrete incorporating volcanic ash (VA). For comparison, control and reference concrete specimens with fly ash (FA) were also cast along with additional specimens of VA and FA containing electric arc furnace slag (EAFS). Before thermal exposure, initial tests were performed to evaluate the mechanical properties (compressive strength, tensile strength, and elastic modulus) of cylindrical concrete specimens with aging. Additionally, 91 day moist-cured concrete specimens, after measuring their initial weight and ultrasonic pulse velocity (UPV), were exposed up to 800 °C and cooled to air temperature. Subsequently, the weight loss, residual UPV, and mechanical properties of concrete were measured with respect to exposure temperature. For all concrete specimens, test results demonstrated a higher loss of weight, UPV, and other mechanical properties under exposure to higher elevated temperature. Moreover, all the results of concrete specimens incorporating VA were observed before and after exposure to elevated temperature as either comparable to or slightly better than those of control and reference concrete with FA. According to the experimental results, a correlation was developed between residual UPV and residual compressive strength (RCS), which can be used to assess the RCS of fire-damaged concrete (up to 800 °C) incorporating VA and EAFS.

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Performance Degradation and Microscopic Analysis of Lightweight Aggregate Concrete after Exposure to High Temperature

Materials ◽

10.3390/ma13071566 ◽

2020 ◽

Vol 13 (7) ◽

pp. 1566 ◽

Cited By ~ 2

Author(s):

Weijing Yao ◽

Jianyong Pang ◽

Yushan Liu

Keyword(s):

Compressive Strength ◽

High Temperature ◽

Lightweight Aggregate ◽

Strength Loss ◽

Ultrasonic Pulse Velocity ◽

Ultrasonic Pulse ◽

Pulse Velocity ◽

Lightweight Aggregate Concrete ◽

Aggregate Concrete ◽

Damage Degree

This study analyses the deterioration of mechanical properties in lightweight concrete after exposure to room temperature (20 °C) and high temperature, i.e., up to 1000 °C, including changes in visual appearance, loss of mass, and compressive strength. All-lightweight shale ceramsite aggregate concrete (ALWAC) and semi-lightweight shale ceramsite aggregate concrete (SLWAC) are prepared using an absolute volume method to analyse the relationships between relative ultrasonic pulse velocity, loss rate of compressive strength, damage degree, and temperature levels. Our results show that, under high temperature, the lightweight aggregate ceramsite concrete performs better compared to normal concrete. After exposure to 1000 °C, the ALWAC shows a strength loss of no more than 80%, while the normal concrete loses its bearing capacity, with a similar strength loss as the SLWAC. Furthermore, the relative ultrasonic pulse velocity and damage degree are used to evaluate the effects of high temperature on the concretes, including the voids and cracks on the surface and inside of the specimens, which induces the deterioration of mechanical properties and contributes to the thermal decomposition of the cementing system and the loss of cohesion at the aggregate interface. Based on internal structure analyses, the results from this study confirm that the lightweight aggregate concrete shows a high residual compressive strength after exposure to the high temperature.

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Destructive and non-destructive testing of bronze-waste tire-concrete composites

Challenge Journal of Concrete Research Letters ◽

10.20528/cjcrl.2020.01.002 ◽

2020 ◽

Vol 11 (1) ◽

pp. 11

Author(s):

Tuba Bahtlı ◽

Nesibe Sevde Özbay

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Ultrasonic Pulse Velocity ◽

Ultrasonic Pulse ◽

Test Methods ◽

Pulse Velocity ◽

Destructive Testing ◽

Waste Tire ◽

Schmidt Rebound Hammer ◽

Non Destructive

In this study, the effects of finely-milled bronze and waste tire on the mechanical properties of concrete have been investigated. Approximately 2.5% and 5% by weight for each additive (bronze sawdust and waste tire) were added to dry concrete. The open porosity, density, compressive strength values of cured concrete have been determined. In addition, the Schmidt rebound hammer (SRH) and the ultrasonic pulse velocity (UPV) tests, which are non-destructive test methods, were applied. The microstructure and fracture surfaces of these materials were characterized by scanning electron microscopy (SEM). It was observed that the density of pure concrete was 2.35 g/cm3 while the density was 2.19 g/cm3 for a C+5%B+5%T material. Similarly, pure concrete had an almost three times better compressive strength and a two times better SRH value than those of the C+5%B+5%T material. The density and mechanical properties of concrete materials containing bronze and waste tire decreased due to micro crack formations, weak bonding and deep cracks forming especially between the concrete and additives.

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