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The porous lightweight aggregates adversely affect fresh properties of concrete, including slump and disruption of pumping concrete. Besides, this type of concrete is very susceptible to shrinkage cracking. In this study, two types of lightweight aggregates were used with a combination of two types of coating, including hydrophobic polymers ‐polyvinyl acetate and styrene‐butadiene rubber coatings. The coatings were applied in single and double layers. For the fresh concrete, the fresh properties of concrete, including slump flow, T50, flow time, and L‐Box were evaluated and for the hardened concrete, compressive strength, flexural strength, tensile strength, water absorption and shrinkage was studied. It was seen that the slump flow of coated lightweight aggregates increased by 10%, and also coating process reduced the water absorption of the aggregates up to 82%. The compressive strength increased by up to 21% for the coated aggregates. Scanning electron microscopy was also used to investigate the microstructure of the mortar‐aggregate interface. Microstructural images showed a uniform and dense interfacial zone of cementitious matrix‐aggregate for coated lightweight aggregates. Moreover, an improvement of 50–150 μm in the interfacial zone's thickness was seen for coated aggregates compared to uncoated aggregates.
Mir Yashar Vahabi; Behzad Tahmouresi; Hossein Mosavi; Siavash Fakhretaha Aval. Effect of pre‐coating lightweight aggregates on the self‐compacting concrete. Structural Concrete 2021, 1 .
AMA StyleMir Yashar Vahabi, Behzad Tahmouresi, Hossein Mosavi, Siavash Fakhretaha Aval. Effect of pre‐coating lightweight aggregates on the self‐compacting concrete. Structural Concrete. 2021; ():1.
Chicago/Turabian StyleMir Yashar Vahabi; Behzad Tahmouresi; Hossein Mosavi; Siavash Fakhretaha Aval. 2021. "Effect of pre‐coating lightweight aggregates on the self‐compacting concrete." Structural Concrete , no. : 1.
The use of industrial plant wastes such as fly ash (FA) and cement kiln dust (CKD) is an optimal solution to improve some of the fresh and hardened properties of concrete and also a rational choice to reduce the effect of carbon dioxide in the construction industry. In this study, different amounts of CKD (0–40%), as a waste material, and FA (0–30%) as a pozzolanic material, were used as a single and hybrid replacement of cement. Then, Taguchi method with two parameters of water to binder ratios and cement replacement ratio was used to determine the optimal mixing designs before construction from environmental and economic points of view. Comparison of the Taguchi method and experimental results for selecting the most favorable mixture designs showed that Taguchi method exhibited suitable choices in the range of optimal experimental results with regard to the initial parameters. This means that if the water-to-cement, CKD-to-cement, and the fly ash-to-cement ratios were 0.45, 9%, and 14%, respectively, it would be possible to obtain the best possible values for the strength to price, CO2 emission factor, and the standard deviation ratio.
Seyedeh Marjan Bagheri; Mahdi Koushkbaghi; Ehsan Mohseni; Shahnaz Koushkbaghi; Behzad Tahmouresi. Evaluation of environment and economy viable recycling cement kiln dust for use in green concrete. Journal of Building Engineering 2020, 32, 101809 .
AMA StyleSeyedeh Marjan Bagheri, Mahdi Koushkbaghi, Ehsan Mohseni, Shahnaz Koushkbaghi, Behzad Tahmouresi. Evaluation of environment and economy viable recycling cement kiln dust for use in green concrete. Journal of Building Engineering. 2020; 32 ():101809.
Chicago/Turabian StyleSeyedeh Marjan Bagheri; Mahdi Koushkbaghi; Ehsan Mohseni; Shahnaz Koushkbaghi; Behzad Tahmouresi. 2020. "Evaluation of environment and economy viable recycling cement kiln dust for use in green concrete." Journal of Building Engineering 32, no. : 101809.
Construction of new structures, including concrete thin-walled shell structures, using high technology and economic efficiency has been become inevitable due to the advancement and development of concrete industry. Thin-walled shell structures are appropriate elements to construct large installation infrastructures such as oil and water reservoirs and silos. When cylindrical shells are under internal pressure, hoop or tangential stress and strain are generated in the walls, and evaluation of these elements is the purpose of the present research. In this study, hoop stress-strain of fiber-reinforced cementitious composite thin-walled cylindrical shells under uniform internal hydrostatic loading has been evaluated. For this purpose, 36 small models of thin-walled cylindrical shells containing 0, 5, and 10% silica fume (SF) and 0, 0.5, 1, 1.5, 2, and 2.5% glass fiber were made and tested after 28 days of wet-curing conditions. The compressive and flexural strengths of composite samples were tested to relate concrete strengths with the results of cylindrical shells. The results showed that the use of silica fume increased compressive and flexural strengths up to 27 and 32%, respectively. Also, the presence of fibers had no significant effect on the compressive strength, but increased the flexural strength up to 21%. In cylindrical shells, the addition of silica fume increased the hoop tensile strength up to 10% and decreased the hoop tensile strain to 28%. Furthermore, the addition of 2.5 and 0.5% glass fibers raised hoop ultimate strain 7.4 times and hoop tensile strength up to 37%, respectively.
Hosein Ghasemzadeh Mosavinejad; Ashkan Saradar; Behzad Tahmouresi. Hoop Stress-Strain in Fiber-Reinforced Cementitious Composite Thin-Walled Cylindrical Shells. Journal of Materials in Civil Engineering 2018, 30, 04018258 .
AMA StyleHosein Ghasemzadeh Mosavinejad, Ashkan Saradar, Behzad Tahmouresi. Hoop Stress-Strain in Fiber-Reinforced Cementitious Composite Thin-Walled Cylindrical Shells. Journal of Materials in Civil Engineering. 2018; 30 (10):04018258.
Chicago/Turabian StyleHosein Ghasemzadeh Mosavinejad; Ashkan Saradar; Behzad Tahmouresi. 2018. "Hoop Stress-Strain in Fiber-Reinforced Cementitious Composite Thin-Walled Cylindrical Shells." Journal of Materials in Civil Engineering 30, no. 10: 04018258.
Concrete shrinkage and volume reduction happens due to the loss of moisture, which eventually results in cracks and more concrete deformation. In this study, the effect of polypropylene (PP), steel, glass, basalt, and polyolefin fibers on compressive and flexural strength, drying shrinkage, and cracking potential, using the ring test at early ages of high-strength concrete mixtures, was investigated. The restrained shrinkage test was performed on concrete ring specimens according to the ASTM C1581 standard. The crack width and age of restrained shrinkage cracking were the main parameters studied in this research. The results indicated that the addition of fiber increases the compressive strength by 16%, 20%, and 3% at the age of 3, 7, and 28 days, respectively, and increases the flexural toughness index up to 7.7 times. Steel and glass fibers had a better performance in flexural strength, but relatively poor action in the velocity reduction and cracking time of the restrained shrinkage. Additionally, cracks in all concrete ring specimens except for the polypropylene-containing mixture, was developed to a full depth crack. The mixture with polypropylene fiber indicated a reduction in crack width up to 62% and an increasing age cracking up to 84%.
Ashkan Saradar; Behzad Tahmouresi; Ehsan Mohseni; Ali Shadmani. Restrained Shrinkage Cracking of Fiber-Reinforced High-Strength Concrete. Fibers 2018, 6, 12 .
AMA StyleAshkan Saradar, Behzad Tahmouresi, Ehsan Mohseni, Ali Shadmani. Restrained Shrinkage Cracking of Fiber-Reinforced High-Strength Concrete. Fibers. 2018; 6 (1):12.
Chicago/Turabian StyleAshkan Saradar; Behzad Tahmouresi; Ehsan Mohseni; Ali Shadmani. 2018. "Restrained Shrinkage Cracking of Fiber-Reinforced High-Strength Concrete." Fibers 6, no. 1: 12.
Ali Sadrmomtazi; Behzad Tahmouresi; Ashkan Saradar. Effects of silica fume on mechanical strength and microstructure of basalt fiber reinforced cementitious composites (BFRCC). Construction and Building Materials 2018, 162, 321 -333.
AMA StyleAli Sadrmomtazi, Behzad Tahmouresi, Ashkan Saradar. Effects of silica fume on mechanical strength and microstructure of basalt fiber reinforced cementitious composites (BFRCC). Construction and Building Materials. 2018; 162 ():321-333.
Chicago/Turabian StyleAli Sadrmomtazi; Behzad Tahmouresi; Ashkan Saradar. 2018. "Effects of silica fume on mechanical strength and microstructure of basalt fiber reinforced cementitious composites (BFRCC)." Construction and Building Materials 162, no. : 321-333.
Nowadays pozzolans are used vastly in civil projects. Pozzolan is a natural or artificial material containing active silica that increase the strength and improves some properties of concrete. In this survey for investigating some important properties of concrete, silica fume and fly ash was used in replacement of cement in different weights. Concrete compositions were made with water-cement ratio of 0.45 and cured under the same conditions. The main focus of this survey is to investigate the individual and combined effect of using Pozzolan on mechanical properties, permeability and shrinkage of concrete. The mechanical properties of concrete in compressive and bending strength at the age of 7, 28 and 90 days, were evaluated. Permeability was investigated with the water absorption test. The drying shrinkage of concrete was monitored for 90 days. Scanning Electron Microscopy (SEM) images was used in concrete cement based matrix morphology. The results showed that the addition of pozzolan increases the mechanical strength and reduce permeability and increase the drying shrinkage in some mixtures.
Ali Sadr Momtazi; Behzad Tahmouresi; Reza Kohani Khoshkbijari. An Investigation on Mechanical Properties and Durability of Concrete Containing Silica Fume and Fly Ash. Civil Engineering Journal 2016, 2, 189 -196.
AMA StyleAli Sadr Momtazi, Behzad Tahmouresi, Reza Kohani Khoshkbijari. An Investigation on Mechanical Properties and Durability of Concrete Containing Silica Fume and Fly Ash. Civil Engineering Journal. 2016; 2 (5):189-196.
Chicago/Turabian StyleAli Sadr Momtazi; Behzad Tahmouresi; Reza Kohani Khoshkbijari. 2016. "An Investigation on Mechanical Properties and Durability of Concrete Containing Silica Fume and Fly Ash." Civil Engineering Journal 2, no. 5: 189-196.