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Effect of Harsh Environments on the Mechanical Properties and Durability of Fly Ash-Based Geopolymer Concretes
, M.Sc. Thesis Sharif University of Technology ; Ghaemian, Mohsen (Supervisor) ; Toufigh, Vahab (Supervisor)
Abstract
In the present study, the performance of fly ash-based geopolymer concrete blended with cement as an additional calcium source under exposure to marine, acidic and alkaline environments was evaluated. Three mixtures of fly ash-based geopolymer concrete with different cement ratios (0, 10 & 20%) were prepared and immersed in tap water, seawater, sulfuric acid, and sodium hydroxide solutions for up to one year. Change in the appearance, weight, compressive strength, splitting tensile strength, energy absorption and microstructure of the specimens were evaluated at 1, 3, 6, 9 and 12 months of exposure. Ultrasonic pulse velocity test was also used to determine its relationship with the...
Experimental Investigation of Fracture Behavior and Mechanical Characteristics of Rammed Earth Materials
, M.Sc. Thesis Sharif University of Technology ; Toufigh, Vahab (Supervisor)
Abstract
Rammed earth (RE) structures are getting popular due to sustainability, environmental-friendly and economic advantages. Various studies have investigated the mechanical behavior and the energy performance of RE materials. However, little is known about the fracture behavior of RE materials. In this research, the fracture properties of RE materials containing different percentages of various stabilizers were investigated using a modified wedge splitting test. The stabilizers were cement, pozzolan, microsilica, glass-fiber, guar-gum and phase change material. In addition, the effect of stabilizers on the microstructure and the phase composition was inspected using scanning electron microscope...
Evaluation of Mechanical Properties of Rammed Earth Exposed to High Temperature and Flame with Destructive and Non-Destructive Tests
, M.Sc. Thesis Sharif University of Technology ; Toufigh, Vahab (Supervisor)
Abstract
The environmental friendliness and sustainable development of rammed earth structures has attracted the attention of numerous researchers in recent years. Obviously, a better understanding of the structural and mechanical performance of rammed earth is the way to use rammed earth as a sustainable building material. Structural fire safety is one of the primary considerations in the design of structures. Several experiments and investigations had been conducted to investigate the behavior of materials at high temperatures. Base on author knowledge at present, few studies are available on thermomechanical properties of earthen construction materials at temperatures higher than 100°C and even...
Influence of different types of nano-SiO2 particles on properties of high-performance concrete
, Article Construction and Building Materials ; Volume 113 , 2016 , Pages 188-201 ; 09500618 (ISSN) ; Mobini, M. H ; Hosseini, P ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
The aim of this study was to evaluate the effects of applying low replacement ratios (0.75% and 1.50% of the binder weight) of nano-SiO2 particles with different specific surface areas (200 and 380 m2/g) on the properties of high-performance concrete (HPC). Mechanical (compressive and splitting tensile strengths), electrical resistivity, non-destructive (ultrasonic pulse velocity), and microstructural (mercury intrusion porosimetry, X-ray diffraction, and scanning electron microscopy) tests were conducted to investigate the macroscopic and microscopic effects of nano-SiO2 particles on HPC characteristics. The results indicated that the performance of nano-SiO2 particles significantly...
Optimizing the mixture design of polymer concrete: An experimental investigation
, Article Construction and Building Materials ; Volume 167 , 2018 , Pages 185-196 ; 09500618 (ISSN) ; Tabatabaeian, M ; Joshaghani, A ; Ozbakkaloglu, T ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Over the last few decades, polymer concrete (PC) has been finding use in quick repairing of concrete structures. However, there have been only few studies on the mechanical behavior of PC. The aim of this study is to evaluate the mechanical behavior of PC using destructive and non-destructive tests (NDT). The mixtures were prepared with three different polymer ratios (10%, 12%, and 14%) and two different coarse aggregate sizes (4.75–9.5 mm and 9.5–19 mm). The samples were subsequently tested under three different temperatures (−15 °C, +25 °C, and +65 °C). The Taguchi method and analysis of variance (ANOVA) were used to optimize PC mixes based on the compressive, splitting-tensile, and...
Properties of concrete containing Guar gum
, Article European Journal of Environmental and Civil Engineering ; 2020 ; Toufigh, V ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
This study explores the effect of Guar gum as an eco-friendly additive on concrete mechanical characteristics. In the first stage, the slump and relative humidity tests were carried out for the fresh mortar, and tensile and compressive strengths were then determined for fifteen different mixture designs with two different curing times. Further, an exponential correlation was obtained between the ultrasonic pulse velocity and the compression test results. Additionally, scanning electron microscope (SEM) was employed to assess the bond between aggregates and Guar gum. At last, the Taguchi method and ANOVA were utilized to conduct the optimum states of the mechanical characteristics of the...
Properties of concrete containing Guar gum
, Article European Journal of Environmental and Civil Engineering ; Volume 26, Issue 7 , 2022 , Pages 2736-2752 ; 19648189 (ISSN) ; Toufigh, V ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
This study explores the effect of Guar gum as an eco-friendly additive on concrete mechanical characteristics. In the first stage, the slump and relative humidity tests were carried out for the fresh mortar, and tensile and compressive strengths were then determined for fifteen different mixture designs with two different curing times. Further, an exponential correlation was obtained between the ultrasonic pulse velocity and the compression test results. Additionally, scanning electron microscope (SEM) was employed to assess the bond between aggregates and Guar gum. At last, the Taguchi method and ANOVA were utilized to conduct the optimum states of the mechanical characteristics of the...
Experimental and analytical evaluation of rubberized polymer concrete
, Article Construction and Building Materials ; Volume 155 , 2017 , Pages 495-510 ; 09500618 (ISSN) ; Toufigh, V ; Sharif University of Technology
Abstract
Polymer concrete (PC) has been widely used for quick repairing of concrete pavement and structures in recent years. This paper studies the mechanical behavior of the rubberized polymer concrete. Crumb and chipped rubber were used to replace fine and coarse aggregates in PC, respectively. A complete series of destructive tests including impact test, compression and splitting tensile tests and non-destructive methods including ultrasonic test, digital signal processing, electrical conductivity, and microstructure analysis was performed to demonstrate the various potential applications of the rubberized PC. X-ray diffraction (XRD) also provided information regarding the chemical composition and...