scholarly journals Strain-Hardening and High-Ductile Behavior of Alkali-Activated Slag-Based Composites with Added Zirconia Silica Fume

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3523 ◽  
Author(s):  
Jeong-Il Choi ◽  
Se-Eon Park ◽  
Huy Hoàng Nguyễn ◽  
Sang Lyul Cha ◽  
Bang Yeon Lee

This paper presents an experimental study on the effects of zirconia silica fume on the composite properties and cracking patterns of fiber-reinforced alkali-activated slag-based composites. Four mixtures were prepared with added zirconia silica fume and varying water-to-binder ratio. Polyethylene fiber was used as a reinforcing fiber for all the mixtures at a volumetric ratio of 2.0% cubic specimens and uniaxial tensile specimens were prepared to evaluate their density, compressive strength, and tensile behavior. The test results demonstrated that the compressive strength, tensile strength, and tensile strain capacity of the composite can be simultaneously improved by incorporating zirconia silica fume. A mixture incorporating zirconia silica fume showed high-ductile behavior of 26.5% higher tensile strength, and 13.7% higher tensile strain capacity than the mixture without zirconia silica fume. The composite with added zirconia silica fume also showed excellent cracking patterns, i.e., narrow crack spacing and crack width.

2011 ◽  
Vol 368-373 ◽  
pp. 3240-3245
Author(s):  
Zhi Jun Zhou ◽  
Hui Li ◽  
Qiang Song ◽  
Bao Jing Shen

In this paper, water glass was chosen as activator to prepare Alkali-activated slag(AAS) cement. Effects of modulus and dosage of water glass, and admixture (fly ash, slag and silica fume) on the strength of AAS cement was investigated. It was found that the modulus of water glass had great effect on the strength of AAS cement when the mixing amount of water glass was less than 12%. With the incorporation of fly ash or slag, the strength of AAS cement decreased, however the incorporation of silica fume could promote the flexural and compressive strength of AAS cement slightly.


Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 593
Author(s):  
Haining Geng ◽  
Qing Xu ◽  
Saiful B. Duraman ◽  
Qiu Li

Pervious concrete is made of cementitious materials, coarse aggregate, water and additives, with characteristic macro- and meso-connected pore structure, which enables the acceptable mechanical properties and high water permeability for pavement and road applications. In this study, the effect of rheology of fresh alkali-activated slag paste on the sedimentation of paste on the bottom of pervious concrete, meso-structure, connected porosity, mechanical properties and water permeability was investigated by a range of analytical techniques through varying the equivalent alkali content to control the rheology of fresh paste in the pervious concrete. The compressive strength of pervious concrete was related to the percentage area of paste and the average thickness of paste on the surface of coarse aggregate. The tensile strength and water permeability were correlated to the connected porosity of pervious concrete and the rheology of fresh paste. A relative lower fluidity, higher viscosity and shear stress of fresh alkali-activated slag paste favoured lower sedimentation of paste on the bottom of pervious concrete, higher connected porosity, tensile strength and water permeability. There was no correlation between compressive strength and tensile strength of pervious concrete.


2021 ◽  
Vol 5 (10) ◽  
pp. 283
Author(s):  
Jian-Guo Dai ◽  
Bo-Tao Huang ◽  
Surendra P. Shah

This paper summarizes recent advances in strain-hardening ultra-high-performance concretes (UHPC) with synthetic fibers, with emphasis on their tensile properties. The composites described here usually contain about 2.0% high-density polyethylene (PE) fibers. Compared to UHPC with steel fibers, strain-hardening UHPC with synthetic fibers generally show a higher tensile ductility, lower modulus in the cracked state, and relatively lower compressive strength. The tensile strain capacity of strain-hardening UHPC with synthetic fibers increases with increasing tensile strength. The f’cftεt/w index (compressive strength × tensile strength × tensile strain capacity/tensile crack width) is used to compare the overall performance of strain-hardening UHPC. Moreover, a probabilistic approach is applied to model the crack width distributions of strain-hardening UHPC, and estimate the critical tensile strain in practical applications, given a specific crack width limit and cumulative probability. Recent development on strain-hardening UHPC with the use of seawater, sea-sand and PE fibers are also presented.


2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Jeong-Il Choi ◽  
Se-Eon Park ◽  
Su-Tae Kang ◽  
Bang Yeon Lee

Information on the effect of age on the tensile behavior of fiber-reinforced alkali-activated slag-based composite is fairly limited. Therefore, the purpose of this study is to experimentally investigate the effect of age on the compressive strength and tensile properties of the fiber-reinforced alkali-activated slag-based composite. A binder including slag and alkali activators, chemical admixtures, and a reinforcing fiber were selected, and the mixture proportion was determined to make a fiber-reinforced alkali-activated slag-based composite with high ductility. Compressive strength and tensile strength tests were performed, and values were measured at 3, 5, 7, 14, 28, and 90 days. Test results showed that the compressive strength increased as the age increased. Although the first-cracking strength increased like the compressive strength, the increases of tensile strength and tensile strain capacity were not significant compared with those of compressive strength and first-cracking strength.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Mao-chieh Chi ◽  
Jiang-jhy Chang ◽  
Ran Huang

The aim of this study is to investigate the strengths and drying shrinkage of alkali-activated slag paste and mortar. Compressive strength, tensile strength, and drying shrinkage of alkali-activated slag paste and mortar were measured with various liquid/slag ratios, sand/slag ratios, curing ages, and curing temperatures. Experimental results show that the higher compressive strength and tensile strength have been observed in the higher curing temperature. At the age of 56 days, AAS mortars show higher compressive strength than Portland cement mortars and AAS mortars with liquid/slag ratio of 0.54 have the highest tensile strength in all AAS mortars. In addition, AAS pastes of the drying shrinkage are higher than AAS mortars. Meanwhile, higher drying shrinkage was observed in AAS mortars than that observed comparable Portland cement mortars.


2021 ◽  
Vol 13 (4) ◽  
pp. 2407
Author(s):  
Guang-Zhu Zhang ◽  
Xiao-Yong Wang ◽  
Tae-Wan Kim ◽  
Jong-Yeon Lim ◽  
Yi Han

This study shows the effect of different types of internal curing liquid on the properties of alkali-activated slag (AAS) mortar. NaOH solution and deionized water were used as the liquid internal curing agents and zeolite sand was the internal curing agent that replaced the standard sand at 15% and 30%, respectively. Experiments on the mechanical properties, hydration kinetics, autogenous shrinkage (AS), internal temperature, internal relative humidity, surface electrical resistivity, ultrasonic pulse velocity (UPV), and setting time were performed. The conclusions are as follows: (1) the setting times of AAS mortars with internal curing by water were longer than those of internal curing by NaOH solution. (2) NaOH solution more effectively reduces the AS of AAS mortars than water when used as an internal curing liquid. (3) The cumulative heat of the AAS mortar when using water for internal curing is substantially reduced compared to the control group. (4) For the AAS mortars with NaOH solution as an internal curing liquid, compared with the control specimen, the compressive strength results are increased. However, a decrease in compressive strength values occurs when water is used as an internal curing liquid in the AAS mortar. (5) The UPV decreases as the content of zeolite sand that replaces the standard sand increases. (6) When internal curing is carried out with water as the internal curing liquid, the surface resistivity values of the AAS mortar are higher than when the alkali solution is used as the internal curing liquid. To sum up, both NaOH and deionized water are effective as internal curing liquids, but the NaOH solution shows a better performance in terms of reducing shrinkage and improving mechanical properties than deionized water.


2011 ◽  
Vol 287-290 ◽  
pp. 1237-1240
Author(s):  
Lan Fang Zhang ◽  
Rui Yan Wang

The aim of this paper is to study the influence of lithium-slag and fly ash on the workability , setting time and compressive strength of alkali-activated slag concrete. The results indicate that lithium-slag and fly-ash can ameliorate the workability, setting time and improve the compressive strength of alkali-activated slag concrete,and when 40% or 60% slag was replaced by lithium-slag or fly-ash, above 10 percent increase in 28-day compressive strength of concrete were obtained.


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