Effect of Rheology of Fresh Paste on the Pore Structure and Properties of Pervious Concrete Based on the High Fluidity Alkali-Activated Slag

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.

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The Effect of Different Types of Internal Curing Liquid on the Properties of Alkali-Activated Slag (AAS) Mortar

Sustainability ◽

10.3390/su13042407 ◽

2021 ◽

Vol 13 (4) ◽

pp. 2407

Author(s):

Guang-Zhu Zhang ◽

Xiao-Yong Wang ◽

Tae-Wan Kim ◽

Jong-Yeon Lim ◽

Yi Han

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Deionized Water ◽

Internal Curing ◽

Control Group ◽

Alkali Activated Slag ◽

Different Types ◽

Naoh Solution ◽

Activated Slag ◽

Alkali Activated

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.

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A closed-form fracture model to predict tensile strength and fracture toughness of alkali-activated slag and fly ash blended concrete made by sea sand and recycled coarse aggregate

Construction and Building Materials ◽

10.1016/j.conbuildmat.2021.123976 ◽

2021 ◽

Vol 300 ◽

pp. 123976

Author(s):

Shutong Yang ◽

Linzhen Li ◽

Zhongke Sun ◽

Junhao Wang ◽

Qianhui Guo ◽

...

Keyword(s):

Fracture Toughness ◽

Tensile Strength ◽

Fly Ash ◽

Closed Form ◽

Coarse Aggregate ◽

Alkali Activated Slag ◽

Recycled Coarse Aggregate ◽

Sea Sand ◽

Activated Slag ◽

Alkali Activated

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Effect of Sodium Aluminate Dosage as a Solid Alkaline Activator on the Properties of Alkali-Activated Slag Paste

Advances in Materials Science and Engineering ◽

10.1155/2021/6658588 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Bin Chen ◽

Jun Wang ◽

Jinyou Zhao

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Setting Time ◽

Sodium Aluminate ◽

Hydration Reaction ◽

Hydration Products ◽

Alkali Activated Slag ◽

Alkaline Activator ◽

Activated Slag ◽

Alkali Activated

Extensive research into alkali-activated slag as a green gel material to substitute for cement has been done because of the advantages of low-carbon dioxide emissions and recycling of industrial solid waste. Alkali-activated slag usually has good mechanical properties, but the too fast setting time restricted its application and promotion. Changing the composition of alkaline activator could optimize setting time, usually making it by adding sodium carbonate or sodium sulfate but this would cause insufficient hydration reaction power and hinder compressive strength growth. In this paper, the effect of sodium aluminate dosage as an alkaline activator on the setting time, fluidity, compressive strength, hydration products, and microstructures was studied through experiments. It is fair to say that an appropriate amount of sodium aluminate could obtain a suitable setting time and better compressive strength. Sodium aluminate provided enough hydroxyl ions for the paste to promote the hydration reaction process that ensured obtaining high compressive strength and soluble aluminium formed precipitate wrapped on the surface of slag to inhibit the hydration reaction process in the early phase that prolonged setting time. The hydration mechanism research found that sodium aluminate played a key role in the formation of higher cross-linked gel hydration products in the late phase of the process. Preparing an alkali-activated slag with excellent mechanical properties and suitable setting time will significantly contribute to its application and promotion.

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Effect of Polymer Admixtures on Mechanical Properties of Alkali-Activated Slag Mortars

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1124.145 ◽

2015 ◽

Vol 1124 ◽

pp. 145-150 ◽

Cited By ~ 1

Author(s):

Olesia Mikhailova ◽

Pavel Rovnaník

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Polyethylene Glycol ◽

Acrylic Acid ◽

Polypropylene Glycol ◽

Alkali Activated Slag ◽

Different Types ◽

Methyl Metacrylate ◽

Activated Slag ◽

Alkali Activated

Alkali-activated slag (AAS) binders have lower environmental impact due to its production process, but also have disadvantages as an increased shrinkage followed by formation of microcracks. The effect of polymer admixtures based on vinyl acetate, ethylene and acrylic acid ester, methyl metacrylate and different types of polyethylene glycol (PEG) and polypropylene glycol (PPG) on properties of alkali-activated slag concrete was studied. Admixtures used for mortars were tested to improve shrinkage, workability and compressive strength, flexural strength. The analysis also showed the effect of the admixtures on microstructure of the alkali-activated slag pastes and mortars.

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Effects of Aging on the Tensile Properties of Polyethylene Fiber-Reinforced Alkali-Activated Slag-Based Composite

Advances in Materials Science and Engineering ◽

10.1155/2019/7573635 ◽

2019 ◽

Vol 2019 ◽

pp. 1-8 ◽

Cited By ~ 3

Author(s):

Jeong-Il Choi ◽

Se-Eon Park ◽

Su-Tae Kang ◽

Bang Yeon Lee

Keyword(s):

Tensile Strength ◽

Compressive Strength ◽

Tensile Properties ◽

Fiber Reinforced ◽

Alkali Activated Slag ◽

Polyethylene Fiber ◽

Activated Slag ◽

Effects Of Aging ◽

Effect Of Age ◽

Alkali Activated

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.

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A Systematic Study on Polymer-Modified Alkali-Activated Slag–Part II: From Hydration to Mechanical Properties

Materials ◽

10.3390/ma13153418 ◽

2020 ◽

Vol 13 (15) ◽

pp. 3418 ◽

Cited By ~ 1

Author(s):

Zichen Lu ◽

Jan-Philip Merkl ◽

Maxim Pulkin ◽

Rafia Firdous ◽

Steffen Wache ◽

...

Keyword(s):

Mechanical Properties ◽

Pore Structure ◽

Analytical Techniques ◽

Hydration Products ◽

Ion Diffusion ◽

X Ray Diffraction ◽

Alkali Activated Slag ◽

Activated Slag ◽

Alkali Activated ◽

Polymer Latex

The effect of styrene-acrylate (SA) polymer latex on alkali-activated slag (AAS) was systematically studied in the aspects of hydration, hydration products, pore structure and mechanical properties through the combined analytical techniques including calorimetry, X-ray diffraction, thermogravimetric analysis, mercury intrusion porosimetry, and mechanical measurement. It was found that the addition of SA does not retard the AAS hydration, but slightly accelerates it, possibly due to the increasing ion diffusion through the loosely structured hydration products. Pore structure analysis indicates that the addition of polymer increases the cumulative pore volume and the portion of pores with size >100 nm in the hardened AAS paste. The addition of SA latex results in a continuous decrease of the compressive strength, but the flexural strength firstly increases and then decreases with the increase of polymer dosage. The polymer dosage of 2.5 wt % is optimal when applying polymer latex in the AAS system in this study.

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

Materials ◽

10.3390/ma12213523 ◽

2019 ◽

Vol 12 (21) ◽

pp. 3523 ◽

Cited By ~ 1

Author(s):

Jeong-Il Choi ◽

Se-Eon Park ◽

Huy Hoàng Nguyễn ◽

Sang Lyul Cha ◽

Bang Yeon Lee

Keyword(s):

Tensile Strength ◽

Compressive Strength ◽

Silica Fume ◽

Tensile Strain ◽

Alkali Activated Slag ◽

Strain Capacity ◽

Activated Slag ◽

Ductile Behavior ◽

Tensile Strain Capacity ◽

Alkali Activated

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.

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Strength and Drying Shrinkage of Alkali-Activated Slag Paste and Mortar

Advances in Civil Engineering ◽

10.1155/2012/579732 ◽

2012 ◽

Vol 2012 ◽

pp. 1-7 ◽

Cited By ~ 34

Author(s):

Mao-chieh Chi ◽

Jiang-jhy Chang ◽

Ran Huang

Keyword(s):

Tensile Strength ◽

Compressive Strength ◽

Portland Cement ◽

Liquid Slag ◽

Drying Shrinkage ◽

Curing Temperature ◽

Alkali Activated Slag ◽

Cement Mortars ◽

Activated Slag ◽

Alkali Activated

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.

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