Using calcium‐rich precursors to improve the early‐compressive strength of alkali‐activated slag cement at low temperature

Properties of alkali-activated slag cements compounded with soluble glasse with a high silicate modulus Ms=2.6 were detailedly studied in this paper, including compressive strength and flexure strength characterictics at the ages of 3,7,28 days and flow values of fresh cement mixtures on a jolting table. As a result, with the compressive strength at the age of 28 days of 95.6-107.8 MPa has been developed, and the flow values and strength characteristics of alkali-activated slag cement mortars increased with increase in a water to cement (alkaline activator solution to slag) ratio, and the flow value (determined on the cement mortar mixtures) would reach 145 mm. Moreover, the development speed of strength characteristics of mortar specimens would be affected negatively by increasing of water demand (requirement).

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Effect of Cr6+ on the Properties of Alkali-Activated Slag Cement

Frontiers in Materials ◽

10.3389/fmats.2021.754463 ◽

2021 ◽

Vol 8 ◽

Author(s):

Fu Bo ◽

Cheng Zhenyun

Keyword(s):

Compressive Strength ◽

Setting Time ◽

Cement Stone ◽

Slag Cement ◽

Hydration Kinetics ◽

Alkali Activated Slag ◽

Dual Beam ◽

Press Method ◽

Activated Slag ◽

Alkali Activated

In order to investigate the effect of Cr6+ on the properties of alkali-activated slag cement (AAS), the effects of added dosage of Na2Cr2O4 on the setting time and compressive strength of AAS were measured. The leaching concentration of Cr6+ from AAS cement stone was measured using dual-beam UV-visible spectrophotometry. The effect of Na2Cr2O4 on the hydration kinetics of AAS cement was monitored by microcalorimetry and the corresponding kinetic parameters were analyzed. The pore solution from AAS was collected and analyzed using the high pressure press method. The effects of Na2Cr2O4 on the hydration products of AAS cement were observed and compared using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The experimental results showed that the AAS hydration process was markedly affected by Na2Cr2O4 dosage. The setting time of AAS pastes was increased and the compressive strength of cement stones was reduced with increasing dosage of Na2Cr2O4. With the development of AAS hydration, the leaching concentration of Na2Cr2O4 gradually decreased. Na2Cr2O4 did not affect the dissolution of slag particles, but impeded the formation of C-S-H gel. The Cr6+ was immobilized chemically in the form of needle-like CaCrO4 particles formed by the chemical reaction between Na2Cr2O4 and Ca2+ leaching from the slag.

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Factors Influencing the Strength of Alkali-Activated Slag Cement

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.368-373.3240 ◽

2011 ◽

Vol 368-373 ◽

pp. 3240-3245

Author(s):

Zhi Jun Zhou ◽

Hui Li ◽

Qiang Song ◽

Bao Jing Shen

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Silica Fume ◽

Water Glass ◽

Slag Cement ◽

Alkali Activated Slag ◽

Factors Influencing ◽

Activated Slag ◽

Alkali Activated

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.

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Effect of Dosage and Modulus of Water Glass on AC Impedance Properties of Alkali-Activated Slag Cement Mortar

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.423-426.1018 ◽

2013 ◽

Vol 423-426 ◽

pp. 1018-1026

Author(s):

Fu Qiang He ◽

Xiao Peng An

Keyword(s):

Compressive Strength ◽

Water Glass ◽

Cement Mortar ◽

Ac Impedance ◽

Slag Cement ◽

Bulk Resistance ◽

Alkali Activated Slag ◽

Activated Slag ◽

Alkali Activated

Compressive strength and AC impedance of mortar made with water-glass-activated slag were investigated as a dependence of modulus (0.5-2.0) and dosage (2-6%) of the water-glass. Results shown that when the dosage of water glass is 2- 4 %, the modulus of the water glass has a little effect on the compressive strength. In the case of the dosage of water glass is beyond 4 %, when modulus of the water glass change from 0.5-1.0, the compressive strength obviously increases with increase of modulus of water glass and when modulus of the water glass change from 1.0-2.0, the modulus of the water glass has a little effect on the compressive strength. The strength increases with increase of the dosage from 2 to 6%. In the case same dosage and modulus, there is a rather good power correlation between the bulk resistance and the activated age. With increase of the dosage, the bulk resistance significantly decreases when the dosage is below 4%. The decreasing degree is small when the dosage is beyond 4%. The decreasing degree derived from the dosage increases with the activated age. The effect of the modulus on the bulk resistance depends on range of the dosage. However, it can be regarded that when the dosage is 4% and 6%, the modulus has small effect on the bulk resistance in the case of all the dosages.

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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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Influence of hydrated lime on mechanical and shrinkage properties of alkali-activated slag cement

Construction and Building Materials ◽

10.1016/j.conbuildmat.2021.123201 ◽

2021 ◽

Vol 289 ◽

pp. 123201

Author(s):

Juan He ◽

Wenbin Bai ◽

Weihao Zheng ◽

Junhong He ◽

Guochen Sang

Keyword(s):

Hydrated Lime ◽

Slag Cement ◽

Alkali Activated Slag ◽

Activated Slag ◽

Alkali Activated

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Research on iron ore tailing improving Compressive Strength of Alkali-activated Slag Foamed concrete

Proceedings of the 5th International Conference on Civil Engineering and Transportation 2015 ◽

10.2991/iccet-15.2015.256 ◽

2015 ◽

Author(s):

Junzhe Li ◽

Yuze Tian ◽

Qiubai Sun ◽

Changsheng Pan

Keyword(s):

Compressive Strength ◽

Iron Ore ◽

Alkali Activated Slag ◽

Foamed Concrete ◽

Iron Ore Tailing ◽

Activated Slag ◽

Alkali Activated

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Uptake of chloride and carbonate by Mg-Al and Ca-Al layered double hydroxides in simulated pore solutions of alkali-activated slag cement

Cement and Concrete Research ◽

10.1016/j.cemconres.2017.05.015 ◽

2017 ◽

Vol 100 ◽

pp. 1-13 ◽

Cited By ~ 79

Author(s):

Xinyuan Ke ◽

Susan A. Bernal ◽

John L. Provis

Keyword(s):

Layered Double Hydroxides ◽

Slag Cement ◽

Alkali Activated Slag ◽

Activated Slag ◽

Double Hydroxides ◽

Alkali Activated

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Experimental Study on Alkali-Activated Slag-Lithium Slag-Fly Ash Environmental Concrete

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.287-290.1237 ◽

2011 ◽

Vol 287-290 ◽

pp. 1237-1240

Author(s):

Lan Fang Zhang ◽

Rui Yan Wang

Keyword(s):

Experimental Study ◽

Compressive Strength ◽

Fly Ash ◽

Setting Time ◽

Alkali Activated Slag ◽

Percent Increase ◽

Compressive Strength Of Concrete ◽

Activated Slag ◽

Lithium Slag ◽

Alkali Activated

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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