scholarly journals Effect of Carbonation on Abrasion Resistance of Alkali-Activated Slag with Various Activators

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2812 ◽  
Author(s):  
Hyeong-Ki Kim ◽  
Keum-Il Song ◽  
Jin-Kyu Song ◽  
Jeong Gook Jang
Keyword(s):  
Compressive Strength ◽  
Abrasion Resistance ◽  
Test Method ◽  
Test Results ◽  
Alkali Activated Slag ◽  
Matrix Strength ◽  
Before And After ◽  
Activated Slag ◽  
The Relationship ◽  
Alkali Activated

The effect of carbonation on the abrasion resistance of alkali-activated slag (AAS) was investigated. Various activator sets were selected for synthesizing AAS specimens, and the compressive strength was measured before and after carbonation. The abrasion resistance of the specimens was measured in accordance with the ASTM C944 test method. The relationship between the mass loss caused by abrasion and compressive strength was analyzed to understand the effect of matrix strength on abrasion resistance. Test results showed that the decrease in compressive strength of AAS specimens by carbonation reduced their abrasion resistance. In addition, the abrasion resistance of AAS before and after carbonation was sensitively influenced by activator type. It can be concluded that additional caution is required when using AAS where abrasion may have occurred.

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

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.

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

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.

A Review of Alkali-Activated Slag as Cement Replacement

2019 ◽  
Vol 803 ◽  
pp. 262-266
Author(s):  
Osama Ahmed Mohamed ◽  
Maadoum M. Mustafa
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Construction Industry ◽  
Ordinary Portland Cement ◽  
Environmental Footprint ◽  
Alkali Activated Slag ◽  
Cement Replacement ◽  
Activated Slag ◽  
Alkali Activated

Alkali activated slag (AAS) offers opportunities to the construction industry as an alternative to ordinary Portland cement (OPC). The production of OPC and its use contributes significantly to release of CO2 into the atmosphere while AAS is an industrial by-product that contributes much less to the environmental footprint that needs to be recycled if not landfilled. This paper outlines some of the key properties, merits and demerits of AAS when used as alternative to OPC. Competitive compressive strength of AAS concrete is amongst of the advantages of replacing cement with AAS while high shrinkage and carbonation levels are potential disadvantages.

Properties of Alkli-Activated Slag Cement Compounded with Soluble Glasses with a High Silicate Modulus

2013 ◽  
Vol 712-715 ◽  
pp. 905-908
Author(s):  
Qun Pan ◽  
Bin Zhu ◽  
Xiao Huang ◽  
Lin Liu
Keyword(s):  
Compressive Strength ◽  
Cement Mortar ◽  
Strength Characteristics ◽  
Slag Cement ◽  
Alkali Activated Slag ◽  
Cement Mortars ◽  
Alkaline Activator ◽  
Activated Slag ◽  
Alkali Activated ◽  
High Silicate

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).

scholarly journals Alteration in Molecular Structure of Alkali Activated Slag with Various Water To Binder Ratios Under Accelerated Carbonation

2021 ◽  
Author(s):  
Thi Nhan Nguyen ◽  
Quoc Phung ◽  
Ziyou Yu ◽  
Lander Frederickx ◽  
Diederik Jacques ◽  
...  
Keyword(s):  
Sodium Carbonate ◽  
Cementitious Materials ◽  
Mas Nmr ◽  
Accelerated Carbonation ◽  
Alkali Activated Slag ◽  
Before And After ◽  
Activated Slag ◽  
A Charge ◽  
A Minor ◽  
Alkali Activated

Abstract Carbonation of alkali activated materials is one of the main deteriorations affecting their durability. However, current understanding in structural alteration of these materials exposed to an environment inducing carbonation at nano/micro scale remains limited. This study examined the evolution of phase assemblages of alkali activated slag mortars subjected to accelerated carbonation (1% CO2, 60% relative humidity, up to 28 day carbonation) using XRD, FTIR and 29Si, 27Al, 23Na MAS NMR. Samples with three water to binder (w/b) ratios (0.35, 0.45, and 0.55) were investigated. The results show that the phase assemblages mainly consisted of C-A-S-H, disordered remnant aluminosilicate binder, and a minor hydrotalcite as a secondary product. Upon carbonation, calcium carbonate is mainly formed as the vaterite polymorph, while no sodium carbonate is found after carbonation as commonly reported. The sodium acts primarily as a charge balancing ion without producing sodium carbonate as a final carbonation product in 28-day carbonated materials. The C-A-S-H structure becomes more cross-linked due to the decalcification of this phase evidenced by the appearance of Q4 groups, which replace the Q1 and Q2 ones as observed in the 29Si MAS NMR spectra, and the dominance of Al (IV) in 27Al MAS NMR. Especially, unlike cementitious materials, the influence of w/b ratio on the crystalline phase formation and structure of C-A-S-H in the alkali activated mortars before and after carbonation is limited.

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