scholarly journals Compressive Strength Characteristics of Cemented Tailings Backfill with Alkali-Activated Slag

2018 ◽  
Vol 8 (9) ◽  
pp. 1537 ◽  
Author(s):  
Gaili Xue ◽  
Erol Yilmaz ◽  
Weidong Song ◽  
Shuai Cao
Keyword(s):  
Compressive Strength ◽  
Mine Tailings ◽  
Low Cost ◽  
Cementitious Materials ◽  
Cementitious Material ◽  
Solid Wastes ◽  
Fine Grained ◽  
Activated Slag ◽  
The Relationship ◽  
Alkali Activated

With the use of glauberite mineral (GM) and sodium hydroxide (SH) alkaline catalysts to stimulate slag powder’s internal cementation activity and incorporate the two fine-grained solid wastes, such as quicklime (Q) and desulfurized ash (DA), a new cementitious material suitable for mine tailings was developed to replace traditional ordinary Portland cement (OPC) for reducing cement-related costs. A series of uniaxial compressive strength (UCS) tests were carried out on cemented tailings backfill (CTB) samples containing different activators. The results showed that (1) the highest UCS values of 14-day and 28-day cured CTB samples were 1.259 MPa and 2.429 MPa, respectively, and the effect of different activator types was in the order of SH > GM > DA > Q and SH > GM > Q > DA; (2) the relationship between UCS and activator dosages followed the function y = ax3 − bx2 + cx − d. Compared with the OPC 32.5 R cemented samples, the minimum strength growth factor was 1.45, and the maximum reached 2.03; (3) the optimal proportion of DA slag formula was 4.5% or 5.0% Q, 19% DA, 2.5% GM, and 0.7% SH. The aforesaid new cementitious materials met the mine’s UCS requirements with a relatively low cost (17.04–17.20 €/ton) and solved the stacking problem of solid wastes on the surface well. Ultimately, this study provides a useful reference for the development of mineral binders.

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.

Effect of Water-Soluble Carbon Nanotubes on the Mechanical Properties and early Hydration of Alkali-Activated Slag

2014 ◽  
Vol 1000 ◽  
pp. 118-121 ◽  
Author(s):  
Pavel Rovnaník ◽  
Patrik Bayer
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Cementitious Materials ◽  
Water Soluble ◽  
Strength Parameters ◽  
Early Hydration ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Hydration Characteristics ◽  
Alkali Activated

Alkali-activated slag (AAS) is a material which has great potential for use in building industry. The aim of this work was to gain new superior properties by the addition of carbon nanotubes (CNTs). This material can act as a microreinforcement improving mechanical properties of cementitious materials. The effect of 0–1 wt.% addition of CNTs on the mechanical properties, hydration characteristics and microstructure of AAS binder was determined. The addition of CNTs delays the setting of the binder and a partial deterioration of strength parameters was observed.

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.

scholarly journals Effect of Soda Residue Addition and Its Chemical Composition on Physical Properties and Hydration Products of Soda Residue-Activated Slag Cementitious Materials

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1789 ◽  
Author(s):  
Yonghui Lin ◽  
Dongqiang Xu ◽  
Xianhui Zhao
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
Cementitious Materials ◽  
Aluminum Silicate ◽  
Chemical Components ◽  
Main Role ◽  
Hydration Products ◽  
Granulated Blast Furnace Slag ◽  
Activated Slag ◽  
Main Components

Soda residue (SR), the solid waste of Na2CO3 produced by ammonia soda process, pollutes water and soil, increasing environmental pressure. SR has high alkalinity, and its main components are Ca(OH)2, NaCl, CaCl2, CaSO4, and CaCO3, which accords with the requirements of being an alkali activator. The aim of this research is to investigate the best proportion of SR addition and the contribution of individual chemical components in SR to SR- activated ground granulated blast furnace slag (GGBS) cementitious materials. In this paper, GGBS pastes activated by SR, Ca(OH)2, Ca(OH)2 + NaCl, Ca(OH)2 + CaCl2, Ca(OH)2 + CaSO4, and Ca(OH)2 + CaCO3 were studied regarding setting time, compressive strength (1 d, 3 d, 7 d, 14 d, 28 d), hydration products, and microstructure. The results demonstrate that SR (24%)-activated GGBS pastes possess acceptable setting time and compressive strength (29.6 MPa, 28 d), and its hydration products are calcium silicate hydrate (CSH) gel, calcium aluminum silicate hydrates (CASH) gel and Friedel’s salt. CaCl2 in SR plays a main role in hydration products generation and high compressive strength of SR- activated GGBS pastes.

Shrinkage of Fine-Grained Composites Based on Alkali-Activated Slag

2018 ◽  
Vol 761 ◽  
pp. 7-10 ◽  
Author(s):  
Barbara Kucharczyková ◽  
Vlastimil Bílek Jr. ◽  
Dalibor Kocáb ◽  
Ondřej Karel
Keyword(s):  
Experimental Investigation ◽  
Experimental Determination ◽  
Alkali Activated Slag ◽  
Fine Grained ◽  
Shrinkage Reducing Admixture ◽  
Activated Slag ◽  
Alkali Activated

The paper deals with the experimental determination of shrinkage development of the composites based on the alkali-activated slag (AAS). The main aim of the experimental investigation was to verify the effect of the addition of shrinkage-reducing admixture (SRA) on the overall process of shrinkage properties during AAS composites ageing.

scholarly journals Utilization of tailings in cement and concrete: A review

2019 ◽  
Vol 26 (1) ◽  
pp. 449-464 ◽  
Author(s):  
Mifeng Gou ◽  
Longfei Zhou ◽  
Nathalene Wei Ying Then
Keyword(s):  
Compressive Strength ◽  
Cementitious Materials ◽  
Solid Wastes ◽  
Supplementary Cementitious Materials ◽  
Cement Clinker ◽  
Fine Aggregate ◽  
Granulated Blast Furnace Slag ◽  
Fine Aggregates ◽  
Compressive Strength Of Concrete ◽  
Cement And Concrete

AbstractOne of the advantages of cement and the cement concrete industry in sustainability is the ability to utilize large amounts of industrial solid wastes such as fly ash and ground granulated blast furnace slag. Tailings are solid wastes of the ore beneficiation process in the extractive industry and are available in huge amounts in some countries. This paper reviews the potential utilization of tailings as a replacement for fine aggregates, as supplementary cementitious materials (SCMs) in mortar or concrete, and in the production of cement clinker. It was shown in previous research that while tailings had been used as a replacement for both fine aggregate and cement, the workability of mortar or concrete reduced. Also, at a constant water to cement ratio, the compressive strength of concrete increased with the tailings as fine aggregate. However, the compressive strength of concrete decreased as the replacement content of the tailings as SCMs increased, even whentailings were ground into smaller particles. Not much research has been dedicated to the durability of concrete with tailings, but it is beneficial for heavy metals in tailings to stabilize/solidify in concrete. The clinker can be produced by using the tailings, even if the tailings have a low SiO2 content. As a result, the utilization of tailings in cement and concrete will be good for the environment both in the solid waste processing and virgin materials using in the construction industry.

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