Use of recycled aggregates as internal curing agent for alkali-activated slag system

2018 ◽  
Vol 159 ◽  
pp. 286-296 ◽  
Author(s):  
Nam Kon Lee ◽  
Selamu Yihune Abate ◽  
Hyeong-Ki Kim
Keyword(s):  
Slag System ◽  
Internal Curing ◽  
Recycled Aggregates ◽  
Curing Agent ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Alkali Activated

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.

scholarly journals Impacts of Casting Scales and Harsh Conditions on the Thermal, Acoustic, and Mechanical Properties of Indoor Acoustic Panels Made with Fiber-Reinforced Alkali-Activated Slag Foam Concretes

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 825 ◽  
Author(s):  
Mastali Mohammad ◽  
Kinnunen Paivo ◽  
Karhu Marjaana ◽  
Abdollahnejad Zahra ◽  
Korat Lidija ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Comparative Study ◽  
Sound Absorption ◽  
Acoustic Properties ◽  
Recycled Aggregates ◽  
Fiber Reinforced ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Harsh Conditions ◽  
Alkali Activated

This paper presents experimental results regarding the efficiency of using acoustic panels made with fiber-reinforced alkali-activated slag foam concrete containing lightweight recycled aggregates produced by using Petrit-T (tunnel kiln slag). In the first stage, 72 acoustic panels with dimension 500 × 500 × 35 mm were cast and prepared. The mechanical properties of the panels were then assessed in terms of their compressive and flexural strengths. Moreover, the durability properties of acoustic panels were studied using harsh conditions (freeze/thaw and carbonation tests). The efficiency of the lightweight panels was also assessed in terms of thermal properties. In the second stage, 50 acoustic panels were used to cover the floor area in a reverberation room. The acoustic absorption in diffuse field conditions was measured, and the interrupted random noise source method was used to record the sound pressure decay rate over time. Moreover, the acoustic properties of the panels were separately assessed by impedance tubes and airflow resistivity measurements. The recorded results from these two sound absorption evaluations were compared. Additionally, a comparative study was presented on the results of impedance tube measurements to compare the influence of casting volumes (large and small scales) on the sound absorption of the acoustic panels. In the last stage, a comparative study was implemented to clarify the effects of harsh conditions on the sound absorption of the acoustic panels. The results showed that casting scale had great impacts on the mechanical and physical properties. Additionally, it was revealed that harsh conditions improved the sound properties of acoustic panels due to their effects on the porous structure of materials.

scholarly journals Internal curing by superabsorbent polymers in alkali-activated slag

2020 ◽  
Vol 135 ◽  
pp. 106123 ◽  
Author(s):  
Zhenming Li ◽  
Mateusz Wyrzykowski ◽  
Hua Dong ◽  
José Granja ◽  
Miguel Azenha ◽  
...  
Keyword(s):  
Internal Curing ◽  
Superabsorbent Polymers ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Alkali Activated

scholarly journals Effect of Internal Curing by Super Absorbent Polymer on the Autogenous Shrinkage of Alkali-Activated Slag Mortars

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4318
Author(s):  
Pengju Wang ◽  
Haiming Chen ◽  
Peiyuan Chen ◽  
Jin Pan ◽  
Yangchen Xu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
Autogenous Shrinkage ◽  
Internal Curing ◽  
Engineering Properties ◽  
Super Absorbent Polymer ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Absorbent Polymer ◽  
Alkali Activated

Alkali activated slag (AAS) mortar is becoming an increasingly popular green building material because of its excellent engineering properties and low CO2 emissions, promising to replace ordinary Portland cement (OPC) mortar. However, AAS’s high shrinkage and short setting time are the important reasons to limit its wide application in engineering. This paper was conducted to investigate the effect of internal curing(IC) by super absorbent polymer (SAP) on the autogenous shrinkage of AAS mortars. For this, an experimental study was carried out to evaluate the effect of SAP dosage on the setting time, autogenous shrinkage, compressive strength, microstructure, and pore structure. The SAP were incorporated at different dosage of 0, 0.05, 0.1, 0.2, 0.3, 0.4, and 0.5 percent by weight of slag. The workability, physical (porosity), mechanical, and shrinkage properties of the mortars were evaluated, and a complementary study on microstructure was made. The results indicated that the setting time increased with an increase of SAP dosage due to the additional activator released by SAP. Autogenous shrinkage decreased with an increase of SAP dosage, and was mitigated completely when the dosage of SAP ≥ 0.2% wt of slag. Although IC by means of SAP reduced the compressive strength, this reduction (23% at 56 days for 0.2% SAP) was acceptable given the important role that it played on mitigating autogenous shrinkage. In the research, the 0.2% SAP dosage was the optimal content. The results can provide data and basis for practical application of AAS mortar.

scholarly journals Effects of Light-Burnt Dolomite Incorporation on the Setting, Strength, and Drying Shrinkage of One-Part Alkali-Activated Slag Cement

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2874 ◽  
Author(s):  
In Kyu Jeon ◽  
Jae Suk Ryou ◽  
Sadam Hussain Jakhrani ◽  
Hong Gi Kim
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Setting Time ◽  
Drying Shrinkage ◽  
Slag System ◽  
Strength Development ◽  
Alkali Activated Slag ◽  
Granulated Blast Furnace Slag ◽  
Activated Slag ◽  
Alkali Activated

This study investigates the potential of light-burnt dolomite (LBD) as a supplementary cementitious material with ground granulated blast furnace slag (GGBFS) and Ordinary Portland cement (OPC). In this work, LBD was substituted for up to 20% of GGBFS in sodium sulfate-activated slag systems. The effects of LBD incorporation on the flow, setting time, compressive and flexural strength development, and drying shrinkage were explored with, X-ray diffraction and thermogravimetric analyses. LBD incorporation resulted in greater strength development of an alkali-activated slag system. The optimum LBD content for strength development was 10%, regardless of ordinary Portland cement content. In addition, LBD decreased the drying shrinkage, accelerated the hydration process, and induced hydrotalcite formation, which can be attributed to the reactive MgO inside LBD.

scholarly journals Internal curing of alkali-activated slag-fly ash paste with superabsorbent polymers

2020 ◽  
Vol 263 ◽  
pp. 120985 ◽  
Author(s):  
Zhenming Li ◽  
Shizhe Zhang ◽  
Xuhui Liang ◽  
José Granja ◽  
Miguel Azenha ◽  
...  
Keyword(s):  
Fly Ash ◽  
Internal Curing ◽  
Superabsorbent Polymers ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Alkali Activated
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