Effect of internal curing by superabsorbent polymers – Internal relative humidity and autogenous shrinkage of alkali-activated slag mortars

2016 ◽  
Vol 123 ◽  
pp. 198-206 ◽  
Author(s):  
Chiwon Song ◽  
Young Cheol Choi ◽  
Seongcheol Choi
Keyword(s):  
Relative Humidity ◽  
Autogenous Shrinkage ◽  
Internal Curing ◽  
Superabsorbent Polymers ◽  
Alkali Activated Slag ◽  
Internal Relative Humidity ◽  
Activated Slag ◽  
Alkali Activated

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 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

scholarly journals Internal Curing Effect of Pre-Soaked Zeolite Sand on the Performance of Alkali-Activated Slag

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 718
Author(s):  
Guang-Zhu Zhang ◽  
Han-Seung Lee ◽  
Xiao-Yong Wang ◽  
Yi Han
Keyword(s):  
Compressive Strength ◽  
Electrical Resistivity ◽  
Natural Zeolite ◽  
Setting Time ◽  
Autogenous Shrinkage ◽  
Internal Curing ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Two Stages ◽  
Alkali Activated

This study clarifies the effects of pre-soaked zeolite sand as an internal curing material on the hydration, strength, autogenous shrinkage, and durability of alkali-activated slag (AAS) mortars. The liquid-to-binder ratio (L/b) of all of the AAS mortars was 0.55. Sodium hydroxide solution was used as an alkali activator and an internal curing liquid. Calcined zeolite and natural zeolite sand replaced the standard sand at 15% and 30%, respectively. The setting time, autogenous shrinkage, compressive strength, ultrasonic pulse velocity, and surface electrical resistivity were tested. The following conclusions were drawn: (1) The addition of zeolite significantly reduces the autogenous shrinkage of AAS mortar. Compared with the control group, 30% calcined zeolite reduced the autogenous shrinkage by 96.4%. Moreover, the autogenous shrinkage of the AAS mortars was noticed in two stages (a variable temperature stage and an ambient temperature stage), and the two stages split at one day of age. (2) The compressive strength of all of the specimens increased as the zeolite sand content increased, and the highest compressive strength was obtained for AAS combined with 30% natural zeolite sand. (3) Internal curing accelerated the formation of the second peak of heat flow and reduced the accumulated heat release. (4) Calcined zeolite sand delayed the setting time of the AAS mortars. (5) The addition of zeolite significantly reduced the surface electrical resistivity of the AAS mortars. In summary, zeolite sand is extremely useful as an internal curing agent to reduce autogenous shrinkage and to increase the compressive strength of AAS mortars.

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.

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