The Characteristics of Alkali-Activated Slag Mortar containing Multi-Walled Carbon Nanotubes at Elevated Temperature

2021 ◽  
pp. 1-23
Author(s):  
Arash Sedaghatdoost ◽  
Kiachehr Behfarnia ◽  
Mohammad Bayati ◽  
Ali Hendi ◽  
Mohammad Sadegh Vaezi
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Mass Loss ◽  
Elevated Temperatures ◽  
Alkali Activated Slag ◽  
Ambient Temperatures ◽  
Multi Walled Carbon Nanotubes ◽  
Activated Slag ◽  
Walled Carbon Nanotubes ◽  
Alkali Activated

In the present paper, the effect of using multi-walled carbon nanotubes (MWCNTs) with different concentrations of 0, 0.05, 0.1, and 0.15 wt% on the mechanical properties and microstructure of alkali-activated slag (AAS) mortars at temperatures of 23, 200, 400, 600, and 800°C was investigated. In order to investigate the strength parameters of specimens, the mechanical strength and mass-loss of the specimens at ambient temperatures and after exposure to elevated temperatures were determined. Petrographic image analysis also was conducted to analyze the microstructures of the specimens. Moreover, the Image processing toolbox of Matlab software was used to calculate the pore area of the samples at room temperature. The results showed that the application of MWCNTs improved the mechanical properties of the AAS mortars at ambient and elevated temperatures. The addition of the MWCNTs improved the mechanical properties of the AAS mortars up to 69 and 85% for compressive and flexural strength, respectively. At 400°C, compressive strength increment of the specimens compensated the deterioration rate, which was about 3% mass-loss and this temperature should be considered the maximum tolerable degree for AAS mortars.

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.

Effect of Carbon Nanotubes and Hydroxypropyl Methylcellulose on the Mechanical Properties and Cracking Tendency of Alkali-Activated Slag

2015 ◽  
Vol 1100 ◽  
pp. 25-29
Author(s):  
Peter Rypák ◽  
Libor Topolář ◽  
Pavel Rovnaník
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Hydroxypropyl Methylcellulose ◽  
Impact Echo ◽  
Alkali Activated Slag ◽  
Major Disadvantage ◽  
Activated Slag ◽  
Positive Effect ◽  
Cracking Tendency ◽  
Alkali Activated

Alkali-activated slag (AAS) is a material which has great potential for use in building industry. However, its major disadvantage is an increased shrinkage followed by formation of microcracks. The aim of this work was to investigate the influence of carbon nanotubes and hydroxypropyl methylcellulose on the mechanical properties and cracking tendency of alkali-activated slag material. The results showed that both admixtures have a positive effect on compressive as well as flexural strength. Impact-echo measurement revealed that both admixtures reduce cracking tendency and can retain water in the binder.

scholarly journals Alkali-Activated Slag cement: Alternative Adhesives for CFRP Sheets Bonded to Concrete at Elevated Temperatures

2020 ◽  
Vol 23 (3) ◽  
pp. 167-176
Author(s):  
Jing Zhu ◽  
Wenzhong Zheng ◽  
Lili Xie ◽  
Ning Ren ◽  
Yuxuan Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperatures ◽  
Heating Temperature ◽  
High Strength ◽  
Slag Cement ◽  
Alkali Activated Slag ◽  
Cfrp Sheets ◽  
Effects Of Temperature ◽  
Activated Slag ◽  
Alkali Activated

The properties and microstructures of alkali-activated slag cement (AASC) exposed to 20~1200°C were probed in this paper. The aim is to develop an eco-friendly fireproof high-strength adhesive with an optimum ratio and evaluate its usability for CFRP sheets bonded to concrete. The blast furnace slag and fly ash were employed as source materials (activated by potassium silicate, NaOH and Portland cement). The effects of slag content, activator nature and heating temperature on the compressive or bond properties were analyzed. The microstructures of the AASC exposed to different high temperatures were studied by two different techniques, including SEM and XRD analyses. The effects of temperature on the mechanical properties of AASC were first rising then descending, and the basic reason for the degradation of macro-mechanical properties is the deterioration of AASC microstructure. It is proved that AASC has comparable reinforcing effects as those of organic epoxy matrix.

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 Enhancement of out-of-plane mechanical properties of carbon fiber reinforced epoxy resin composite by incorporating the multi-walled carbon nanotubes

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Seyed Ali Mirsalehi ◽  
Amir Ali Youzbashi ◽  
Amjad Sazgar
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Tensile Test ◽  
Epoxy Resin ◽  
Laminate Composite ◽  
Filament Winding ◽  
Hybrid Nanocomposites ◽  
Out Of Plane ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

AbstractIn this study, epoxy hybrid nanocomposites reinforced by carbon fibers (CFs) were fabricated by a filament winding. To improve out-of-plane (transverse) mechanical properties, 0.5 and 1.0 Wt.% multi-walled carbon nanotubes (MWCNTs) were embedded into epoxy/CF composites. The MWCNTs were well dispersed into the epoxy resin without using any additives. The transverse mechanical properties of epoxy/MWCNT/CF hybrid nanocomposites were evaluated by the tensile test in the vertical direction to the CFs (90º tensile) and flexural tests. The fracture surfaces of composites were studied by scanning electron microscopy (SEM). The SEM observations showed that the bridging of the MWCNTs is one of the mechanisms of transverse mechanical properties enhancement in the epoxy/MWCNT/CF composites. The results of the 90º tensile test proved that the tensile strength and elongation at break of nanocomposite with 1.0 Wt.% MWCNTs improved up to 53% and 50% in comparison with epoxy/CF laminate composite, respectively. Furthermore, the flexural strength, secant modulus, and elongation of epoxy/1.0 Wt.% MWCNT/CF hybrid nanocomposite increased 15%, 7%, and 9% compared to epoxy/CF laminate composite, respectively.

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