scholarly journals Electrical and Self-Sensing Properties of Alkali-Activated Slag Composite with Graphite Filler

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1616 ◽  
Author(s):  
Pavel Rovnaník ◽  
Ivo Kusák ◽  
Patrik Bayer ◽  
Pavel Schmid ◽  
Lukáš Fiala
Keyword(s):  
Mechanical Properties ◽  
Electrical Properties ◽  
Compressive Loading ◽  
Conductive Filler ◽  
Graphite Powder ◽  
Alkali Activated Slag ◽  
Sensing Properties ◽  
Activated Slag ◽  
Conductive Properties ◽  
Alkali Activated

The electrical properties of concrete are gaining their importance for the application in building construction. In this study, graphite powder was added to alkali-activated slag mortar as an electrically conductive filler in order to enhance the mortar’s conductive properties. The amount of graphite ranged from 1% to 30% of the slag mass. The effect of the graphite powder on the resistivity, capacitance, mechanical properties, and microstructure of the composite was investigated. Selected mixtures were then used for the testing of self-sensing properties under compressive loading. The results show that the addition of an amount of graphite equal to up to 10% of the slag mass improved the electrical properties of the alkali-activated slag. Higher amounts of filler did not provide any further improvement in electrical properties at lower AC frequencies but caused a strong deterioration in mechanical properties. The best self-sensing properties were achieved for the mixture with 10 wt% of graphite, but only at low compressive stresses of up to 6 MPa.

Self-Sensing Properties of Alkali-Activated Slag Composite with Carbon Black during Bending Test

2019 ◽  
Vol 296 ◽  
pp. 167-172 ◽  
Author(s):  
Pavel Rovnaník ◽  
Cecílie Mizerová ◽  
Ivo Kusák ◽  
Pavel Schmid
Keyword(s):  
Carbon Black ◽  
Conductive Filler ◽  
Bending Test ◽  
Self Monitoring ◽  
Alkali Activated Slag ◽  
Sensing Properties ◽  
Three Point Bending ◽  
Compressive And Flexural Strengths ◽  
Activated Slag ◽  
Alkali Activated

Aluminosilicate materials are generally considered electrical insulators. In order to achieve enhanced electrical conductivity these materials must doped with suitable conductive admixtures such as carbon black. These composites gain the importance in the new field of applications such as self-sensing materials or self-monitoring structures. This paper presents a study on self-sensing properties of alkali-activated slag composite with 2 and 4% of carbon black as conductive filler during repeated flexural and till fracture loading in the configuration of three-point bending test. The results showed that best performance of the self-sensing properties was achieved with 4% of carbon black, though both the compressive and flexural strengths were deteriorated.

Electrical Properties of Alkali-Activated Slag Mortar with Carbon Fibres

2017 ◽  
Vol 908 ◽  
pp. 100-105 ◽  
Author(s):  
Pavel Rovnaník ◽  
Maria Míková ◽  
Ivo Kusák
Keyword(s):  
Mechanical Properties ◽  
Electrical Properties ◽  
Building Materials ◽  
Specific Conductivity ◽  
Carbon Fibres ◽  
Alkali Activated Slag ◽  
Order Of Magnitude ◽  
Activated Slag ◽  
Mixing Water ◽  
Alkali Activated

Building materials with enhanced electrical properties gain the importance in the new field of applications such as self-sensing or self-heating materials. In this paper, 3 mm long carbon fibres were used as a conductive admixture to alkali-activated slag mortar in order to reduce its resistivity. The amount of carbon fibres was ranging from 0.5 to 4.0% of the slag mass and the effect of the conductive admixture on the mechanical properties, electrical impedance, specific conductivity, and microstructure of alkali-activated slag composite was investigated. Only 0.5% of carbon fibres caused a significant decrease in impedance of alkali-activated slag composite and the addition of 4% reduced the impedance by one order of magnitude for low AC frequencies. However, due to problematic dispersion and higher demand of mixing water, the mechanical properties were deteriorated, especially at higher content of carbon fibres.

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 Investigation of Graphene Derivatives on Electrical Properties of Alkali Activated Slag Composites

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4374
Author(s):  
Wu-Jian Long ◽  
Xuanhan Zhang ◽  
Biqin Dong ◽  
Yuan Fang ◽  
Tao-Hua Ye ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrical Properties ◽  
Mechanical Performance ◽  
Structural Defects ◽  
Alkali Activated Slag ◽  
Mechanical And Electrical Properties ◽  
Reduced Graphene ◽  
Graphene Derivatives ◽  
Activated Slag ◽  
Alkali Activated

Reduced graphene oxide (rGO) has been widely used to modify the mechanical performance of alkali activated slag composites (AASC); however, the mechanism is still unclear and the electrical properties of rGO reinforced AASC are unknown. Here, the rheological, mechanical, and electrical properties of the AASC containing rGO nanosheets (0, 0.1, 0.2, and 0.3 wt.%) are investigated. Results showed that rGO nanosheets addition can significantly improve the yield stress, plastic viscosity, thixotropy, and compressive strength of the AASC. The addition of 0.3 wt.% rGO nanosheets increased the stress, viscosity, thixotropy, and strength by 186.77 times, 3.68 times, 15.15 times, and 21.02%, respectively. As for electrical properties, the impedance of the AASC increased when the rGO content was less than 0.2 wt.% but decreased with the increasing dosage. In contrast, the dielectric constant and electrical conductivity of the AASC containing rGO nanosheets decreased and then increased, which can be attributed to the abundant interlayer water and the increasing structural defects as the storage sites for charge carriers, respectively. In addition, the effect of graphene oxide (GO) on the AASC is also studied and the results indicated that the agglomeration of GO nanosheets largely inhibited the application of it in the AASC, even with a small dosage.

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.

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.

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