Characterization of environmentally-friendly alkali activated slag cements and ancient building materials

Alkali-activated slag is known as a building material for more than sixty years and is considered an alternative to Portland cement based binders. Compared to Portland cement it exhibits some superior properties such as higher resistance against chemical attack and exposure to elevated temperatures. Aluminosilicate binders are generally electrical insulators; however, electrical properties of building materials gain the importance in the new field of applications such as self-sensing or self-heating materials. This paper brings a comparison of the electrical properties, especially resistance and capacitance, between Portland cement and alkali-activated slag mortars. The measurements revealed that alkali-activated slag shows enhanced conducting properties due to the presence of mobile hydrated sodium ions and metallic iron microparticles.

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Influence of Superplasticizer Quantity on Formation of Micro-Cracks during Setting and Hardening of Concretes by Acoustic Emission Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1124.219 ◽

2015 ◽

Vol 1124 ◽

pp. 219-224 ◽

Cited By ~ 2

Author(s):

Libor Topolář ◽

Kristýna Timcakova ◽

Petr Misák

Keyword(s):

Acoustic Emission ◽

Building Materials ◽

Material Behaviour ◽

Emission Method ◽

Alkali Activated Slag ◽

Volumetric Expansion ◽

Hardening Process ◽

Micro Cracks ◽

Activated Slag ◽

Alkali Activated

The acoustic emission phenomenon is directly associated with nucleation of cracks in building materials, therefore the changes result from the volumetric expansion causing formation micro and macro cracking in structure, which we can recognize. The main aim of the article is to compare four ways of curing alkali activated slag mortars by method of acoustic emission. A comprehension of microstructure−performance relationships is the key to true understanding of material behaviour. The results obtained in the laboratory are useful to understand the various stages of micro-cracking activity during the hardening process in quasi-brittle materials such as alkali activated slag mortars and extend them for general practice

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Electrical Properties of Alkali-Activated Slag Mortar with Carbon Fibres

Materials Science Forum ◽

10.4028/www.scientific.net/msf.908.100 ◽

2017 ◽

Vol 908 ◽

pp. 100-105 ◽

Cited By ~ 1

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.

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Flexural Fatigue Life Reliability of Alkali-Activated Slag Concrete Freeze-Thaw Damage in Cold Areas

Advances in Materials Science and Engineering ◽

10.1155/2021/1257163 ◽

2021 ◽

Vol 2021 ◽

pp. 1-20

Author(s):

Bin Chen ◽

Jun Wang

Keyword(s):

Fatigue Life ◽

Building Materials ◽

Fatigue Properties ◽

Test Results ◽

Distribution Fitting ◽

Flexural Fatigue ◽

Alkali Activated Slag ◽

Freeze Thaw ◽

Activated Slag ◽

Alkali Activated

Studying the application of alkali-activated slag concrete for roads in cold areas is of great significance for promoting and developing green building materials. In this study, the effect of freeze-thaw damage on the flexural fatigue properties of alkali-activated slag concrete was studied and the fatigue life of alkali-activated slag concrete with various degrees of damage after freeze-thaw cycles was studied through a three-point flexural test. The results show that the flexural fatigue life decreases with freeze-thaw cycles from 0 to 150 times. Through a distribution fitting test and K-S test results, the flexural fatigue life followed both the two-parameter and three-parameter Weibull distributions. Between them, the three-parameter Weibull distribution fitting had a higher accuracy and better test results. The results of the reliability analysis show that the curves of alkali-activated slag concrete samples with various degrees of freeze-thaw damage for various failure probabilities have good correlation under different stresses, and the correlation correlations were greater than 0.81. The flexural fatigue life of alkali-activated slag concrete samples with various degrees of freeze-thaw damage was more sensitive to freeze-thaw damage under high stresses. It is suggested that the fatigue design of alkali-activated slag concrete should consider the adverse effects of cold areas, and the reliability should be improved accordingly.

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