The Identification of Cracks Formed during the Spontaneous Drying and Hardening of Alkali-Activated Slag for Different Curing Times

2016 ◽  
Vol 827 ◽  
pp. 340-343
Author(s):  
Libor Topolář ◽  
Hana Šimonová ◽  
Lubos Pazdera
Keyword(s):  
Brittle Materials ◽  
Material Behaviour ◽  
Alkali Activated Slag ◽  
Hardening Process ◽  
Curing Method ◽  
Activated Slag ◽  
Alkali Activated

This paper reports the results of measurements during hardening and drying of specimens made of alkali activated slag mortars. The aim of this paper is introduce the effect of curing method and time on the microstructure of alkali activated slag mortars. An understanding 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 field applications.

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

2015 ◽  
Vol 1124 ◽  
pp. 219-224 ◽  
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

scholarly journals Effect of Heat Curing Method on the Mechanical Strength of Alkali-Activated Slag Mortar after High-Temperature Exposure

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1789 ◽  
Author(s):  
Tai Thanh Tran ◽  
Hyuk Kang ◽  
Hyug-Moon Kwon
Keyword(s):  
High Temperature ◽  
Mechanical Strength ◽  
Weight Ratio ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Alkali Activated Slag ◽  
Heat Curing ◽  
Curing Method ◽  
Activated Slag ◽  
Alkali Activated

The aim of this work was to study the mechanical strength and microstructure changes of alkali-activated slag mortar (AAS mortar) after being heat treated in the temperature range of 200–1000 °C. The AAS mortar was cured in the ambient condition (20 ± 5 °C, 60 ± 5% RH) (Relative humidity: RH) and high temperature condition (80 °C) for 27 days with three different heating regimes: curing in a dry oven, curing in sealed plastic bags, and in a steam environment. The activator for the AAS synthesis was a mixture of sodium silicate solution (water glass) and sodium hydroxide (NaOH) with a SiO2/Na2O weight ratio of 1, and a dosage of 4% Na2O by slag weight. Thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) incorporated with energy-dispersive X-ray spectroscopy (EDX) were used to assess the mortar microstructure change. The results revealed that the curing method significantly affected the mechanical strength of AAS at temperatures lower than 800 °C. The heat treatment at late age of 28 days was more beneficial for compressive strength enhancement in specimens without using heat curing methods.

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