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.

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.

Microstructural alteration of alkali activated slag mortars depend on exposed high temperature level

2016 ◽  
Vol 104 ◽  
pp. 169-180 ◽  
Author(s):  
Hakan Tacettin Türker ◽  
Müzeyyen Balçikanli ◽  
İbrahim Halil Durmuş ◽  
Erdoğan Özbay ◽  
Mustafa Erdemir
Keyword(s):  
High Temperature ◽  
Temperature Level ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Alkali Activated

Strength and Resistance of Alkali-Activated Slag Concrete to High Temperature

2012 ◽  
Vol 193-194 ◽  
pp. 431-434 ◽  
Author(s):  
Mao Chieh Chi ◽  
Ran Huang ◽  
Wei Hsin Lu
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Relative Humidity ◽  
Superior Performance ◽  
Liquid Sodium ◽  
Temperature Resistance ◽  
Alkali Activated Slag ◽  
High Temperature Resistance ◽  
Activated Slag ◽  
Alkali Activated

This study presents an investigation into high-temperature resistance of alkali-activated slag concrete (AASC). Sodium oxide (Na2O) concentrations of 4%, 5% and 6% of slag weight and liquid sodium silicate (SiO2) with modulus ratio of 0.8 ( mass ratio of SiO2 to Na2O ) were used as activators to activate granulated blast furnace slag (GBFS). All cylindrical specimens with the same binder content and liquid/binder ratio of 0.5 were cast and cured in the air, under the saturated limewater and in a curing room at relative humidity of 80% RH and temperature of 60 °C, respectively. Test results demonstrate that the high-temperature resistance of AASC decreased with an increase of temperature. The compressive strength and high-temperature resistance of AASC improved with an increase dosage of Na2O and AASC cured at relative humidity of 80% RH and temperature of 60 °C has the superior performance, followed the AASC by air curing and saturated limewater curing. The higher compressive strength and superior high-temperature resistance have been obtained in AASC than comparable OPC.

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