Chloride Resistance of Alkali Activated Slag Pastes with Fly Ash Replacement

2016 ◽  
Vol 851 ◽  
pp. 98-103
Author(s):  
Ladislav Pařízek ◽  
Vlastimil Bílek Jr. ◽  
Matěj Březina

High energy requirements due to producing of Portland cement leads to a tendency to use secondary raw materials or completely new kind of materials. One of the possibilities is using the materials based on alkali activated slag (AAS). In this paper the influence of partial replacement of ground granulated blast furnace slag by fly ash in AAS pastes on mechanical properties and porosity of was investigated. For practical applications it is also necessary to know their resistance to environment such as salty water. Chloride resistance was investigated by setting the experiment as external chloride attack and measuring the changes of mechanical properties, porosity and composition of the pastes.

2014 ◽  
Vol 1000 ◽  
pp. 137-140
Author(s):  
Vlastimil Bílek Jr. ◽  
Lukáš Kalina ◽  
Eva Bartoníčková ◽  
Tomáš Opravil

One of the highest shortages of alkali-activated slag (AAS) is high shrinkage, both autogenous and drying. One of the possibilities of lowering the shrinkage is partial replacement of slag by suitable admixtures, which can act for example through the forming of expansive hydration products. In this study, 0–50 % of slag was replaced by by-pass cement kiln dust and fluidized bed combustion fly ash. Promising results were obtained especially in the case of fly ash. By using admixtures at higher dosages compressive strengths were reduced.


2021 ◽  
Vol 291 ◽  
pp. 123312
Author(s):  
Renjuan Sun ◽  
Chen Fang ◽  
Hongzhi Zhang ◽  
Yifeng Ling ◽  
Jingjing Feng ◽  
...  

2021 ◽  
Vol 13 (4) ◽  
pp. 2407
Author(s):  
Guang-Zhu Zhang ◽  
Xiao-Yong Wang ◽  
Tae-Wan Kim ◽  
Jong-Yeon Lim ◽  
Yi Han

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.


2018 ◽  
Vol 761 ◽  
pp. 73-78 ◽  
Author(s):  
Matej Špak ◽  
Pavel Raschman

Alkali-activated materials based on fly ash are widely developed and also produced on the present. Some of fly ashes are not suitable for production of alkali-activated materials because of their inconvenient chemical composition. Alumina-silicates are the most important components that are needed to accomplish the successful reaction. The proper content of amorphous phase of alumina-silicates and its proportion as well should be provided for the final composition of alkali-activated materials. The influence of pure aluminum oxide powder as well as raw milled natural perlite on mechanical properties and durability of alkali-activated mortars was investigated. These minerals were used as partial replacement of fly ash coming from black coal combustion. In addition, the mortars were prepared by using different alkali activators.


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