Freeze-Thaw Resistance with Sodium Chloride Solution of Fly-Ash Concrete Mixtures

2015 ◽  
Vol 1124 ◽  
pp. 137-144
Author(s):  
Tomáš Váchal ◽  
Rostislav Šulc ◽  
Pavel Svoboda
Keyword(s):  
Fly Ash ◽  
Sodium Chloride ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Freeze Thaw ◽  
Fly Ash Concrete ◽  
Air Content ◽  
Concrete Mixtures ◽  
Alkali Activated Concrete ◽  
Alkali Activated

This paper describes freeze-thaw resistance with sodium chloride solution of concrete mixtures based on alkali-activated fly ash. There are shown relationships between freeze-thaw resistance with sodium chloride solution and air content in fresh alkali-activated concrete and relationship between freeze-thaw resistance with sodium chloride solution and spacing factor of alkali-activated concrete. Also there is described relationship between air content in fresh mixture and compressive strength of alkali-activated concrete.

Rheological Characteristics of Alkali Activated Fly-Ash Concrete Mixtures

2016 ◽  
Vol 677 ◽  
pp. 86-92
Author(s):  
Tomáš Váchal ◽  
Rostislav Šulc ◽  
Pavel Svoboda
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Fresh Concrete ◽  
Rheological Characteristics ◽  
Fresh Mixture ◽  
Fly Ash Concrete ◽  
Concrete Mixtures ◽  
Alkali Activated Concrete ◽  
Alkali Activated

This paper describes rheological characteristics of concrete mixtures based on alkali-activated fly ash. There are shown relationships between workability of fly-ash fresh concrete mixtures and water–fly-ash ratio in fresh alkali-activated concrete. In addition, there is described relationship between workability in fresh mixture on compressive strength of alkali-activated concrete.

scholarly journals Use of Silica Fume and GGBS to Improve Frost Resistance of ECC with High-Volume Fly Ash

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yushi Liu ◽  
Xiaoming Zhou ◽  
Chengbo Lv ◽  
Yingzi Yang ◽  
Tianan Liu
Keyword(s):  
Elastic Modulus ◽  
Sodium Chloride ◽  
Mass Loss ◽  
Frost Resistance ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Tap Water ◽  
High Volume ◽  
Dynamic Elastic Modulus ◽  
Freeze Thaw

Fly ash (FA) has been an important ingredient for engineered cementitious composite (ECC) with excellent tensile strain capacity and multiple cracking. Unfortunately, the frost resistance of ECC with high-volume FA has always been a problem. This paper discusses the influence of silica fume (SF) and ground-granulated blast-furnace slag (GGBS) on the frost resistance of ECC with high volume of FA. Four ECC mixtures, ECC (50% FA), ECC (70% FA), ECC (30% FA + 40% SL), and ECC (65% FA + 5% SF), are evaluated by freezing-thawing cycles up to 200 cycles in tap water and sodium chloride solution. The result shows the relative dynamic elastic modulus and mass loss of ECC in sodium chloride solution by freeze-thaw cycles are larger than those in tap water by freeze-thaw cycles. Moreover, the relative dynamic elastic modulus and mass loss of ECC by freeze-thaw cycles increase with FA content increasing. However, the ECC (30% FA + 40% SL) shows a lower relative dynamic elastic modulus and mass loss, but its deflection upon four-point bending test is relatively smaller before and after freeze-thaw cycles. By contrast, the ECC (65% FA + 5% SF) exhibits a significant deflection increase with higher first cracking load, and the toughness increases sharply after freeze-thaw cycles, meaning ECC has good toughness property.

scholarly journals Alkali-Activated Slag/ Fly Ash Concrete: Mechanism, Properties, Hydration Product and Curing Temperature

2020 ◽  
Vol 9 (9) ◽  
pp. 204-215
Keyword(s):  
Fly Ash ◽  
Hydration Product ◽  
Test Methods ◽  
Curing Temperature ◽  
Environmental Friendliness ◽  
Alkali Activated Slag ◽  
Fly Ash Concrete ◽  
Activated Slag ◽  
Alkali Activated Concrete ◽  
Alkali Activated

Alkali-activated concrete (AAC) is mounting as a feasible alternative to OPC assimilated to reduce greenhouse gas emanated during the production of OPC. Use of pozzolana results in gel over-strengthening and fabricate less quantity of Ca(OH)2 which provide confrontation to concrete against hostile environment. (AAC) is potential due to inheriting the property of disbursing CO2 instantly from the composition. Contrastingly an option to ordinary Portland cement (OPC), keeping this fact in mind the goal to evacuate CO2 emits and beneficiate industrial by-products into building material have been taken into consideration. Production of alkali-activated cement emanates CO2 nearly 50-80% less than OPC. This paper is the general assessment of current report on the fresh and hardened properties of alkali-activated fly ash (AAF), alkali-activated slag (AAS), and alkali activated slag and fly ash (AASF) concrete. In the recent epoch, there has been a progression to blend slag with fly ash to fabricate ambient cured alkali-activated concrete. Along with that the factors like environmental friendliness, advanced studies and investigation are also mandatorily required on the alkali activated slag and fly ash concrete. In this way, the slag to fly ash proportion impacts the essential properties and practical design of AAC. This discusses and reports the issue in an intensive manner in the following sections. This will entail providing a good considerate of the following virtues like workability, compressive strength, tensile strength, durability issues, ambient and elevated-temperature curing of AAC which will improve further investigation to elaborate the correct test methods and to commercialize it.

Effect of Specimen Size and Curing Condition on the Compressive Strength of Alkali-Activated Concrete

2017 ◽  
Vol 2629 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Robert James Thomas ◽  
Sulapha Peethamparan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Specimen Size ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Slag Cement ◽  
Fly Ash Concrete ◽  
Activated Slag ◽  
Alkali Activated Concrete ◽  
Alkali Activated

Alkali-activated concrete is a rapidly emerging sustainable alternative to portland cement concrete. The compressive strength behavior of alkali-activated concrete has been reported by various studies to a limited extent, but these discussions have been based on minimal evidence. Furthermore, although it is known that specimen size has a distinct effect on the apparent compressive strength of concrete, this effect has yet to be modeled for alkali-activated concrete. This paper presents the results of a comprehensive study of the effects of curing condition (i.e., moist-cured at ambient temperature for 28 days or heat-cured at 50çC for 48 h) and specimen size on the compressive strength of sodium silicate–activated fly ash and slag cement concrete. The heat-cured strength of alkali-activated slag cement concrete was linearly related to the moist-cured strength; the former was about 5% greater than the latter. Heat curing also improved the strength of alkali-activated fly ash concrete, although the effect was greatly magnified for lower-strength mixtures and was much less significant at higher strengths. Existing size effect laws employed for portland cement concrete proved reasonably accurate in describing the effect of specimen size on the apparent strength of alkali-activated slag cement concrete. However, these existing models greatly underestimated the size effect in alkali-activated fly ash concrete; the authors suggest that this finding was the result of significant microcracking in the alkali-activated fly ash concrete.

Use of Ash after Denitrification as an Additive to Concrete Based on Alcali-Activated Slag

2021 ◽  
Vol 322 ◽  
pp. 78-83
Author(s):  
Lukáš Procházka ◽  
Jana Boháčová
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Partial Replacement ◽  
Negative Effects ◽  
Concrete Mixtures ◽  
Granulated Slag ◽  
Activated Slag ◽  
Alkali Activated Concrete ◽  
Alkali Activated ◽  
Reference Mixture

This paper deals with the possibility of using fly ash after denitrification by the SNCR method a partial replacement in alkali-activated concrete based on blast furnace granulated slag. Previous research has verified the use of fly ash after denitrification in alkali-activated materials based on blast furnace granulated slag, and so far no negative effects on the properties of these mixtures have been found. The tests were performed on cement test specimens. As part of the preparation of concrete mixtures, two recipes were prepared. The first reference mixture contained only blast furnace granulated slag activated by sodium water glass with silicate modulus of 2. The second recipe was modified by replacing of 30% slag by fly ash after denitrification by SNCR method. Within the strength characteristics, the reference mixture always achieved better results. Very slow increases in strength were recorded for the mixture with 30% slag replacement by fly ash, when the compressive strength after 7 days of maturation was only 4.5 MPa.

Extraction of heavy metals from MSWI fly ash using hydrochloric acid and sodium chloride solution

2018 ◽  
Vol 76 ◽  
pp. 457-471 ◽  
Author(s):  
Gisela Weibel ◽  
Urs Eggenberger ◽  
Dmitrii A. Kulik ◽  
Wolfgang Hummel ◽  
Stefan Schlumberger ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Fly Ash ◽  
Sodium Chloride ◽  
Hydrochloric Acid ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Mswi Fly Ash
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