Efficiency of natural pozzolans, ground glasses and coal bottom ashes in mitigating sulfate attack and alkali-silica reaction

2021 ◽  
Vol 149 ◽  
pp. 106551
Author(s):  
Mahipal Kasaniya ◽  
Michael D.A. Thomas ◽  
Edward G. Moffatt
Keyword(s):  
Sulfate Attack ◽  
Alkali Silica Reaction ◽  
Natural Pozzolans

scholarly journals Durability of concrete containing ternary blends of high calcium fly ash and slag

2021 ◽  
Author(s):  
Seyon Kandasamy
Keyword(s):  
Fly Ash ◽  
Setting Time ◽  
Sulfate Attack ◽  
Alkali Silica Reaction ◽  
Ternary Blends ◽  
Fresh Properties ◽  
Freeze Thaw ◽  
Salt Scaling ◽  
High Calcium ◽  
High Calcium Fly Ash

This thesis investigates the performance of ternary blends containing high calcium fly ash (HCFA) and slag against: sulfate attack, alkali-silica reaction (ASR), salt scaling, and freeze-thaw damage. In addition, compressive strength, permeability and fresh properties were evaluated. In terms of sulfate attack, the performance of HCFA was significantly enhanced when slag was added to the mix, and the same was found for ASR. The high efficacy in resisting ASR of HCFA/slag blends was found to be a result of the blends' ability to bind and retain alkalis. Regarding the salt scaling, the tested ternary concretes failed the Ministry of Transportation Ontario limit, 0.8 kg/m²; however, enhanced performance was achieved when the samples were cured by wrapping with plastic sheets. Ternary blends achieved high resistance to freezing/thawing and less bleeding compared to those of the control mix without slag or HCFA; however, setting time was dragged by about an hour.

Effect of Mineral Admixtures on Durability of Concrete Structure Subjected to Alkaline Saline Corrosions

2006 ◽  
Vol 302-303 ◽  
pp. 68-72
Author(s):  
Quan Lin Niu ◽  
Nai Qian Feng
Keyword(s):  
Chloride Ion ◽  
Sulfate Attack ◽  
Mineral Admixtures ◽  
Alkali Silica Reaction ◽  
Sulfate Ion ◽  
Diffusion Test ◽  
Alkali Ions ◽  
Furnace Slag ◽  
Drying Test ◽  
Durability Of Concrete

Effect of a combination of alkali ions, sulfate ion and chloride ion on durability of concrete structures was analyzed, and the effect of different mineral admixtures on deterioration caused by Cl- penetration, sulfate attack and alkali-silica reaction was investigated. It is shown from wetting-drying test that sulfate attack on concrete was greatly relieved in high Cl- concentration solution, but diffusion test showed that Cl- diffusion was accelerated by SO4 2- ion existence as SO4 2- may incorporate with aluminum phase prior to Cl- ion. Replacement of cement with mineral admixtures such as ground blast furnace slag (SL) and metalaolin (MK) were beneficial for absorption of Cl- ion penetrated into paste, while ASTM C441 showed that fly ash (FA), metakaolin and natural zeolite (NZ) exhibited effectiveness in controlling Alkali-silica reaction (ASR).

Role of Alkalis in Natural Pozzolans on Alkali-Silica Reaction

2021 ◽  
Vol 118 (3) ◽  
Author(s):  
Ryan D. Kalina ◽  
Saif Al-Shmaisani ◽  
Saamiya Seraj ◽  
Rachel Cano ◽  
Raissa Douglas Ferron ◽  
...  
Keyword(s):  
Alkali Silica Reaction ◽  
Natural Pozzolans

Micro-Macro Material Performance Tests of One Attacked Building Foundation

2014 ◽  
Vol 1004-1005 ◽  
pp. 1478-1481
Author(s):  
Run Dong Gao ◽  
Hai Bin Chen
Keyword(s):  
Compressive Strength ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Energy Dispersive Spectrometer ◽  
Sulfate Attack ◽  
Alkali Silica Reaction ◽  
Performance Tests ◽  
Concrete Compressive Strength ◽  
Building Foundation ◽  
Scanning Electron

One 6-stories brick-concrete structure was built in the late of 1990s. The uneven settlement of the foundation had occurred and the average concrete compressive strength of the foundation was close to C30 standard. Apparent observations indicated that some white powdery substance which was not adhesive was precipitated at the aggregate/mortar interface, pores and cracks. Micro observations by means of a Scanning Electron Microscope equipped with a Energy Dispersive Spectrometer showed the coexistence of ettringite and small amount of alkali–silica gel, which proved that the foundation had suffered from sulfate attack and alkali–silica reaction.

Scientific Basis for Determining the Sulfate Resistance of Blended Cements

1987 ◽  
Vol 113 ◽  
Author(s):  
P. K. Mehta
Keyword(s):  
Scientific Basis ◽  
Sulfate Attack ◽  
Chemical Processes ◽  
Critical Examination ◽  
Blended Cements ◽  
Sulfate Resistance ◽  
Natural Pozzolans ◽  
Iron Blast Furnace ◽  
Physical And Chemical ◽  
Furnace Slag

ABSTRACTThe physical and chemical processes underlying the sulfate attack on concrete are briefly reviewed with special reference to blended portland cements containing natural pozzolans, fly ash, or granulated iron blast-furnace slag. Published literature contains empirical guidelines for evaluating the suitability of blending materials for sulfate resistance; however a critical examination shows that some of the guidelines are not satisfactory. Ideas for establishing a scientific basis for determining the sulfate resistance of blended cements are presented in the paper.

scholarly journals Durability of concrete containing ternary blends of high calcium fly ash and slag

2021 ◽  
Author(s):  
Seyon Kandasamy
Keyword(s):  
Fly Ash ◽  
Setting Time ◽  
Sulfate Attack ◽  
Alkali Silica Reaction ◽  
Ternary Blends ◽  
Fresh Properties ◽  
Freeze Thaw ◽  
Salt Scaling ◽  
High Calcium ◽  
High Calcium Fly Ash

This thesis investigates the performance of ternary blends containing high calcium fly ash (HCFA) and slag against: sulfate attack, alkali-silica reaction (ASR), salt scaling, and freeze-thaw damage. In addition, compressive strength, permeability and fresh properties were evaluated. In terms of sulfate attack, the performance of HCFA was significantly enhanced when slag was added to the mix, and the same was found for ASR. The high efficacy in resisting ASR of HCFA/slag blends was found to be a result of the blends' ability to bind and retain alkalis. Regarding the salt scaling, the tested ternary concretes failed the Ministry of Transportation Ontario limit, 0.8 kg/m²; however, enhanced performance was achieved when the samples were cured by wrapping with plastic sheets. Ternary blends achieved high resistance to freezing/thawing and less bleeding compared to those of the control mix without slag or HCFA; however, setting time was dragged by about an hour.

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