The Effect of Fly Ash on Resistance of Hardened Cement Pastes to Sodium Chloride Attack

2011 ◽  
Vol 12 (1) ◽  
pp. 84-89 ◽  
Author(s):  
A.E. AL-Salami
Keyword(s):  
Fly Ash ◽  
Sodium Chloride ◽  
Hardened Cement ◽  
Cement Pastes ◽  
Chloride Attack ◽  
Hardened Cement Pastes

Influence of Fly Ash on Alkalinity of Pore Solution and Microstructure Characteristics of Hardened Cement Pastes

2012 ◽  
Vol 253-255 ◽  
pp. 322-325 ◽  
Author(s):  
Jian Jun Yan ◽  
Xiang Li ◽  
Hua Quan Yang
Keyword(s):  
Fly Ash ◽  
Pore Solution ◽  
Cementitious Material ◽  
Ex Situ ◽  
Hardened Cement ◽  
Cement Pastes ◽  
Microstructure Characteristics ◽  
Hardened Cement Pastes ◽  
Very High ◽  
Reaction Degree

Influence of fly ash on alkalinity of pore solution and microstructure characteristics of hardened cement pastes were investigated by means of ex-situ leaching (ESL), MIP and SEM. The results reveal that the decline of alkalinity of pore solution is not endless, even though the contents of fly ash in fly ash-cement(FC) pastes is very high(65%).The incorporation of fly ash in proper ratios could increase the ratio of harmless pores and improve the microstructure of the FC pastes. Ca(OH)2 was not consumed heavily or exhausted when cementitious material was hydrated due to the low reaction degree of fly ash.

Long term study of hardened cement pastes containing silica fume and fly ash

2014 ◽  
Vol 60 ◽  
pp. 48-56 ◽  
Author(s):  
Vili Lilkov ◽  
Ivan Rostovsky ◽  
Ognyan Petrov ◽  
Yana Tzvetanova ◽  
Plamen Savov
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Hardened Cement ◽  
Term Study ◽  
Cement Pastes ◽  
Long Term Study ◽  
Hardened Cement Pastes

scholarly journals New Approach for the Determination of Radiological Parameters on Hardened Cement Pastes with Coal Fly Ash

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 475
Author(s):  
Ana María Moreno de los Reyes ◽  
José Antonio Suárez-Navarro ◽  
Maria del Mar Alonso ◽  
Catalina Gascó ◽  
Isabel Sobrados ◽  
...  
Keyword(s):  
Fly Ash ◽  
Activity Concentration ◽  
Gamma Ray ◽  
Coal Fly Ash ◽  
Cementitious Materials ◽  
New Method ◽  
Supplementary Cementitious Materials ◽  
Hardened Cement ◽  
Cement Pastes ◽  
Activity Concentrations

Supplementary cementitious materials (SCMs) in industrial waste and by-products are routinely used to mitigate the adverse environmental effects of, and lower the energy consumption associated with, ordinary Portland cement (OPC) manufacture. Many such SCMs, such as type F coal fly ash (FA), are naturally occurring radioactive materials (NORMs). 226Ra, 232Th and 40K radionuclide activity concentration, information needed to determine what is known as the gamma-ray activity concentration index (ACI), is normally collected from ground cement samples. The present study aims to validate a new method for calculating the ACI from measurements made on unground 5 cm cubic specimens. Mechanical, mineralogical and radiological characterisation of 28-day OPC + FA pastes (bearing up to 30 wt % FA) were characterised to determine their mechanical, mineralogical and radiological properties. The activity concentrations found for 226Ra, 212Pb, 232Th and 40K in hardened, intact 5 cm cubic specimens were also statistically equal to the theoretically calculated values and to the same materials when ground to a powder. These findings consequently validated the new method. The possibility of determining the activity concentrations needed to establish the ACI for cement-based materials on unground samples introduces a new field of radiological research on actual cement, mortar and concrete materials.

scholarly journals Effect of Some Acrylate—Poly(Ethylene Glycol) Copolymers as Superplasticizers on the Mechanical and Surface Properties of Portland Cement Pastes

2005 ◽  
Vol 23 (3) ◽  
pp. 245-254 ◽  
Author(s):  
S.A. Abo-El-Enein ◽  
S. Hanafi ◽  
F.I. El-Hosiny ◽  
El-Said H.M. El-Mosallamy ◽  
M.S. Amin
Keyword(s):  
Ethylene Glycol ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Mechanical Characteristics ◽  
Hardened Cement ◽  
Poly Ethylene Glycol ◽  
Cement Pastes ◽  
Surface Areas ◽  
Poly Ethylene ◽  
Hardened Cement Pastes

Ordinary Portland cement (OPC) pastes with added superplasticizer were made using water/cement weight ratios of standard consistency. Three types of superplasticizer based on acrylate—poly(ethylene glycol) copolymers were used. The pastes were hydrated for various time lengths and the mechanical characteristics of the hardened cement pastes were studied and related to their pore structures. It was found that the addition of the superplasticizers to OPC improved the mechanical properties of the hardened pastes for all hydration lengths. The addition of such superplasticizers to OPC resulted in a decrease in the specific surface areas and total pore volumes of the hardened superplasticized cement pastes relative to the corresponding hardened neat cement pastes.

Assessment of Anhydrous Ethanol Extraction to Determine the Ionic Concentration of Hardened Cement Pastes

2010 ◽  
Vol 177 ◽  
pp. 506-509 ◽  
Author(s):  
Man Jian Wu ◽  
Wu Yao ◽  
Wei Wang ◽  
Yong Qi Wei
Keyword(s):  
Pore Solution ◽  
Ph Value ◽  
Ionic Concentration ◽  
Anhydrous Ethanol ◽  
Hardened Cement ◽  
Cement Pastes ◽  
Ethanol Extraction ◽  
Alkali Ions ◽  
Ph Values ◽  
Hardened Cement Pastes

A new method involving the extraction of various ions from hardened cement pastes by anhydrous ethanol is presented to determine the pH value and ionic concentration during the first 28 days. The volume content of pore solution extracted by ethanol in the leachate reached 12% or above and the pH values calculated by alkali ions are more than 12, even up to 12.73. The results were compared with those from parallel, conventional pore water expression experiments. All of these comparisons verified the feasibility of the proposed method. However, the application of this method to pore solution analysis needs further improvement.

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