scholarly journals The Influence of Sodium Hydroxide Concentration on Physical Properties and Strength Development of High Calcium Fly Ash Based Geopolymer as Pavement Base Materials

2020 ◽  
Vol 864 ◽  
pp. 012016
Author(s):  
Liyana Ahmad Sofri ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Mohd Rosli Mohd Hasan ◽  
Yue Huang
Keyword(s):  
Fly Ash ◽  
Physical Properties ◽  
Sodium Hydroxide ◽  
Strength Development ◽  
Sodium Hydroxide Concentration ◽  
Base Materials ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Pavement Base

High calcium fly ash geopolymer stabilized lateritic soil and granulated blast furnace slag blends as a pavement base material

2018 ◽  
Vol 341 ◽  
pp. 257-267 ◽  
Author(s):  
Itthikorn Phummiphan ◽  
Suksun Horpibulsuk ◽  
Runglawan Rachan ◽  
Arul Arulrajah ◽  
Shui-Long Shen ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Base Material ◽  
Lateritic Soil ◽  
Granulated Blast Furnace Slag ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Pavement Base ◽  
Furnace Slag

Experiment and Micro-Mechanism Study on Mechanical Properties and Durability of High-Calcium Fly Ash Concrete

2011 ◽  
Vol 480-481 ◽  
pp. 59-65
Author(s):  
Shuang Xi Li ◽  
Tuan She Yang ◽  
Zhi Ming Wang ◽  
Quan Hu
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Frost Resistance ◽  
Strength Development ◽  
Hydration Reaction ◽  
Optimal Dosage ◽  
Fly Ash Concrete ◽  
Low Calcium ◽  
High Calcium ◽  
High Calcium Fly Ash

Low-calcium fly ash is paid much attention for its wide use in engineering, the research and application technology of it are very mature, but as to high-calcium fly ash concrete, the researches on stability, mechanical property and durability of it are very less , The existing researches are still inadequate for practice of engineering. As to this problem, using small shek kip hydropower project as example, the volume stability of high-calcium fly ash concretes with different fly ash dosages are tested, then the optimal dosage of the high-calcium fly ash is determined; based on this, the impacts of high-calcium fly ash on the performance of mechanical properties , impermeability and frost resistance of concrete are studied; Finally, macro performance is analyzed from a micro-mechanism point of view through taking the electron micrograph. As the study shows, the optimal dosage of high-calcium fly ash should be taken as 20% -25%; for the concrete with special requirements, the dosage can be relaxed to 30% when the high-calcium fly ash achieves high quality. The compressive strength of high-calcium fly ash concrete is higher than the low-calcium fly ash concrete. Strength development advantage of high-calcium fly ash concrete reflects at the early age, this advantage takes the trend of weakening as the development of age. Concrete mixed with high-calcium fly ash has good performance in impermeability. The high-calcium fly ash has high activity, the high-calcium fly ash and secondary hydration reaction products can be filled into the pore capillary and cracks of the concrete structure, improving the pore structure, thereby increasing the density of cement paste. High-calcium fly ash concrete has good performance in frost resistance. The destructive effects of freeze-thaw cycles on cement structure has connection with the microstructure of cement and impermeability , the improvement of impermeability avoids the water entering into the concrete, reduces the risk of destruction caused by frost heave.The study on micro-mechanism proves well the macro-phenomena above.

scholarly journals Durability Study on High Calcium Fly Ash Based Geopolymer Concrete

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Ganesan Lavanya ◽  
Josephraj Jegan
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Sodium Hydroxide ◽  
Ordinary Portland Cement ◽  
Geopolymer Concrete ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Ordinary Portland Cement Concrete

This study presents an investigation into the durability of geopolymer concrete prepared using high calcium fly ash along with alkaline activators when exposed to 2% solution of sulfuric acid and 5% magnesium sulphate for up to 45 days. The durability was also assessed by measuring water absorption and sorptivity. Ordinary Portland cement concrete was also prepared as control concrete. The grades chosen for the investigation were M20, M40, and M60. The alkaline solution used for present study is the combination of sodium silicate and sodium hydroxide solution with the ratio of 2.50. The molarity of sodium hydroxide was fixed as 12. The test specimens were150×150×150 mm cubes,100×200 mm cylinders, and100×50 mm discs cured at ambient temperature. Surface deterioration, density, and strength over a period of 14, 28, and 45 days were observed. The results of geopolymer and ordinary Portland cement concrete were compared and discussed. After 45 days of exposure to the magnesium sulfate solution, the reduction in strength was up to 12% for geopolymer concrete and up to 25% for ordinary Portland cement concrete. After the same period of exposure to the sulphuric acid solution, the compressive strength decrease was up to 20% for geopolymer concrete and up to 28% for ordinary Portland cement concrete.

scholarly journals Influence of Concrete Sludge Addition in the Properties of Alkali-Activated and Non-Alkali-Activated Fly Ash-Based Mortars

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Fotini Kesikidou ◽  
Stavroula Konopisi ◽  
Eleftherios K. Anastasiou
Keyword(s):  
Fly Ash ◽  
Silicon Oxide ◽  
Strength Development ◽  
Alkali Activation ◽  
Early Age ◽  
Fly Ash Concrete ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Potential Synergy ◽  
Alkali Activated

This study investigated the use of concrete sludge, a by-product of the ready-mix concrete industry, in combination with high-calcium fly ash in binary cementless binders. Concrete sludge was used in substitution rates ranging from 0% to 60% in test fly ash-based mortars to determine potential synergy. The mortars were tested for fresh and hardened properties; workability, viscosity, strength development, open porosity, early-age shrinkage, and analytical tests were carried out. A mortar with 50% fly ash and 50% limestone filler as binders was used for comparison purposes. Furthermore, a series of mortars with fly ash and concrete sludge were alkali-activated in order to determine potential strength gain. In the activated mortars, two fractions of concrete sludge were used, under 75 μm and 200 μm, due to different silicon oxide contents, while one mortar was cured at 40°C to investigate the effect of heating on alkali activation. Results show that sludge contributes to the formation of C-S-H and strength development when used in combination with high-calcium fly ash even at high replacement rates. The alkali activation of fly ash-concrete sludge system contributed to early-age strength development and to early-age shrinkage reduction.

Effect of Addition of Microsilica and Nanoalumina on Compressive Strength and Products of High Calcium Fly Ash Geopolymer with Low Concentration NaOH

2015 ◽  
Vol 1103 ◽  
pp. 29-36 ◽  
Author(s):  
Prinya Chindaprasirt ◽  
Kiatsuda Somna
Keyword(s):  
Compressive Strength ◽  
Salicylic Acid ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Product Form ◽  
Leaching Test ◽  
Low Concentration ◽  
High Calcium ◽  
High Calcium Fly Ash

This research aims to study the effect of addition of microsilica and nanoalumina on compressive strength and products of high calcium fly ash geopolymer with low NaOH concentration. Microsilica and nanoalumina were added in the mixture in order to adjust the Si/Al ratios which resulted in the change of product form of geopolymer pastes. Geopolymer was synthesized using high calcium fly ash and 2 molar sodium hydroxide (NaOH). Microsilica and/or nanoalumina were added as additional sources of silica and alumina in the mixtures. Compressive strengths of pastes were investigated at the age of 7, 28 and 60 days. The products of geopolymer pastes were characterized by FTIR and salicylic acid with methanol (SAM leaching test). The results showed that the mix (2Si10Al0) with additional 10% of microsilica gave the highest compressive strength of 14 MPa at the age of 60 days. The products of geopolymer pastes were CSH gel, CASH gel, NASH gel and zeolite which were characterized by FTIR and SAM leaching test.

Effect of sodium hydroxide and sodium silicate solutions on strengths of alkali activated high calcium fly ash containing Portland cement

2016 ◽  
Vol 21 (6) ◽  
pp. 2202-2210 ◽  
Author(s):  
Tanakorn Phoo-ngernkham ◽  
Sakonwan Hanjitsuwan ◽  
Nattapong Damrongwiriyanupap ◽  
Prinya Chindaprasirt
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Alkali Activated

scholarly journals Geopolymer Mortar Incorporating High Calcium Fly Ash and Silica Fume

2019 ◽  
Vol 65 (1) ◽  
pp. 3-16 ◽  
Author(s):  
V.C. Prabha ◽  
V. Revathi
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Silica Fume ◽  
Sodium Hydroxide Solution ◽  
Test Results ◽  
Dense Microstructure ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Binder Ratio

AbstractAn attempt was made in the present work to study the compressive strength and microstructure of geopolymer containing high calcium fly ash (HCFA) and silica fume. Concentration of sodium hydroxide solution 8M, 10M, 12M & 14M, liquid to binder ratio 0.5 and sodium hydroxide to sodium silicate ratio 2.5 were selected for the mixes. Geopolymer mortar test results indicated that the mix with 40% silica fume by the weight of HCFA yielded higher compressive strength under ambient curing. The XRD pattern typically shows the major portion of amorphous phase of geopolymer. The existence of C-A-S-H gel, N-A-S-H gel and hydroxysodalite gel products were observed through SEM which developed dense microstructure and thus enhanced strength of HCFA and silica fume geopolymer.

Factors Influence on Shrinkage of High Calcium Fly Ash Geopolymer Paste

2012 ◽  
Vol 610-613 ◽  
pp. 2275-2281 ◽  
Author(s):  
Parames Kamhangrittirong ◽  
Prasert Suwanvitaya ◽  
Watcharin Witayakul ◽  
Patcharaporn Suwanvitaya ◽  
Prinya Chindaprasirt
Keyword(s):  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Hydroxide Solution ◽  
Construction Materials ◽  
Weight Ratio ◽  
Drying Shrinkage ◽  
Shrinkage Strain ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Geopolymer Paste

This research shows the progress of geopolymer synthesis based on high calcium fly ash. In this study, the fly ash contents of 60, 65, and 70 percents by weight and sodium hydroxide solution concentrations of 8 to 12 M were used. Alkali activators for the geopolymer synthesis consisted of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) and the weight ratio of Na2SiO3 to NaOH were 0.50, 1.00, and 1.50. Drying shrinkage deformation of geopolymer paste was investigated by longitudinal measurement in a room temperature. Generally, the drying shrinkage behavior could be divided into three groups. The minimum drying shrinkage strain below 3,000 x 10-6 mm/mm was observed. The results indicated that an increase in the fly ash to alkali solution ratio and the decease of NaOH concentration significantly decreased the drying shrinkage strain. The optimum ratio of Na2SiO3 to NaOH was 1.0. The findings show that high calcium fly ash geopolymer binder could be used for alternative construction materials with low shrinkage strain.

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