Durability Study on High Calcium Fly Ash Based Geopolymer 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.

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Characterisation at the Bonding Zone between Fly Ash Based Geopolymer Repair Materials (GRM) and Ordinary Portland Cement Concrete (OPCC)

Materials ◽

10.3390/ma14010056 ◽

2020 ◽

Vol 14 (1) ◽

pp. 56

Author(s):

Warid Wazien Ahmad Zailani ◽

Mohd Mustafa Al Bakri Abdullah ◽

Mohd Fadzil Arshad ◽

Rafiza Abd Razak ◽

Muhammad Faheem Mohd Tahir ◽

...

Keyword(s):

Fly Ash ◽

Portland Cement ◽

Ordinary Portland Cement ◽

Repair Material ◽

Portland Cement Concrete ◽

Cement Concrete ◽

Repair Materials ◽

High Calcium ◽

Bonding Zone ◽

Ordinary Portland Cement Concrete

In recent years, research and development of geopolymers has gained significant interest in the fields of repairs and restoration. This paper investigates the application of a geopolymer as a repair material by implementation of high-calcium fly ash (FA) as a main precursor, activated by a sodium hydroxide and sodium silicate solution. Three methods of concrete substrate surface preparation were cast and patched: as-cast against ordinary Portland cement concrete (OPCC), with drilled holes, wire-brushed, and left as-cast against the OPCC grade 30. This study indicated that FA-based geopolymer repair materials (GRMs) possessed very high bonding strength at early stages and that the behavior was not affected significantly by high surface treatment roughness. In addition, the investigations using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy have revealed that the geopolymer repair material became chemically bonded to the OPC concrete substrate, due to the formation of a C–A–S–H gel. Fundamentally, the geopolymer network is composed of tetrahedral anions (SiO4)4− and (AlO4)5− sharing the oxygen, which requires positive ions such as Na+, K+, Li+, Ca2+, Na+, Ba2+, NH4+, and H3O+. The availability of calcium hydroxide (Ca(OH)2) at the surface of the OPCC substrate, which was rich in calcium ions (Ca2+), reacted with the geopolymer; this compensated the electron vacancies of the framework cavities at the bonding zone between the GRM and the OPCC substrate.

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Study on Residual Splitting Tensile Strength of HFCC after High Temperature

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.243-249.5067 ◽

2011 ◽

Vol 243-249 ◽

pp. 5067-5070 ◽

Cited By ~ 1

Author(s):

Fu Ping Jia ◽

Yong Cheng ◽

Yi Bing Sun ◽

Yin Yu Wang ◽

Hao Sun

Keyword(s):

Tensile Strength ◽

High Temperature ◽

Fly Ash ◽

Portland Cement ◽

Ordinary Portland Cement ◽

Splitting Tensile Strength ◽

Portland Cement Concrete ◽

Cement Concrete ◽

Splitting Strength ◽

Ordinary Portland Cement Concrete

This paper presents the results of the splitting tensile strength of high fly ash content concrete (HFCC) after high temperature and analysis the degraded rules of the residual splitting strength subjected to high temperature and the replacements of cement by fly ash. The specimens were prepared with three different replacements of cement by fly ash 30%, 40% and 50% by mass and were tested after exposure to high temperature 250, 450, 550 and 650°C and room temperature respectively, compared with ordinary Portland cement concrete. The results showed that the splitting tensile strength sensitively decreased with the high temperature increased. Furthermore, the presence of fly ash was effective for improvement of the relative strength. The relative residual splitting strength of fly ash concrete was higher than those of ordinary Portland cement concrete except 30% fly ash replacement. Based on the experiments results, the alternating simulation formula to determine the relationship among relative residual strength, high temperature and fly ash replacement is developed by using regression of results, which provides the theoretical basis for the evaluation and repair of HFCC after high temperature.

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Investigation of engineering properties of normal and high strength fly ash based geopolymer and alkali-activated slag concrete compared to ordinary Portland cement concrete

Construction and Building Materials ◽

10.1016/j.conbuildmat.2018.11.083 ◽

2019 ◽

Vol 196 ◽

pp. 26-42 ◽

Cited By ~ 32

Author(s):

Nabeel A. Farhan ◽

M. Neaz Sheikh ◽

Muhammad N.S. Hadi

Keyword(s):

Fly Ash ◽

Portland Cement ◽

Ordinary Portland Cement ◽

High Strength ◽

Engineering Properties ◽

Portland Cement Concrete ◽

Cement Concrete ◽

Alkali Activated Slag ◽

Activated Slag ◽

Alkali Activated

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Alkali-activated concrete versus ordinary Portland cement concrete and Roman concrete when using sea sand and seawater

10.1016/b978-0-323-85469-6.00018-0 ◽

2022 ◽

pp. 257-303

Author(s):

Minhao Dong ◽

Mohamed Elchalakani

Keyword(s):

Portland Cement ◽

Ordinary Portland Cement ◽

Portland Cement Concrete ◽

Cement Concrete ◽

Sea Sand ◽

Roman Concrete ◽

Alkali Activated Concrete ◽

Alkali Activated ◽

Ordinary Portland Cement Concrete

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EXPLORATORY STUDY ON THE MECHANICAL AND PHYSICAL PROPERTIES OF CONCRETE CONTAINING SULFUR

Jurnal Teknologi ◽

10.11113/jt.v77.7009 ◽

2015 ◽

Vol 77 (32) ◽

Cited By ~ 3

Author(s):

David Yeoh ◽

Koh Heng Boon ◽

Norwati Jamaluddin

Keyword(s):

Portland Cement ◽

Physical Properties ◽

Ordinary Portland Cement ◽

Cement Content ◽

Drying Shrinkage ◽

Portland Cement Concrete ◽

Cement Concrete ◽

Complete Replacement ◽

Mechanical And Physical Properties ◽

Ordinary Portland Cement Concrete

This research is an exploratory experiment into sulfur concrete used not as a complete replacement of cement but as an additional material in percentage of the cement content. The aim of this research was to explore the possible appreciation of mechanical and physical properties of concrete containing sulfur with percentages of 1%, 5% and 10% of the cement content. The sulfur used here was not heat-activated, hence the binding effect in sulfur was absent. The experimental results revealed that concrete containing sulfur did not perform better in their strength properties, both compressive strength and flexural strength. The physical properties such as water penetration and water absorption for concrete containing sulfur also showed poor performance in comparison to ordinary Portland cement concrete. Such phenomena are very likely due to the sulfur not being activated by heat. Carbonation test did not show good results as a longer term of testing is required. Drying shrinkage property was found to be encouraging in that concrete containing 10% sulfur had quite significant reduction in drying shrinkage as opposed to ordinary Portland cement concrete.

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