scholarly journals Combined effect of curing temperature, curing period and alkaline concentration on the mechanical properties of fly ash-based geopolymer

2021 ◽  
Vol 1 ◽  
pp. 100002
Author(s):  
Pudasaini Sajan ◽  
Tengyao Jiang ◽  
ChooiKim Lau ◽  
Gang Tan ◽  
Kam Ng
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Combined Effect ◽  
Curing Temperature ◽  
Curing Period

STUDY ON THE INFLUENCE OF CURING TEMPERATURE ON MECHANICAL PROPERTIES OF MODIFIED FLY ASH MORTAR

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Hirotaka Matsuo ◽  
Koji Takasu ◽  
Hidehiro Koyamada ◽  
Hiroki Suyama
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Strength Properties ◽  
Curing Temperature ◽  
Static Elasticity ◽  
Flotation Technique ◽  
Accumulated Temperature ◽  
Modified Fly Ash

Using fly ash as an admixture for concrete can contribute to environmental load reduction and concrete quality improvement. However, as the quality of fly ash fluctuates depending on the ash source, quality stabilization is required. It was proved that concrete with fly ash of Japanese Industrial Standardized class II has different strength properties depending on curing temperature, but it is not obvious whether concrete with modified fly ash by flotation method has similar properties. In this study, the influence was examined on the mechanical properties when changing the curing temperature of mortar using fly ash modified by the flotation technique. The sealing curing was set to 5°C, 20°C, 40°C and 60°C. Also, after 7 days, 5°C, 40°C and 60°C, is changed to 20°C and compression strength and static elasticity coefficient were measured. The value of compressive strength and static elastic modulus showed that mortar using modified fly ash had the same characteristics as mortar with ordinary fly ash. Because it was represented by one strength compressive estimation curve regardless of the curing temperature, it became clear that compressive strength can be evaluated by roughly using accumulated temperature as an indicator.

Influence of Curing Temperature on the Mechanical Properties of Alkali-Activated Bottom Ash Geopolymer Mortar

2011 ◽  
Vol 488-489 ◽  
pp. 198-201 ◽  
Author(s):  
Gum Sung Ryu ◽  
Si Hwan Kim ◽  
Kyung Taek Koh ◽  
Su Tae Kang ◽  
Jang Hwa Lee
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Power Plants ◽  
Bottom Ash ◽  
Basic Research ◽  
Molar Concentration ◽  
Curing Temperature ◽  
Active Research ◽  
Alkali Activated Concrete ◽  
Alkali Activated

The fabrication of Portland cement causes numerous problems accompanying the large exhaustion of gas. Even if fly ash, an industrial by-product produced in thermoelectric power plants, is recycled in concrete by partial replacing of cement, more than 50% remains still discharged in marine and ashore landfills and, continue to provoke environmental problems. Recently, active research has been dedicated to alkali-activated concrete that does not use cement as binder. This alkali-activated concrete as a cement zero concrete activated by alkali solution using bottom ash rich in Si and Al instead of cement is effective in reducing gas exhaustion. This study is a basic research for the fabrication of concrete without cement and using 100% of bottom ash among the industrial by-products. Therefore, the purposes are to develop cement zero concrete by evaluating the mechanical properties by age according to the change of the molar concentration and ratio (SH/SS) of the alkali-activator and the curing temperature, and to investigate the reaction mechanism. From the test results, the compressive strength increased with larger molar concentration and the optimal curing temperature was 60°C. In addition, the measurement of the leaching according to the molar concentration of fly ash having similar chemical composition showed that the leaching of Si4+ and Al3+ increased. Compared to 6M, the leached quantities of Si4+ and Al3+ were twice larger for 9M and 12M. The formation of gel at the surface of fly ash indicated that fly ash was more activated in higher alkaline environment.

Evolution of thermal and mechanical properties of mine tailings and fly ash mixtures during curing period

2014 ◽  
Vol 51 (5) ◽  
pp. 570-582 ◽  
Author(s):  
Joon Kyu Lee ◽  
Julie Q. Shang
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Fly Ash ◽  
Mine Tailings ◽  
Mechanical Characteristics ◽  
Early Stage ◽  
Expansive Soils ◽  
Thermal And Mechanical Properties ◽  
Curing Period ◽  
Compaction Energy

Fly ash is often used as a binder for modifying the properties of geomaterials, such as organic and expansive soils, sludge from water treatment, dredged sediments, mine tailings, etc. Changes in thermal and mechanical properties of compacted mixtures of mine tailings and fly ash are studied over a curing period of 120 h. The study includes the measurement of thermal conductivity, temperature, unconfined compressive strength, and elastic modulus. Effects of the amount of fly ash added to mine tailings, molding water content, and compaction energy on these properties are investigated. Pore-size distribution and surface texture are analyzed to characterize the microstructures of fly ash treated–mine tailings. Relationships between the thermal conductivity and properties that capture packing and mechanical characteristics of mine tailings and fly ash mixtures are established. These observations provide enhanced understanding of thermal, mechanical, and structural properties of fly ash–treated mine tailings, which is associated with the hydration process at the early stage of the mixtures.

scholarly journals Effect of Calcium Carbonate Whisker and Fly Ash on Mechanical Properties of Cement Mortar under High Temperatures

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Li Wang ◽  
Hongliang Zhang ◽  
Bendong Zhao ◽  
Yang Gao
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Fly Ash ◽  
Calcium Carbonate ◽  
High Temperatures ◽  
Coupling Effect ◽  
Microstructural Analysis ◽  
Cementitious Materials ◽  
Combined Effect ◽  
Superior Performance

Calcium carbonate (CaCO3) whisker, as a new type of microfibrous material, has been extensively used in the reinforcement of cementitious materials. However, the combined effect of CaCO3 whisker and fly ash on mechanical properties of cementitious materials under high temperatures was still unknown. In this study, the coupling effect of CaCO3 whisker, and fly ash on mechanical properties of the cement was investigated. Two sets of cement mortars were fabricated, including CaCO3 whisker-based mortar which contained 0 wt.%, 5 wt.%, 10 wt.%, 15 wt.%, and 20 wt.% CaCO3 whisker as cement substitution and CaCO3 whisker-based fly ash mortar which contained 30 wt.% fly ash in addition to 0 wt.%, 5 wt.%, 10 wt.%, 15 wt.%, and 20 wt.% CaCO3 whisker as cement substitution. Mass loss, compressive strength, and flexural strength of these two sets of specimens before and after being subjected to high temperatures of 200°C, 400°C, 600°C, 800°C, and 1000°C were measured. Based on the results of the aforementioned tests, load-deflection test was performed on the specimen which exhibited the superior performance to further study its mechanical behavior after exposure to high temperatures. Moreover, microstructural analysis, such as mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM), was conducted to reveal the damage mechanism of high temperature and to illustrate the combined effect of CaCO3 whisker and fly ash on high-temperature resistance of the cement. Results showed that fly ash could improve the high-temperature performance of CaCO3 whisker-based mortar before 600°C and limit the loss of strength after 600°C.

Effects of Various Additives on Drying Shrinkage, Compressive and Flexural Strength of Lightweight Foamed Concrete (LFC)

2012 ◽  
Vol 626 ◽  
pp. 594-604 ◽  
Author(s):  
Ahmad Farhan Roslan ◽  
Hanizam Awang ◽  
Md Azree Othuman Mydin
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Drying Shrinkage ◽  
Polypropylene Fibre ◽  
Microstructure Formation ◽  
Pozzolanic Material ◽  
Curing Period ◽  
Foamed Concrete

This paper presents an investigation on lightweight foamed concrete (LFC) with different type of additives. LFC with 600, 1000 and 1400 kg/m3 density were cast and tested. Fly ash, lime and polypropylene fibre were used on each density with different percentages. All the additives effects were compared with normal LFC as control mix. Mechanical properties of LFC were evaluated with several tests up to 180 days. The results show that the drying shrinkage, compressive strength and flexural strength are affected by the hydration process of each additive in the harden LFC. Fly ash as pozzolanic material helps to strengthen the LFC, though it needs longer curing period to achieve ultimate strength. Lime gives slight contribution to strength as detail investigation on microstructure formation will give clear answer on how the mechanical properties were affected. The addition of polypropylene contributes to flexural strength and shrinkage of LFC. Polypropylene fibre only contributes to compressive strength at low LFC density.

Mechanical Properties of Alkali Activated Fly Ash Geopolymer Stabilized Expansive Clay

2019 ◽  
Vol 23 (9) ◽  
pp. 3875-3888 ◽  
Author(s):  
Anant Lal Murmu ◽  
Anamika Jain ◽  
Anjan Patel
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Expansive Clay ◽  
Alkali Activated

scholarly journals Mechanical Behavior of Brick Masonry in an Acidic Atmospheric Environment

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2694 ◽  
Author(s):  
Shansuo Zheng ◽  
Lihua Niu ◽  
Pei Pei ◽  
Jinqi Dong
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Acid Rain ◽  
Cement Mortar ◽  
Brick Masonry ◽  
Atmospheric Environment ◽  
Peak Strain ◽  
Lime Mortar ◽  
Attenuation Model

In order to evaluate the deterioration regularity for the mechanical properties of brick masonry due to acid rain corrosion, a series of mechanical property tests for mortars, bricks, shear prisms, and compressive prisms after acid rain corrosion were conducted. The apparent morphology and the compressive strength of the masonry materials (cement mortar, cement-lime mortar, cement-fly ash mortar, and brick), the shear behavior of the masonry, and the compression behavior of the masonry were analyzed. The resistance of acid rain corrosion for the cement-lime mortar prisms was the worst, and the incorporation of fly ash into the cement mortar did not improve the acid rain corrosion resistance. The effect of the acid rain corrosion damage on the mechanical properties for the brick was significant. With an increasing number of acid rain corrosion cycles, the compressive strength of the mortar prisms, and the shear and compressive strengths of the brick masonry first increased and then decreased. The peak stress first increased and then decreased whereas the peak strain gradually increased. The slope of the stress-strain curve for the compression prisms gradually decreased. Furthermore, a mathematical degradation model for the compressive strength of the masonry material (cement mortar, cement-lime mortar, cement-fly ash mortar, and brick), as well as the shear strength attenuation model and the compressive strength attenuation model of brick masonry after acid rain corrosion were proposed.

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