scholarly journals Effects of Microwave Energy on Fast Compressive Strength Development of Coal Bottom Ash-Based Geopolymers

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sungil Hong ◽  
Hyo Kim
Keyword(s):  
Compressive Strength ◽  
Moisture Content ◽  
Structural Integrity ◽  
Bottom Ash ◽  
Free Water ◽  
Strength Loss ◽  
Microwave Energy ◽  
Strength Development ◽  
Coal Bottom Ash ◽  
Effective Manner

Abstract Microwave energy has been shown to be effective for geopolymer synthesis due to its fast and penetrative heating characteristics; however, the changes in the physicochemical properties of the geopolymer, resulting from the microwave irradiation, have not been fully elucidated. Therefore, this study is aimed at investigating the effect of the microwaving on the properties of coal bottom ash(CBA) geopolymers. We prepared geopolymer samples by casting a mixture of ground CBA and 14 M NaOH solution against cubic molds with a hand press machine, followed by pre-curing in a dry oven at 75 °C for 24 h and microwaving under various powers and durations. The compressive strength strongly depended on the moisture content, i.e., the strength increased from 21 to 65 MPa or higher as the moisture content decreased to critical values, after which the strength began to decrease. The results showed that microwave energy stimulated an additional geopolymerization by evaporating the redundant free water. This led to the strength gain, although the over-irradiation generated a high internal stress and poor structural integrity, which resulted in the strength loss. Therefore, the appropriate application of microwave energy is a promising option for synthesizing high-strength geopolymers in a cost- and time-effective manner.

scholarly journals Positive Influence of Liquid Sodium Silicate on the Setting Time, Polymerization, and Strength Development Mechanism of MSWI Bottom Ash Alkali-Activated Mortars

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1927
Author(s):  
Lei Jin ◽  
Guodong Huang ◽  
Yongyu Li ◽  
Xingyu Zhang ◽  
Yongsheng Ji ◽  
...  
Keyword(s):  
Sodium Silicate ◽  
Setting Time ◽  
Bottom Ash ◽  
Free Water ◽  
Polymerization Reaction ◽  
Liquid Sodium ◽  
Strength Development ◽  
Mswi Bottom Ash ◽  
Alkali Activated ◽  
Development Mechanism

Setting time and mechanical properties are key metrics needed to assess the properties of municipal solid waste incineration (MSWI) bottom ash alkali-activated samples. This study investigated the solidification law, polymerization, and strength development mechanism in response to NaOH and liquid sodium silicate addition. Scanning electron microscopy and X-ray diffraction were used to identify the formation rules of polymerization products and the mechanism of the underlying polymerization reaction under different excitation conditions. The results identify a strongly alkaline environment as the key factor for the dissolution of active substances as well as for the formation of polymerization products. The self-condensation reaction of liquid sodium silicate in the supersaturated state (caused by the loss of free water) is the major reason for the rapid coagulation of alkali-activated samples. The combination of both NaOH and liquid sodium silicate achieves the optimal effect, because they play a compatible coupling role.

scholarly journals Prediction of Compressive Strength Behavior of Ground Bottom Ash Concrete by an Artificial Neural Network

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Kraiwut Tuntisukrarom ◽  
Raungrut Cheerarot
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Compressive Strength ◽  
Bottom Ash ◽  
Strength Development ◽  
Ann Model ◽  
Explicit Equation ◽  
Strength Behavior ◽  
Artificial Neural ◽  
Hidden Layer

The objective of this work was to examine the compressive strength behavior of ground bottom ash (GBA) concrete by using an artificial neural network. Four input parameters, specifically, the water-to-binder ratio (WB), percentage replacement of GBA (PR), median particle size of GBA (PS), and age of concrete (AC), were considered for this prediction. The results indicated that all four considered parameters affect the strength development of concrete, and GBA with a high fineness can act as a good pozzolanic material. The optimal ANN model had an architecture with two hidden layers, with six neurons in the first hidden layer and one neuron in the second hidden layer. The proposed ANN-based explicit equation represented a highly accurate predictive model, for which the statistical values of R2 were higher than 0.996. Moreover, the compressive strength behavior determined using the optimal ANN model closely followed the trend lines and surface plots of the experimental results.

Soluble Pozzolanic Materials from Coal Bottom Ash as Cement Replacement Material

2021 ◽  
Vol 879 ◽  
pp. 68-80
Author(s):  
Rahimah Embong ◽  
Andri Kusbiantoro ◽  
Azrina Abd Wahab ◽  
Khairunisa Muthusamy
Keyword(s):  
Industrial Waste ◽  
Bottom Ash ◽  
Cumulative Effect ◽  
Soluble Form ◽  
Recycling Rate ◽  
Strength Development ◽  
Coal Bottom Ash ◽  
Cement Replacement ◽  
Soluble Silica ◽  
Pozzolanic Materials

Nowadays, intensive research in production of highly reactive pozzolanic materials from industrial waste to replace cement is crucial. This action expected to increase industrial waste recycling rate and at the same time reduce extraction of non-renewable resources of limestone. Unique characteristics of coal bottom ash as one of the industrial based pozzolan gained less popularity because of its low reactivity and heavy metal leaching due to conventional method used for disposal. Therefore, an alternative approach was deliberated in this research to utilize coal bottom ash into soluble form and enhance the quality of bottom ash as pozzolanic material. Coal bottom ash after the acid washing with optimum parameter was then undergoes solution-gelification process with various alkali based solution for 2 hours soaking durations. The conversion of coal bottom ash into soluble silica in this study demonstrates good pozzolanic performance in a state of siliceous gel pozzolan compared to the raw ones. 5% of cement replacement by soluble silica from CBA shows good strength development from early and later age. The physical dispersion effect is the cumulative effect of enhancement cement hydration due to the availability of increased the nucleation sites on soluble silica particles.

Tanjung Bin Coal Bottom Ash: From Waste to Concrete Material

2013 ◽  
Vol 705 ◽  
pp. 163-168 ◽  
Author(s):  
Abdulhameed Umar Abubakar ◽  
Khairul Salleh Baharudin
Keyword(s):  
Power Plant ◽  
Economic Value ◽  
Bottom Ash ◽  
Chemical Properties ◽  
Strength Development ◽  
Concrete Material ◽  
Coal Bottom Ash ◽  
Physical And Chemical ◽  
Ash Pond ◽  
And Chemical Properties

Coal Bottom Ash (CBA) is a by-product from the generation of electricity using pulverized coal; Tanjung Bin power plant in Malaysia is a coal-based power plant that generates tonnes of bottom ash daily without known economic value that ends up in the ash pond. Due to the problems associated with the disposal ash pond in terms of cost and environmental impact, attention has now been focused on how best to utilize this waste. This paper present the recent development achieved on the utilization of bottom ash from Tanjung Bin power plant Malaysia in concrete development; physical and chemical properties, workability and fresh concrete properties as well as the strength development of Tanjung Bin bottom ash.

Pozzolanic Reactivity of Coal Bottom Ash after Chemically Pre-Treated with Sulfuric Acid

2019 ◽  
Vol 947 ◽  
pp. 212-216
Author(s):  
Andri Kusbiantoro ◽  
Amalina Hanani ◽  
Rahimah Embong
Keyword(s):  
Construction Industry ◽  
Treatment Process ◽  
Current Trend ◽  
Bottom Ash ◽  
Supplementary Cementitious Materials ◽  
Strength Development ◽  
Coal Bottom Ash ◽  
Cement Replacement ◽  
Pozzolanic Reactivity ◽  
Pre Treatment

Current trend in construction industry has highlighted the use of silica-rich supplementary cementitious materials from industrial wastes in the production of concrete. Numerous studies have validated the pozzolanic properties of these materials, yet coal bottom ash received only infamous reputation as a pozzolanic material, owing to its low reactivity and heavy metals contaminants. Therefore this study was purposed to enhance the pozzolanic reactivity of coal bottom ash through chemical pre-treatment process. Different concentrations of acids and treatment period were studied to obtain optimum parameters for pre-treatment process. Treated ash was characterized for its chemical oxide composition. Its effect on the hydration of cement was studied through the inclusion as cement replacement material in mortar mixtures. From the chemical oxide compositions, a combination of 0.5 M of H2SO4 and 1 hour soaking duration presented the highest SiO2 proportion in the ash. Its inclusion at 5% (by weight of cement) to replace cement proportion in mortar mixtures was able to enhance the compressive strength of mortar at later age, regardless of its slower strength development in the early age. Utilizing treated coal bottom ash as partial cement replacement material has unlocked new achievement for greener future in construction industry.

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