scholarly journals An Attempt to Reduce Materials Cost of Autoclaved Aerated Concrete Production

2016 ◽  
Vol 10 (1) ◽  
pp. 323-333 ◽  
Author(s):  
Zhijuan Wang ◽  
Yuanming Song ◽  
Baoling Li

Background: Municipal solid waste incineration (MSWI) bottom ash contains a not insignificant amount of metallic aluminum, while circulating fluidized bed combustion (CFBC) fly ash is rich in active SiO2. Objective: To reduce the materials cost of autoclaved aerated concrete (AAC) production, these two types of solid waste could theoretically be used as the aerating agent and silica source, respectively. Method: In the present work, the metallic aluminum concentration in an MSWI bottom ash sample was determined from hydrogen generation and this ash was used to make AAC in conjunction with CFBC fly ash. The extent of air entrainment in the resulting AAC specimens was varied by changing the bottom ash to fly ash ratio, and the effects of this ratio on the properties of the AAC were investigated. Results: Results showed that the ratio has a negligible effect on both the type and the morphology of the hydrates in the AAC, but is inversely proportional to the compressive strength, density and volume stability. Conclusion: This study proves that AAC having satisfactory properties can be successfully prepared from a combination of MSWI bottom ash and CFBC fly ash.

2015 ◽  
Vol 650 ◽  
pp. 51-70 ◽  
Author(s):  
En Hua Yang ◽  
Yi Quan Liu ◽  
Zhi Tao Chen

Municipal solid waste incineration bottom ash (IBA) has great potential to be utilized for civil engineering applications. This paper is to investigate the characteristic of gas generation from IBA and to study the potential of IBA as aerating agent to replace costly aluminum powder and as silica source to partially replace silica flour/fly ash in the production of autoclaved aerated concrete (AAC). Results show the aeration capacity of IBA used in this study is about 1% that of pure aluminum powder by mass. Finer particles, higher alkali molarity, and higher reaction temperature encourage the reaction and more gas is generated per gram of IBA. Type of alkaline solution does not seem to be an important factor for gas generation from IBA. Several exemplary lightweight mortars and AACs were produced by incorporating IBA as aerating agent. It is highly plausible IBA can be used as aerating agent to replace pure aluminum powder in the production of normal aerated concrete. IBA-AACs with density ranging from 600 to 800 kg/m3 were successfully synthesized by using IBA as aerating agent. For a given density, the compressive strength of IBA-AAC is higher than that of AAC due to the formation of more uniform pore structure with smaller pore size in IBA-AAC.


2020 ◽  
Vol 11 (1) ◽  
pp. 107
Author(s):  
B. Simões ◽  
P. R. da Silva ◽  
R. V. Silva ◽  
Y. Avila ◽  
J. A. Forero

This study aims to evaluate the potential of incorporating fly ash (FA) and municipal solid waste incinerator bottom ash (MIBA) as a partial substitute of cement in the production of self-compacting concrete mixes through an experimental campaign in which four replacement levels (i.e., 10% FA + 20% MIBA, 20% FA + 10% MIBA, 20% FA + 40% MIBA and 40% FA + 20% MIBA, apart from the reference concrete) were considered. Compressive and tensile strengths, Young’s modulus, ultra-sonic pulse velocity, shrinkage, water absorption by immersion, chloride diffusion coefficient and electrical resistivity were evaluated for all concrete mixes. The results showed a considerable decline in both mechanical and durability-related performances of self-compacting concrete with 60% of substitution by MIBA mainly due to the aluminium corrosion chemical reaction. However, workability properties were not significantly affected, exhibiting values similar to those of the control mix.


ce/papers ◽  
2018 ◽  
Vol 2 (4) ◽  
pp. 47-51 ◽  
Author(s):  
Bernd Winkels ◽  
Holger Nebel ◽  
Michael Raupach

RSC Advances ◽  
2018 ◽  
Vol 8 (67) ◽  
pp. 38701-38705
Author(s):  
Qingna Kong ◽  
Jun Yao ◽  
Qian Yang ◽  
Dongshen Shen ◽  
Yuyang Long

A new approach including weathering treatment and nano-silica filling was employed to promote the engineering properties of municipal solid waste incinerator (MSWI) bottom ash.


2020 ◽  
Vol 10 (17) ◽  
pp. 6075
Author(s):  
Ahmad Assi ◽  
Fabjola Bilo ◽  
Alessandra Zanoletti ◽  
Laura Borgese ◽  
Laura Eleonora Depero ◽  
...  

This study presents an innovative stabilization method of fly ash derived from co-combustion of municipal solid waste and sewage sludge. Bottom ash, obtained from the same process, is used as a stabilizing agent. The stabilization method involved the use of two other components—flue gas desulfurization residues and coal fly ash. Leaching tests were performed on stabilized samples, aged in a laboratory at different times. The results reveal the reduction of the concentrations of heavy metals, particularly Zn and Pb about two orders of magnitude lower with respect to fly ash. The immobilization of heavy metals on the solid material mainly depends on three factors—the amount of used ash, the concentrations of Zn and Pb in as-received fly ash and the pH of the solution of the final materials. The inert powder, obtained after the stabilization, is a new eco-material, that is promising to be used as filler in new sustainable composite materials.


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