An investigation of some alternative aggregates for use in concrete

Author(s):  
A. K. Butler ◽  
A. M. Harrisson

AbstractThe use of some waste materials as aggregate for concrete has been investigated. Three specific materials were examined, china clay waste, slate waste and pulverized fuel ash. The project investigated methods of utilising alternative materials as aggregate either by low cost processing, novel mix design or by the use of admixtures.

2014 ◽  
Vol 548-549 ◽  
pp. 111-117
Author(s):  
M.S. Shakri ◽  
M.A. Hafez ◽  
M.A. Adnan

Pulverized fuel ash (PFA) can be classified as hazardous Coal Combustion by-Product (CCP), which can contributes to the environmental pollution. According to (ACAA 2009), USA itself has produced approximately 125.5 million tons per annual of CCP which merely 56 million tons of these waste by-products has been successfully employed in applications and others still remain untreated. Disposal of these materials in landfills can deduce ecological. Thus, finding the solutions and methods of recycling these waste materials are needed, as it can be used as one of the materials in construction projects, engineering purpose or stabilizing process. Therefore, a study on direct shear test have been conducted and the data collected from this study were compared and analyzed through various methods to find out how does PFA works on improving geotechnical properties.


2016 ◽  
Vol 709 ◽  
pp. 61-65 ◽  
Author(s):  
Ting Ting Zhang ◽  
Yan Nan Du ◽  
Yan Jie Sun ◽  
Zi Ming He ◽  
Zhen Lin Wu

Magnesium silicate hydrate (M-S-H) gel can be fabricated via the reaction of MgO with silica fume in the presence of sodium hexametaphosphate (Na-HMP). In this study, in effort to reduce the cost of the M-S-H gel system, pulverized fuel ash (PFA) was utilized as a silica source to replace silica fume. The influence of various PFA quantities on the compression strength and other properties of the M-S-H system were investigated via XRD, SEM, and TG-RTG analysis. Compressive strength was optimal when 35 wt% of silica fume was replaced. The hydration products were relatively more complex when PFA was used, containing hydrated calcium silicate, hydrated magnesium silicate, and carbonate gel, among other products. Magnesium carbonate participated in the hydration reaction process, which generated carbonated gel to form a grid structure and promoted the initial strength of the material. Taken together, the results showed that PFA can be feasibly and effectively used to form M-S-H gel cement systems at low cost.


2019 ◽  
Vol 46 (6) ◽  
pp. 522-533
Author(s):  
Yasmin Murad ◽  
Yousef Abu-Haniyi ◽  
Ala AlKaraki ◽  
Zeid Hamadeh

A series of cyclic tests on unconfined beam–column connections with composite concrete materials are conducted. Cement is partially replaced by waste materials using two different percentages of 15% and 20%. The proper percentage of cement replacement is found to be 15% for the pulverized fuel ash, silica fume, and iron filings. Increasing the percentage to 20% tends to relatively decrease concrete compressive strength, weaken the joint, and reduce its ductility. It is recommended using pulverized fuel ash to enhance the performance of beam–column connections under cyclic loading. Silica fume and iron filings have also enhanced the joint response, but the enhancement is most remarkable when using 15% pulverized fuel ash. The implementation of composite concrete has increased the joint’s ductility and reduced its level of damage based on the type and percentage of the implemented waste material. Furthermore, the disposal of waste materials into the concrete mix is a good solution for reducing environmental pollution.


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