Mechanical Properties of Non-cement Matrix according to mixing method Circulating fluidized bed combustion boiler fly ash and based on Blast furnace slag and Polysilicon

Author(s):  
Jin-Hyun Shin ◽  
◽  
Sang-Soo Lee ◽  
Tae-Hyun Kim ◽  
◽  
...  

we have experimented to reduce fine dust which is a problem in the world. Fine dust is known to cause various diseases in the human body. Diatomite with adsorption characteristics was used to reduce fine dust, which is a source of indoor air pollution. As a binder, blast furnace slag and a circulating fluidized bed combustion boiler fly ash were used to replace cement. The assessment items are flexural strength, compressive strength, flow ability, density, water absorption, fine dust concentration. As the replacement ratio of diatomite increases, the density decreases and the water absorption tends to increase. It is considered that this is due to the porous property of diatomite. Flowability decreased with increasing diatomite replacement ratio. As the replacement ratio of diatomite increased, the amount of air content to increase. As the replacement ratio of diatomite increased, the adsorption performance per minute of fine dust increased. This is because the amount of fine dust adsorbed per specific surface area increased as the replacement ratio of diatomite having porous properties increased. If additional experiments are done and used for finishing materials, it will contribute to the improvement of indoor air quality.


2018 ◽  
Vol 149 ◽  
pp. 01012 ◽  
Author(s):  
Leonid Dvorkin ◽  
Nataliya Lushnikova ◽  
Mohammed Sonebi

The increase of the consumption of gypsum products in construction industry with a limited amount of natural gypsum deposits requires alternative sources of gypsum-containing raw materials. In some countries which have fertilizers industry plants, the problem can be solved using industrial wastes, e.g. phosphorgypsum – a byproduct of fertilizers’ production. Kept in dumps over decades, phosphorgypsum is subjected to the chemical changes due to washing out impurities with rain and other natural factors. However, there are observed deviations of harmful impurities in dumped PG depending on its age., Phosphorgypsum of any age requires chemical treatment to neutralize remains of phosphorus and sulfuric acids, fluorine compounds. According to our researches one of the most simple and effective method of neutralization the impurities is using lime-containing admixtures. The paper presents results of laboratory tests of phosphorgypsum as a component of clinker and non-clinker binders. There were investigated the impact of phosphorgypsum as admixture for clinker binders to substitute natural gypsum. Neutralized phosphorgypsum can be applied as mineralizing admixture in calcination of Portland cement clinker. Adding 2 to 2.5% of phosphorgypsum as setting time regulator resulted in a similar physical and mechanical properties compared to mix made with natural gypsum. Another important area of phosphorgypsum application is sulphate activatoion of low-clinker blast-furnace slag cement (clinker content is less than 19%). According to results, the incorporation of phosphorgypsum as sulphate activator in cement has the better effect as natural gypsum. Other development has been carried out to modify the phosphorgypsum binder properties. Complex additive consisted of polycarboxylate-based superplasticizer and slaked lime permitted an increase mechanical properties of hardened phosphorgypsum binder due to significant a reduction of water consumption. Such modified binder can be used as partial or complete replacement of gypsum binder for filling cements and finishing plasters. It can substitute gypsum in non-clinker binders like supersulphated cements. There were also developed compositions of supersulphated cements based on low-alumina blast furnace slag and phosphorgypsum. Supersulphated cements were tested in normal-weight and light-weight concrete.


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