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Cahit Bilim,Okan Karahan,Duran Ati,Serhan lkentapar 대한토목학회 2015 KSCE JOURNAL OF CIVIL ENGINEERING Vol.19 No.3
This paper reports the results of an investigation on the influences of admixtures and curing conditions on some properties ofAlkali-Activated Slag (AAS) mixtures with no cement. In the study, Shrinkage-Reducing (SRA) and superplasticizing and setretarding(WRRe) admixtures were used. For the slag activation, sodium metasilicate was used at two sodium concentrations, 4%and 6% by mass of slag. Setting time, flow loss of fresh mixtures, and shrinkage strain, carbonation, flexural and compressivestrength of hardened mixtures were measured. The test results showed that the admixtures generally had no impact on the settingtimes of AAS pastes. WRRe increased the flow rate of AAS mortars while SRA partially affected the flow values of AAS mortars. This paper reports the results of an investigation on the influences of admixtures and curing conditions on some properties ofAlkali-Activated Slag (AAS) mixtures with no cement. In the study, Shrinkage-Reducing (SRA) and superplasticizing and setretarding(WRRe) admixtures were used. For the slag activation, sodium metasilicate was used at two sodium concentrations, 4%and 6% by mass of slag. Setting time, flow loss of fresh mixtures, and shrinkage strain, carbonation, flexural and compressivestrength of hardened mixtures were measured. The test results showed that the admixtures generally had no impact on the settingtimes of AAS pastes. WRRe increased the flow rate of AAS mortars while SRA partially affected the flow values of AAS mortars. WRRe and SRA did not produce an important difference on the carbonation depths of AAS mortars. However, WRRe and especiallySRA admixtures decreased the shrinkage values of AAS mortars. Additionally, curing conditions had a significant effect on themechanical behavior in the hardened state of AAS mortars compared to Normal Portland Cement (NPC) mortars, and the strengthdevelopment of AAS mortars at early ages was very fast in comparison with NPC mortars when subjected to elevated temperature.
The Effects of Pyrite Ash on the Compressive Strength Properties of Briquettes
Ozlem Celik Sola,Cengiz Duran Atis 대한토목학회 2012 KSCE JOURNAL OF CIVIL ENGINEERING Vol.16 No.7
The aim of this study is to investigate the utilization of Pyrite Ash (PA) in the production of briquettes as a replacement of clay or soil. To achieve this, first, the characterization of the materials used (clayey soil and pyrite ash) was made using Fourier Transform Infrared Spectroscopy (FTIR/ATR). Particle size distribution and microstructure elemental analyses of these materials were also obtained using a particle size analyzer (Mastersizer) and a Scanning Electron Microscope (SEM). Following the characterization of the materials, the samples of briquettes made with or without addition of PA were prepared and sintered at 950 and 1000oC in the furnace. The PA replacement ratios with clayey soil were 0, 5, 10, 20% in mass basis (w/w). Compressive strength and bulk densities of briquettes produced were measured and the results were presented. Compressive strength results of the briquette samples indicated that pyrite ash containing briquettes with 35 MPa compressive strength, which was higher than the requirements of Turkish Standard Specification (TS EN 771-1), can be obtained. It is also recorded that for each mixture, compressive strength values obtained at 1000oC were higher than that of obtained at 950oC. XRD analyze was performed on sintered briquette sample made with 10% PA which have the highest compressive strength value. The XRD results showed that peaks are Quartz (SiO2), Hematite (Fe2O3),Ortoclase (KAlSi3O8), Albite (Na(AlSi3O8)), Anorthite (CaAl2Si2O8) and Gehlenite (2CaO.Al2O3.SiO2).