This research shows the progress of geopolymer synthesis based on high calcium fly ash. In this study, the fly ash contents of 60, 65, and 70 percents by weight and sodium hydroxide solution concentrations of 8 to 12 M were used. Alkali activators for the geopolymer synthesis consisted of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) and the weight ratio of Na2SiO3 to NaOH were 0.50, 1.00, and 1.50. Drying shrinkage deformation of geopolymer paste was investigated by longitudinal measurement in a room temperature. Generally, the drying shrinkage behavior could be divided into three groups. The minimum drying shrinkage strain below 3,000 x 10-6 mm/mm was observed. The results indicated that an increase in the fly ash to alkali solution ratio and the decease of NaOH concentration significantly decreased the drying shrinkage strain. The optimum ratio of Na2SiO3 to NaOH was 1.0. The findings show that high calcium fly ash geopolymer binder could be used for alternative construction materials with low shrinkage strain.
The article presents the study of physical characteristics of warm mix asphalt cement concrete (WMA), components designed by the Marshall Method. Stability, flow rate, strength index, air void, and percent voids in mineral aggregate (VMA) of a total of 77 specimens were examined as a general standard specification test of the Department of Highways, Thailand. Limestone was used as aggregate. Adhesive mixtures of asphalt grade 60/70 were mixed with admixture “ADVERA” to the ratios of 0.20%, 0.25%, and 0.30% by weight of aggregate. WMA-mixing and compaction temperatures were controlled at 115°C, 120°C, and 125°C. The results were that the asphalt cement mixed with 0.25% of ADVERA (by total mixed) at 125°C shows the best mechanical properties standard, with higher value of stability (2,200lbs, i.e., more than the standard 1,800lbs), flow rate, air void, VMA and hardness index. Finally, this study indicates that asphalt concrete added with admixture ADVERA (WMA) could reduce the mixing and compaction temperature during production processes from >160°C to ≤ 125°C.
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