Showing papers by "Januarti Jaya Ekaputri published in 2020"

Effect of embedment length on bond strength of geopolymer concrete

Abstract: The evaluation of the pull-out experimental result of the steel reinforcing bar on fly ash-based geopolymer concrete prism is presented in this study. A single reinforcing bar with the nominal diameter (db) of 13mm was pulled out from the geopolymer concrete prism. Three sizes of geopolymer concrete prism were presented, 100×100×200, 150×150×200, and 180×180×200 m3. Hence the ratio of cover thickness to diameter of the bar (c/db) were 3.4, 5.4, and 6.6. The effects of embedment length (Ld) that were 3db, 5db, and 7db were investigated. The results showed that the embedment length changed the mode of failure. The pull-out failure occurred on the specimens with the short embedment length (3db), splitting failure occurred on the long embedment length, and the bar ruptured on the large specimens with longer embedment length (7db). The highest of maximum pull-out load and the bond strength obtained were 77.58 kN and 42.13 MPa, respectively. The maximum pull-out load increased with increasing the embedment length. The bond strength decreased as the embedment length increased.

Compressive strength of medium calcium fly ash based geopolymer paste

Abstract: This study discusses the effect of heating duration and curing age on compressive strength geopolymer paste made with medium calcium fly ash and potassium hydroxide solution (KOH). The hardening process was performed in an oven at a temperature of 100 ± 5°C in a variety of heating duration for 2, 4, and 6 hours to form a geopolymer paste with a potassium hydroxide concentration of 6 M. Flow testing on fresh paste indicatesd that all materials was bond properly without segregation. After the heating process in the oven, the spesimens were cured at room temperature until the age of 3, 7, and 28 days. The results of the compressive tests indicated that the heating duration and curing age were the key factors. Where there is no visible negative effect of the medium level CaO content in fly ash against compressive strength development of the hardened geopolymer paste.