scholarly journals Experimental Investigation on Compressive Strength Enhancement of Geopolymer Paste Fly Ash/ Slag Based Cured at Ambient Condition

2020 ◽  
Vol 13 (2) ◽  
pp. 87-92
Author(s):  
Wrood H. Sachet ◽  
◽  
Wissam D. Salman ◽  
Safie Mahdi Oleiwi ◽  
Dia Eddin Nassani
Author(s):  
A. Z. Mohd Ali ◽  
◽  
N. A. Jalaluddin ◽  
N. Zulkiflee ◽  
◽  
...  

The production of ordinary Portland cement (OPC) consumes considerable amount of natural resources, energy and at the same time contribute in high emission of CO2 to the atmosphere. A new material replacing cement as binder called geopolymer is alkali-activated concrete which are made from fly ash, sodium silicate and sodium hydroxide (NaOH). The alkaline solution mixed with fly ash producing alternative binder to OPC binder in concrete named geopolymer paste. In the process, NaOH was fully dissolved in water and cooled to room temperature. This study aims to eliminate this process by using NaOH in solid form together with fly ash before sodium silicate liquid and water poured into the mixture. The amount of NaOH solids were based on 10M concentration. The workability test is in accordance to ASTM C230. Fifty cubic mm of the geopolymer paste were prepared which consists of fly ash to alkaline solution ratio of 1: 0.5 and the curing regime of 80℃ for 24 hours with 100% humidity were implemented. From laboratory test, the workability of dry method geopolymer paste were decreased. The compressive strength of the dry mix of NaOH showed 55% and the workability has dropped to 58.4%, it showed strength reduction compared to the wet mix method.


Author(s):  
I N Guntur ◽  
M W Tjaronge ◽  
R Irmawaty ◽  
J J Ekaputri

Author(s):  
B A Affandhie ◽  
P T Kurniasari ◽  
M S Darmawan ◽  
S Subekti ◽  
B Wibowo ◽  
...  

2018 ◽  
Vol 195 ◽  
pp. 01023 ◽  
Author(s):  
Ari Widayanti ◽  
Ria Asih Aryani Soemitro ◽  
Hitapriya Suprayitno ◽  
Januarti Jaya Ekaputri

Fly ash is a by-product obtained from coal combustion process. Some of the utilization of fly ash is to produce geopolymer products which have high compressive strength, fire, chemical resistance. This paper proposes fly ash from unit 1-7 Suralaya Power Plant Indonesia. The aims of this study are to obtain characterization of fly ash and mechanical properties of geopolymer paste based on variations of the alkali activator ratio. The method was based on previous research and laboratory investigation. XRF and compressive strength were analysed in this study. Alkali activator was obtained from NaOH and Na2SiO3 mixture. The ratio of Na2SiO3 to NaOH was in the range of 0.5-2.5. Geopolymer paste was casted in acrylic cylinders with a diameter of 2 cm and a height of 4 cm. The curing was conducted at room temperature until the day for the compressive strength test at 28 days. The result showed that the fly ash is classified as F class. Increasing the alkali activator ratio influenced the strength. The best composition of geopolymer paste is made with NaOH 8M, and the mass ratio of Na2SiO3 to NaOH is 2.5. This composition produced compressive strength of 98.6 MPa.


In this paper, compressive strength (CS) of geopolymer paste has been studied under ambient conditions using locally available Class C fly ash, GGBFS and silica fume and a combination alkali activator, namely: NaOH and Na2SiO3 . Two approaches were used for mix proportioning and 60 mixes of the paste were proportioned. It is found that all the mixes proportioned were workable and no adverse effects were observed within 30 minutes of mixing. It is found that the ‘minimum voids’ approach along with a constant fly ash – to – activator ratio (FA/AA) is the best approach for the design of geopolymer mixes, rather than a constant water- to- solid ratio (w/s). Further, the role of GGBFS and SF on the CS of the paste has also been highlighted.


Flyash is one of the largest emerging products in the construction industry. The fly ash is the by-product which is widely used in brick manufacturing plant. The flyash reduces the cement content and also overcomes several disadvantages. Simply, it is a step towards eco-friendly environment. Though the flyash brick has many advantages, it has lower strength at initial stages due to low hydration. In this study, the experimental investigation was carried out to find the optimum mix ratio of various compositions of fly ash bricks. The brick specimens were casted on different compositions of cement, flyash, eco-sand and various other admixtures. On addition of these admixtures the early compressive strength was also high and a quick hydration was observed. The tests were conducted on 3rd, 5th, 7th and 28th day. The results suggest that the maximum strength was obtained for the composition of fly ash, ecosand, cement and silica fume.


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