Compressive strength performance of geopolymer paste derived from Completely Decomposed Granite (CDG) and partial fly ash replacement

2017 ◽  
Vol 138 ◽  
pp. 195-203 ◽  
Author(s):  
Jean-Baptiste Mawulé Dassekpo ◽  
Xiaoxiong Zha ◽  
Jiapeng Zhan
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.


Author(s):  
Anıl Niş ◽  
İlhan Altındal

This study investigated the influence of different curing conditions on the compressive strength (CS) of the different alkali activated concrete (AAC) specimens at the ages of 2, 28, and 90 days for the structural utilization and standardization process of AAC instead of OPC concrete. For this aim, 100% slag (S100), 75% slag and 25% fly ash (S75FA25), and 50% slag and 50% fly ash based (S50FA50) AAC specimens were produced. Based on the oven-curing (O), water-curing (W), and ambient-curing (A) methods, the influence of 2O for 2 days, 26A2O, 2O26A, 28A, 28W, 26W2O, and 2O26W for 28 days, and 88A2O, 2O88A, 90A, 88W2O, 2O88W, 90W for 90 days on the CS of the AAC were examined in details. In addition, the influence of delayed oven-curing conditions on CS development was also investigated. The results indicated that curing conditions significantly affected on the CS and the water-curing condition could provide a better CS for those of AAC at 90 days. Although, the oven-curing enhanced CS of the S100 specimens at initial ages (first oven-curing applied), delayed oven-curing (oven-curing applied later) was found significant for S75FA25 and S50FA50 specimens. The delayed oven-curing affected more on the CS of the AAC when fly ash content increased. The most of AAC specimens with oven-curing had significantly enhanced the CS at 28 days, but S50FA50 at the age of 90 days decreased. Different curing regimes were proposed for the superior compressive strength values for each AAC specimens at the ages of 28 and 90 days.


Author(s):  
Madhurima Das ◽  
Siba Prasad Mishra

Coping with population growth, houses are built to meet the hike. The prerequisites for concrete and steel reinforcements have surged up globally since last 3 to 4decades. Shortage of natural building materials, increased wastes from coal based industries to augment carbon foot print has worried the engineers to reuse their wastes (such as fibres, powders, granules, etc.) as building materials ingredient. Glass fibre has improved flexural capabilities with fly ash dosages in cement concrete and alternately helps in restricting environmental degradation. Present research aims at investigating the impact of glass fiber (at 1%, 2% and 3% addition) and fly ash (dosages of 10% and 20% over the existing fly ash in PPC). The ingredients and microstructure of composites are found by either X-ray fluorescent spectroscopy or scanning electron microscope. Experimental evaluation results of the blended composite concrete parameters of RCC are experimentally evaluated and compared have shown that concrete with 10% cement substitution with fly ash and 3% fibre showed optimum compressive strength performance than the concrete without fibre and fly ash and also chemically resistant against commonly used M-20 grade of Concrete.


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.


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