INFLUENCE OF CURING CONDITIONS AND ALKALI HYDROXIDE ON STRENGTH OF FLY ASH GEOPOLYMER CONCRETE

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Khoa Tan Nguyen ◽  
Tuan Anh Le ◽  
An Thao Huynh ◽  
Namshik Ahn
Keyword(s):  
Compressive Strength ◽  
Sodium Hydroxide ◽  
Carbon Dioxide Emissions ◽  
Building Materials ◽  
Sodium Hydroxide Solution ◽  
Curing Temperature ◽  
Geopolymer Concrete ◽  
Curing Time ◽  
Curing Conditions ◽  
Alkali Hydroxide

Geopolymer concrete is known as an alternative to Portland cement, with low carbon dioxide emissions compared with the conventional building materials. In this research, the influence of curing conditions and alkali hydroxide were investigated, using curing temperatures between 40 to 100℃, curing times from 4 to 12 hours, and various types of hydroxide and concentrations of sodium hydroxide solution. Geopolymerization needs energy and time to occur, and higher curing temperatures resulted in larger compressive strength, while longer curing times resulted in higher compressive strength. At the same curing temperature, longer curing time resulted in a higher compressive strength because the longer curing time extends the chemical reaction. For geopolymer concrete, sodium hydroxide is a better property than potassium hydroxide, because the atomic size of sodium anion is smaller than potassium. Further, the strength of concrete increased when the concentration of sodium hydroxide increased. In conclusion, geopolymer concrete is suitable for traditional building materials. Finding renewable materials to satisfy the increasing demand for building structures will be the primary challenge in future.

scholarly journals Effect of Curing Temperature on the Mechanical Strength of Alkali Activated Laterite Geopolymeric Samples

2021 ◽  
Author(s):  
Ahmad Fahmi ◽  
◽  
Alireza Babaeian amini ◽  
Yaser Marabi ◽  
Sohrab Rafati Zavaragh ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Mechanical Strength ◽  
Sodium Hydroxide ◽  
Building Materials ◽  
Sodium Hydroxide Solution ◽  
Low Cost ◽  
High Strength ◽  
Curing Temperature ◽  
Green Materials ◽  
New Type

A huge amount of carbon dioxide is released in the Portland cement production process. A large quantity of greenhouse gases is produced because of the significant amount of energy consumption via making bricks through firing. Using the pozzolanic sources containing the aluminosilicate and alkaline reagents, a new type of green materials called geopolymeric materials are produced with quite lower environmental hazards. The use of laterite as an iron-rich aluminosilicate material has a high potential for building materials. In this study, the effect of the curing temperature and characteristics of the alkaline reagent including the concentration of sodium hydroxide solution and the water-glass to sodium hydroxide mass mixing ratio on the mechanical strength of the laterite-based, oven-cured geopolymer samples was investigated. The results showed that the curing temperature had a significant effect on the compressive strength of the laterite-based geopolymer samples so that with a 15°C change at the curing temperature, the compressive strength of the samples could be multiplied and a sharp increase in the mechanical strength could occur. Also, according to the results of this study, the 6 M sodium hydroxide is recommended for the construction of the laterite-based geopolymer materials with low cost and relatively high strength, and for the construction of higher-strength building materials, the 14 M sodium hydroxide is recommended.

The Effect of Curing Time on the Properties of Fly Ash-Based Geopolymer Bricks

2012 ◽  
Vol 626 ◽  
pp. 937-941 ◽  
Author(s):  
W.I. Wan Mastura ◽  
H. Kamarudin ◽  
I. Khairul Nizar ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
H. Mohammed
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Absorption ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Experimental Work ◽  
Base Material ◽  
Curing Time ◽  
Curing Conditions ◽  
Alkaline Activator

This paper reports the results of an experimental work conducted to investigate the effect of curing conditions on the properties of fly ash-based geopolymer bricks prepared by using fly ash as base material and combination of sodium hydroxide and sodium silicate as alkaline activator. The experiments were conducted by varying the curing time in the range of 1-24 hours respectively. The specimens cured for a period of 24 hours have presented the highest compressive strength for all ratio of fly ash to sand. For increasing curing time improve compressive strength and decreasing water absorption.

Effect of Curing Conditions on the Mechanical Properties of Fly Ash-Based Geopolymer without Sodium Silicate Solution

2014 ◽  
Vol 699 ◽  
pp. 15-19 ◽  
Author(s):  
Rosniza Hanim Abdul Rahim ◽  
Khairun Azizi Azizli ◽  
Zakaria Man ◽  
Muhd Fadhil Nuruddin
Keyword(s):  
Compressive Strength ◽  
Elevated Temperature ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Room Temperature ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Curing Temperature ◽  
Curing Time

Geopolymer is associated with the alkali activation of materials rich in Si and Al, and alkali activator such as sodium hydroxide is used for the dissolution of raw material with the addition of sodium silicate solution to increase the dissolution process. However, the trend of strength development of geopolymer using sodium hydroxide alone is not well established. This paper presents an evaluation on compressive strength of fly ash–based geopolymer by varying curing time with respect to different curing temperature using sodium hydroxide as the only activator. The samples were cured at room temperature and at an elevated temperature (60°C). Further analysis on the microstructure of geopolymer products cured at 60°C was carried out using Field Emission Scanning Microscopy (FESEM). It can be observed that the compressive strength increased as the curing time increased when cured at room temperature; whereas at elevated temperature, the strength increased up to a maximum 65.28 MPa at 14 days but gradually decreased at longer curing time. Better compressive strength can be obtained when the geopolymer was cured at an elevated temperature compared to curing at room temperature.

Mix Design and Compressive Strength of Geopolymer Concrete Containing Blended Ash from Agro-Industrial Wastes

2011 ◽  
Vol 339 ◽  
pp. 452-457 ◽  
Author(s):  
Mohd Azreen Mohd Ariffin ◽  
Mohd Warid Hussin ◽  
Muhammad Aamer Rafique Bhutta
Keyword(s):  
Compressive Strength ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Alkaline Solution ◽  
Sodium Hydroxide Solution ◽  
Mix Design ◽  
Geopolymer Concrete ◽  
Palm Oil Fuel Ash ◽  
Hydroxide Solution ◽  
Fuel Ash

Geopolymer concrete is a type of amorphous alumino-silicate cementitious material. Geopolymer can be polymerized by polycondensation reaction of geopolymeric precursor and alkali polysilicates. Compared to conventional cement concrete, the production of geopolymer concrete has a relative higher strength, excellent volume stability and better durability. This paper presents the mix design and compressive strength of geopolymer concrete manufactured from the blend of palm oil fuel ash (POFA) and pulverized fuel ash (PFA) as full replacement of cement with a combination of sodium silicate and sodium hydroxide solution used as alkaline liquid. The density and strength of the geopolymer concrete with various PFA: POFA ratios of 0:100, 30:70, 50:50 and 70:30 together with sodium silicate to sodium hydroxide solution by mass at 2.5 and 1.0, are investigated. The concentrations of alkaline solution used are 14 Molar and 8 Molar. Tests were carried out on 100x100x100 mm cube geopolymer concrete specimens. Specimens were cured at room temperature and heat curing at 60°C and 90°C for 24 hours, respectively. The effects of mass ratios of PFA: POFA, the alkaline solution to PFA: POFA, ratio and concentration of alkaline solution on fresh and hardened properties of concrete are examined. The results revealed that as PFA: POFA mass ratio increased the workability and compressive strength of geopolymer concrete are increased, the ratio and concentration of alkaline solution increased, the compressive strength of geopolymer concrete increases with regards to curing condition.

Factors Affecting the Compressive Strength of Class C Fly Ash Geopolymer

2011 ◽  
Vol 99-100 ◽  
pp. 960-964 ◽  
Author(s):  
Xue Ying Li ◽  
En Zu Zheng ◽  
Chun Long Ma
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Delay Time ◽  
Curing Temperature ◽  
Mixed Solution ◽  
Mass Ratio ◽  
Curing Conditions ◽  
Factors Affecting ◽  
Class C

The compressive strength of geopolymer prepared from a class C fly ash (CFA) at different curing conditions and mass ratio of water to fly ash were investigated. The geopolymer was activated with a mixed solution of sodium hydroxide (NaOH) and sodium silicate. The results revealed that the obtained compressive strength was in the range of 11.7~61.9MPa and the compressive strength decreased with the increment of the mass ratio of water to CFA (W/F). The geopolymer samples with the highest strength were obtained when W/F was 0.30 with proper delay time 1d before being demoulded and then followed by curing at 60°C for 24h. For geopolymer with lower W/F (0.30), its optimum curing temperature was better not higher than 60°C, however, for the higher W/F, the curing temperature was suit to more than 70°C.

scholarly journals Compressive Strength of Geopolymer Concrete Composites: Modeling and Comprehensive Systematic Review

2021 ◽  
Author(s):  
Hemn Unis Ahmed ◽  
Azad A. Mohammed ◽  
Ahmed S. Mohammed
Keyword(s):  
Systematic Review ◽  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Alkaline Solution ◽  
Construction Material ◽  
Assessment Tools ◽  
Curing Temperature ◽  
Geopolymer Concrete

Abstract The growing concern about global climate change and its adverse impacts on societies is putting severe pressure on the construction industry as one of the largest producers of greenhouse gases. Given the environmental issues associated with cement production, geopolymer concrete has emerged as a sustainable construction material. Geopolymer concrete is cementless concrete that uses industrial or agro by-product ashes as the main binder instead of ordinary Portland cement; this leads to being an eco-efficient and environmentally friendly construction material. Compressive strength is one of the most important mechanical property for all types of concrete composites including geopolymer concrete, and it is affected by several parameters like an alkaline solution to binder ratio (l/b), fly ash (FA) content, SiO2/Al2O3 (Si/Al) of the FA, fine aggregate (F) and coarse aggregate (C) content, sodium hydroxide (SH) and sodium silicate (SS) content, ratio of sodium silicate to sodium hydroxide (SS/SH), molarity (M), curing temperature (T), curing duration (CD) inside the oven and specimen ages (A). In this regard, a comprehensive systematic review was carried out to show the effect of these different parameters on the compressive strength of the fly ash-based geopolymer concrete (FA-GPC). In addition, multi-scale models such as Artificial Neural Network (ANN), M5P-tree (M5P), Linear Regression (LR), and Multi-logistic Regression (MLR) models were developed to predict the compressive strength of FA-GPC composites. For the first time, in the modeling process, twelve effective parameters including l/b, FA, Si/Al, F, C, SH, SS, SS/SH, M, T, CD, and A were considered the modeling input parameters. Then, the efficiency of the developed models was assessed by various statistical assessment tools like Root Mean Squared Error (RMSE), Mean Absolute Error (MAE), Scatter Index (SI), OBJ value, and the Coefficient of determination (R2). Results show that the curing temperature, sodium silicate content, and ratio of the alkaline solution to the binder content are the most significant independent parameters that influence on the compressive strength of the FA-GPC, and the ANN model has better performance for predicting the compressive strength of FA-GPC in compared to the other developed models.

scholarly journals Compressive Strength of Fly ash-based Geopolymer Concrete with a Variable of Sodium Hydroxide (NaOH) Solution Molarity

2018 ◽  
Vol 147 ◽  
pp. 01004 ◽  
Author(s):  
Herwani ◽  
Ivindra Pane ◽  
Iswandi Imran ◽  
Bambang Budiono
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Raw Materials ◽  
Sodium Hydroxide Solution ◽  
Solution Concentration ◽  
Geopolymer Concrete ◽  
Hydroxide Solution ◽  
Naoh Solution ◽  
New Material

Geopolymer concrete is a new material made by activating the raw materials which contain many elements of silica and alumina. Compressive strength of geopolymer concrete produced was influenced by the concentration of the activator solution. This paper presents an experimental investigation into fly ash-based geopolymer concrete. Research objective was to investigate the effects of alkaline activator solution (AAS) molarity on compressive strength of geopolymer concrete. Variable of the test were a solution to sodium hydroxide was chosen as the activator solution. Concentration of sodium hydroxide solution used was 10 M, 12 M and 14 M with ambient curing. The specimen is made of concrete cylinder with diameter 10 cm and height 20 cm as many as 9 pieces each variable. Compressive strength tests is performed when the concrete is 7, 14, and 28 days old. Results of the test are indicated that the increasing of sodium hydroxide (NaOH) solution concentration leads to improve the compressive strength of geopolymer concrete. The optimal compressive strength of geopolymer concrete was achieved at a concentration of sodium hydroxide solution (NaOH) of 12 M. Geopolymer concretes compressive strength only achieves around 50-60% of the planned.

Research on Mechanical Properties of Geopolymer Concrete under early Stage Curing System

2012 ◽  
Vol 164 ◽  
pp. 492-496
Author(s):  
Qing Wang ◽  
Kun Ran ◽  
Zhao Yang Ding ◽  
Lin Ge Qiu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Room Temperature ◽  
Storage Time ◽  
Early Stage ◽  
Curing Temperature ◽  
Geopolymer Concrete ◽  
Curing Time ◽  
Curing Age

Mechanical properties of geopolymer concrete under early stage curing system were studied. The results showed that at the early stage of curing time, compressive strength was improved significantly with the increasing of curing temperature and curing time. The compressive strength decreased and was close to that of standard curing condition at the age of 28d as the curing age increased. In addition, prolonging the storage time at room temperature before the step of high temperature curing could increase the long-term strength.

scholarly journals Effect of Polypropylene fibers over GGBS based Geopolymer Concrete Under Ambient Curing

2019 ◽  
Vol 9 (2S2) ◽  
pp. 89-92 ◽  
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Sodium Hydroxide Solution ◽  
Strength Test ◽  
Polypropylene Fibers ◽  
Geopolymer Concrete ◽  
Split Tensile Strength ◽  
Curing Conditions ◽  
The Matrix ◽  
Ambient Curing

Geopolymer is being widely used in the construction industry in the recent years. Ground Granulated Blast Furnace Slag (GGBS) based geopolymer concrete is the most suited for ambient curing conditions. It has been perceived that geopolymer concrete is brittle in nature. This brittleness could be reduced by the augmentation of fibers. The objective of this paper is to study the effect of incorporation of polypropylene fibers in Geopolymer Concrete. The various proportions of the ingredients of Geopolymer concrete were calculated from the B.V.Rangan mix design of Geopolymer Concrete. Based on the previous research works conducted by the author, optimum molarity of the sodium hydroxide solution to be used as a part of alkaline activator solution was taken as 13M. Polypropylene fibers were added to the matrix in the ratios from 0.1% to 0.6%. Cubical, Cylindrical and Prism Specimens were casted and subjected to ambient curing. Compaction factor test was performed to measure workability of fresh concrete and tests such as compressive strength test, split tensile strength test and flexural strength test were performed to assess the mechanical properties of hardened Fiber Reinforced Geopolymer Concrete. Tests were carried after curing period of 7days & 28 days and the results were tabulated. Being a low modulus fiber, the fiberposses a good post cracking behaviour and reduce the brittleness of the Geopolymer Concrete. The incorporation of polypropylene fibers increases the compressive strength and flexural strength initially and then decreases.

scholarly journals Compressive Strength of Sustainable Geopolymer Concrete Composites: A State-of-the-Art Review

2021 ◽  
Vol 13 (24) ◽  
pp. 13502
Author(s):  
Hemn Unis Ahmed ◽  
Azad A. Mohammed ◽  
Serwan Rafiq ◽  
Ahmed S. Mohammed ◽  
Amir Mosavi ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Construction Material ◽  
Curing Temperature ◽  
Geopolymer Concrete ◽  
Palm Oil Fuel Ash ◽  
Silicate Content ◽  
Binder Ratio

The building industry, which emits a significant quantity of greenhouse gases, is under tremendous pressure due to global climate change and its consequences for communities. Given the environmental issues associated with cement production, geopolymer concrete has emerged as a sustainable construction material. Geopolymer concrete is an eco-friendly construction material that uses industrial or agricultural by-product ashes as the principal binder instead of Portland cement. Fly ash, ground granulated blast furnace slag, rice husk ash, metakaolin, and palm oil fuel ash were all employed as binders in geopolymer concrete, with fly ash being the most frequent. The most important engineering property for all types of concrete composites, including geopolymer concrete, is the compressive strength. It is influenced by different parameters such as the chemical composition of the binder materials, alkaline liquid to binder ratio, extra water content, superplasticizers dosages, binder content, fine and coarse aggregate content, sodium hydroxide and sodium silicate content, the ratio of sodium silicate to sodium hydroxide, the concentration of sodium hydroxide (molarity), curing temperature, curing durations inside oven, and specimen ages. In order to demonstrate the effects of these varied parameters on the compressive strength of the fly ash-based geopolymer concrete, a comprehensive dataset of 800 samples was gathered and analyzed. According to the findings, the curing temperature, sodium silicate content, and alkaline solution to binder ratio are the most significant independent parameters influencing the compressive strength of the fly ash-based geopolymer concrete (FA-BGPC) composites.

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