scholarly journals Influence of the Composition of the Activator on Mechanical Characteristics of a Geopolymer

2020 ◽  
Vol 10 (10) ◽  
pp. 3349 ◽  
Author(s):  
Adelino V. Lopes ◽  
Sergio M.R. Lopes ◽  
Isabel Pinto
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Carbon Dioxide Emissions ◽  
Sustainable Construction ◽  
Low Carbon ◽  
High Durability ◽  
Strength Tests

Geopolymer materials are characterized by their high durability and low carbon dioxide emissions, when compared with more traditional materials, like concrete made from ordinary Portland cement. These are interesting advantages and might lead to a more sustainable construction industry. The aim of this study is the characterization of the mechanical behavior of the materials obtained by the activation of metakaolin. The activator is a mixture of sodium hydroxide with sodium silicate in different proportions. The influence of the composition of activator is studied. For the analysis of the mechanical properties of the different mixtures two different types of tests were performed, bending tensile strength tests and compressive strength tests. The results show that an activator with not less than 300 g of sodium hydroxide and not exceeding 600 g of sodium silicate per 750 g of metakaolin gives the best results, for both tensile strength and compressive strength.

Flood Mud as Geopolymer Precursor Materials: Effect of Curing Regime on Compressive Strength

2015 ◽  
Vol 815 ◽  
pp. 177-181 ◽  
Author(s):  
Mohd Mustafa Al Bakri Abdullah ◽  
Mukridz Md Mohtar ◽  
Liew Yun Ming ◽  
Muhammad Faheem Mohd Tahir ◽  
Kamarudin Husin ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Strength Properties ◽  
Sem Analysis ◽  
Raw Material ◽  
Curing Temperature ◽  
Strength Tests ◽  
Maximum Compressive Strength ◽  
Curing Regime

This paper studies the effect of curing temperature and curing duration to the flood mud based geopolymer on compressive strength properties. Flood mud was used as a raw material for geopolymer and geopolymer samples were synthesized by using sodium silicate and sodium hydroxide 14M solution. These samples were cured at different temperature (100°C, 150°C, 200°C and 250°) for different curing duration (6h, 12h and 24h) respectively. Compressive strength tests were carried out at after 28 days. The compressive strength and SEM analysis of geopolymer products were evaluated. Result showed that the maximum compressive strength was 24 MPa at temperature of 150°C for 24 hours. With increasing ageing day, densification of geopolymer gel was observed.

Characterization of Fly Ash on Geopolymer Paste

2016 ◽  
Vol 841 ◽  
pp. 118-125 ◽  
Author(s):  
Ratni Nurwidayati ◽  
Muhammad Bahrul Ulum ◽  
Januarti Jaya Ekaputri ◽  
Triwulan ◽  
Priyo Suprobo
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Specific Surface ◽  
Sodium Hydroxide ◽  
Surface Area ◽  
Sodium Silicate ◽  
Specific Surface Area ◽  
Different Sources ◽  
Geopolymer Paste

The effect of loss of ignition, specific gravity, fineness, specific surface area and soluble fly ash to compressive strength of geopolymer paste were studied. Six fly ashes from two different sources and different time of collection were evaluated. Sodium hydroxide and sodium silicate were used as alkali activator. Concentration of sodium hydroxide and mass ratio of sodium hydroxide to sodium silicate were fixed 14M and one respectively. The result indicated that the improvement in compressive strength of geopolymer paste was more influenced by fineness, specific surface area and soluble content of fly ash. Soluble content of fly ash greatly affected the compressive strength of geopolymer paste compare to the compressive strength of cement paste with 20% fly ash replacement.

The Effect of Dry Mix Sodium Hydroxide onto Workability and Compressive Strength of Geopolymer Paste

2020 ◽  
Vol 12 (9) ◽  
Author(s):  
A. Z. Mohd Ali ◽  
◽  
N. A. Jalaluddin ◽  
N. Zulkiflee ◽  
◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Alkaline Solution ◽  
High Emission ◽  
New Material ◽  
Curing Regime ◽  
Solid Form ◽  
Geopolymer Paste

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.

scholarly journals Assessment of the mechanical properties of glass ionomer cements for orthodontic cementation

2012 ◽  
Vol 17 (6) ◽  
pp. 154-159 ◽  
Author(s):  
Marcel M. Farret ◽  
Eduardo Martinelli de Lima ◽  
Eduardo Gonçalves Mota ◽  
Hugo Mitsuo S. Oshima ◽  
Gabriela Maguilnik ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Glass Ionomer Cements ◽  
Glass Ionomer ◽  
Resin Modified Glass Ionomer ◽  
Strength Tests ◽  
Diametral Tensile Strength

OBJECTIVE: To evaluate the mechanical properties of three glass ionomers cements (GICs) used for band cementation in Orthodontics. METHODS: Two conventional glass ionomers (Ketac Cem Easy mix/3M-ESPE and Meron/Voco) and one resin modified glass ionomer (Multi-cure Glass ionomer/3M-Unitek) were selected. For the compressive strength and diametral tensile strength tests, 12 specimens were made of each material. For the microhardness test 15 specimens were made of each material and for the shear bond strength tests 45 bovine permanent incisors were used mounted in a self-cure acrylic resin. Then, band segments with a welded bracket were cemented on the buccal surface of the crowns. For the mechanical tests of compressive and diametral tensile strength and shear bond strength a universal testing machine was used with a crosshead speed of 1,0 mm/min and for the Vickers microhardness analysis tests a Microdurometer was used with 200 g of load during 15 seconds. The results were submitted to statistical analysis through ANOVA complemented by Tukey's test at a significance level of 5%. RESULTS: The results shown that the Multi-Cure Glass Ionomer presented higher diametral tensile strength (p < 0.01) and compressive strength greater than conventional GICs (p = 0.08). Moreover, Ketac Cem showed significant less microhardness (p < 0.01). CONCLUSION: The resin-modified glass ionomer cement showed high mechanical properties, compared to the conventional glass ionomer cements, which had few differences between them.

Physical, Mechanical and Micro-Structural Properties of F Type Fly-Ash Based Geopolymeric Bricks Produced by Pressure Forming Process

2010 ◽  
Vol 69 ◽  
pp. 69-74 ◽  
Author(s):  
Ömer Arıöz ◽  
Kadir Kilinç ◽  
Mustafa Tuncan ◽  
Ahmet Tuncan ◽  
Taner Kavas
Keyword(s):  
Heat Treatment ◽  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Heat Treatment Temperature ◽  
Treatment Duration ◽  
Treatment Temperature ◽  
Alumino Silicate ◽  
Heat Treatment Duration

Geopolymer is a new class of three-dimensionally networked amorphous to semi-crystalline alumino-silicate materials, and first developed by Professor Joseph Davidovits in 1978. Geopolymers can be synthesized by mixing alumino–silicate reactive materials such as kaolin, metakaolin or pozzolans in strong alkaline solutions such as NaOH and KOH and then cured at room temperature. Heat treatment applied at higher temperatures may give better results. Depending on the mixture, the optimum temperature and duration vary 40-100 °C and 2-72 hours, respectively. The properties of geopolymeric paste depend on type of source material (fly ash, metakaolin, kaolin), type of activator (sodium silicate-sodium hydroxide, sodium silicate-potassium hydroxide), amount of activator, heat treatment temperature, and heat treatment duration. In this experimental investigation, geopolymeric bricks were produced by using F-type fly ash, sodium silicate, and sodium hydroxide solution. The bricks were treated at various temperatures for different hours. The compressive strength and density of F-type fly ash based geopolymeric bricks were determined at the ages of 7, 28 and 90 days. Test results have revealed that the compressive strength values of F-type fly ash based geobricks ranged between 5 and 60 MPa. It has been found that the effect of heat treatment temperature and heat treatment duration on the density of F-type fly ash based geobricks was not significant. It should be noted that the spherical particle size increased as the heat treatment temperature increased in the microstructure of F-type fly ash based geobricks treated in oven at the temperature of 60 °C for 24 hours.

scholarly journals Geopolymer Stabilisation of Unfired Earth Masonry Units

2014 ◽  
Vol 600 ◽  
pp. 175-185 ◽  
Author(s):  
Daniel Maskell ◽  
Andrew Heath ◽  
Pete Walker
Keyword(s):  
Compressive Strength ◽  
Moisture Content ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Large Scale ◽  
High Moisture Content ◽  
High Moisture ◽  
Load Bearing ◽  
Disproportionate Collapse ◽  
Masonry Units

Contemporary domestic structures typically use masonry units that are approximately 100mm thick. There is interest in using commercial methods of manufacture to produce earthen bricks that have a similar form factor to conventional masonry The large scale adoption of thin walled unfired earth masonry is dependent on its suitability for use in a load bearing application. High moisture content leading to full saturation, for example as a result of flooding, is a concern for unstablised earth construction, especially as wall thickness reduces. The greatest barrier for earth masonry adoption is the durability of the material when affected by high moisture content. Accidental and intentional wetting of a 100mm thick load bearing unfired earth wall could lead to disproportionate collapse. The paper presents initial findings from an investigation into the use of geopolymer mechanism as a method of stabilisation. The use of geopolymer mechanism was chosen as a possible method of improving the water resilience. Soil that is used for commercial extruded fired brick production was chosen. The soil was selected as the precursor (source of the required silica and alumina) and this was mixed with various sodium hydroxide and sodium silicate activators. Specimens were tested both in their dry sate as well as following 24 hours of submersion in water. Compressive strength of cylinders after saturation, was used as an indicator of effective stabilisation. The maximum dry compressive strength achieved was 10.4N/mm2 with the addition of 5% sodium hydroxide and 20% sodium silicate after curing at 105°C. The most significant contributor to the strength gain was the addition of sodium silicate. Although some of the cylinders were able to be tested under fully saturated conditions the strengths achieved were negligible and insufficient for structural application. The potential for geopolymers as a method of stabilising unfired earth bricks is discussed with respect to the compressive strengths achieved.

Study of Manufacture Process and Properties of Tailings and Slag Based Geopolymers

2010 ◽  
Vol 156-157 ◽  
pp. 803-807
Author(s):  
Fu Sheng Niu ◽  
Shan Shan Zhou ◽  
Shu Xian Liu ◽  
Jin Xia Zhang
Keyword(s):  
Compressive Strength ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Raw Material ◽  
Silicate Concentration ◽  
High Compressive Strength ◽  
Curing Period ◽  
Manufacture Process ◽  
Alkali Activated

The tailings and slag based geopolymers was prepared by sodium silicate, sodium hydroxide alkali-activated tailings and slag. The compressive strength in 7 d under different raw material proportion were tested. The result indicated that tailings and slag based geopolymers has high compressive strength . As the tailings in slag is 80%, the compressive strength in 7d can reach 45.10 MPa . As the Na2SiO3 to NaOH ratio is 0.5, the compressive strength in 7d can reach 63.79 MPa. As the NaOH and sodium silicate concentration in the solution is 35%, the compressive strength in 7d can reach 38.35 MPa respectively; As the curing period is 14 d , the compressive strength can reach 71.25 MPa. As the steel scoria in solid is 20%, the compressive strength in 7d can reach 61.86 MPa respectively.

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.

scholarly journals Artificial Intelligence Approaches for Prediction of Compressive Strength of Geopolymer Concrete

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 983 ◽  
Author(s):  
Dong Dao ◽  
Hai-Bang Ly ◽  
Son Trinh ◽  
Tien-Thinh Le ◽  
Binh Pham
Keyword(s):  
Artificial Intelligence ◽  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Steel Slag ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Partial Replacement ◽  
Geopolymer Concrete

Geopolymer concrete (GPC) has been used as a partial replacement of Portland cement concrete (PCC) in various construction applications. In this paper, two artificial intelligence approaches, namely adaptive neuro fuzzy inference (ANFIS) and artificial neural network (ANN), were used to predict the compressive strength of GPC, where coarse and fine waste steel slag were used as aggregates. The prepared mixtures contained fly ash, sodium hydroxide in solid state, sodium silicate solution, coarse and fine steel slag aggregates as well as water, in which four variables (fly ash, sodium hydroxide, sodium silicate solution, and water) were used as input parameters for modeling. A total number of 210 samples were prepared with target-specified compressive strength at standard age of 28 days of 25, 35, and 45 MPa. Such values were obtained and used as targets for the two AI prediction tools. Evaluation of the model’s performance was achieved via criteria such as mean absolute error (MAE), root mean square error (RMSE), and coefficient of determination (R2). The results showed that both ANN and ANFIS models have strong potential for predicting the compressive strength of GPC but ANFIS (MAE = 1.655 MPa, RMSE = 2.265 MPa, and R2 = 0.879) is better than ANN (MAE = 1.989 MPa, RMSE = 2.423 MPa, and R2 = 0.851). Sensitivity analysis was then carried out, and it was found that reducing one input parameter could only make a small change to the prediction performance.

scholarly journals Investigation on Mechanical and Durability Properties of Rapid Strength Gaining Concrete

2018 ◽  
Vol 7 (2.12) ◽  
pp. 406
Author(s):  
L Krishnaraj ◽  
P T. Ravichandran ◽  
Shaik AarifIlahi ◽  
V Ramanathan
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Cement Paste ◽  
Mechanical Tests ◽  
High Rate ◽  
Concrete Technology ◽  
Strength Concrete ◽  
Durability Properties ◽  
Content Ratio ◽  
Strength Tests

The strength of cement paste and aggregate components helps to decide the strength of the concrete, their properties of deformation, and the binding properties among the aggregate surface and cement paste. It is conceivable with many of the aggregates to form high strength concrete by increasing the cement paste strength, which can be controlled by choosing of water-content ratio and type of admixture dosage. The current scenario in the concrete technology and the accessibility of many kind of mineral and chemical admixtures, and special super plasticizer to gain the targeted compressive strength of a concrete. In this study MYK Remicrete PC30 and BASF Master Glennium ACE 30 were utilized as the admixtures as Add 1 and Add 2 which acts as high rate water reducing agents. These developments have led to increase uses of Rapid strength concrete. To compare the mechanical and durability properties of concrete using Fly ash and Admixtures the following tests were conducted on concrete tests specimens. Mechanical tests are to be conducted such as compressive strength tests, and tensile strength tests, durability tests like water absorption test, acid test by HCL, H2SO4 and HNO3. The result indicates that rate of development of compressive strength and tensile strength are higher for the concrete design mix which has HRWR admixture of 1% and FA of 20%.  

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