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.

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.

Microstructure Study on Optimization of High Strength Fly Ash Based Geopolymer

2012 ◽  
Vol 476-478 ◽  
pp. 2173-2180 ◽  
Author(s):  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamarudin Hussin ◽  
Mohammed Binhussain ◽  
Ismail Khairul Nizar ◽  
Rafiza Abd Razak ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
High Strength ◽  
Curing Temperature ◽  
Mix Design ◽  
Dense Matrix ◽  
Microstructural Characteristics ◽  
Naoh Solution ◽  
Alkaline Activator

The compressive strength and microstructural characteristics of fly ash based geopolymer with alkaline activator solution were investigated. The sodium hydroxide and sodium silicate were mixed together to form an alkaline activator. Three parameters including NaOH molarity, mix design (fly ash/alkaline activator ratio and Na2SiO3/NaOH ratio), and curing temperature were examined. The maximum strength of 71 MPa was obtained when the NaOH solution of 12M, fly ash/alkaline activator of 2.0, Na2SiO3/NaOH of 2.5 and curing temperature of 60°C were used at 7th days of testing. The results of SEM indicated that for geopolymer with highest strength, the structure was dense matrix and contains less unreacted fly ash with alkaline activator

Effects of Nano-CaCO3 on the Compressive Strength and Microstructure of High Strength Concrete in Different Curing Temperature

2011 ◽  
Vol 121-126 ◽  
pp. 126-131 ◽  
Author(s):  
Qing Lei Xu ◽  
Tao Meng ◽  
Miao Zhou Huang
Keyword(s):  
Compressive Strength ◽  
Low Temperature ◽  
High Strength Concrete ◽  
High Strength ◽  
Curing Temperature ◽  
Test Results ◽  
Strength Concrete ◽  
Calcium Nitrite ◽  
Orientation Index ◽  
Early Strength

In this paper, effects of nano-CaCO3 on compressive strength and Microstructure of high strength concrete in standard curing temperature(21±1°C) and low curing temperature(6.5±1°C) was studied. In order to improve the early strength of the concrete in low temperature, the early strength agent calcium nitrite was added into. Test results indicated that 0.5% dosage of nano-CaCO3 could inhibit the effect of calcium nitrite as early strength agent, but 1% and 2% dosage of nano-CaCO3 could improve the strength of the concrete by 13% and 18% in standard curing temperature and by 17% and 14% in low curing temperature at the age of 3days. According to the XRD spectrum, with the dosage up to 1% to 2%, nano-CaCO3 can change the orientation index significantly, leading to the improvement of strength of concrete both in standard curing temperature and low curing temperature.

scholarly journals Alkali Activated Paste and Concrete Based on of Biomass Bottom Ash with Phosphogypsum

2020 ◽  
Vol 10 (15) ◽  
pp. 5190
Author(s):  
Danutė Vaičiukynienė ◽  
Dalia Nizevičienė ◽  
Aras Kantautas ◽  
Vytautas Bocullo ◽  
Andrius Kielė
Keyword(s):  
Compressive Strength ◽  
Sodium Hydroxide ◽  
Sodium Hydroxide Solution ◽  
Bottom Ash ◽  
Control Sample ◽  
Test Methods ◽  
X Ray ◽  
Hydroxide Solution ◽  
Fine Grained ◽  
Alkali Activated

There is a growing interest in the development of new cementitious binders for building construction activities. In this study, biomass bottom ash (BBA) was used as aluminosilicate precursor and phosphogypsum (PG) was used as a calcium source. The mixtures of BBA and PG were activated with the sodium hydroxide solution or the mixture of sodium hydroxide solution and sodium silicate hydrate solution. Alkali activated binders were investigated using X-ray powder diffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy (SEM) test methods. The compressive strength of hardened paste and fine-grained concrete was also evaluated. After 28 days, the highest compressive strength reached 30.0 MPa—when the BBA was substituted with 15% PG and activated with NaOH solution—which is 14 MPa more than control sample. In addition, BBA fine-grained concrete samples based on BBA with 15% PG substitute activated with NaOH/Na2SiO3 solution showed higher compressive strength compered to when NaOH activator was used −15.4 MPa and 12.9 MPa respectfully. The NaOH/Na2SiO3 activator solution resulted reduced open porosity, so potentially the fine-grained concrete resistance to freeze and thaw increased.

scholarly journals Crossover Effect in Cement-Based Materials: A Review

2019 ◽  
Vol 9 (14) ◽  
pp. 2776 ◽  
Author(s):  
Sumra Yousuf ◽  
Payam Shafigh ◽  
Zainah Ibrahim ◽  
Huzaifa Hashim ◽  
Mohammad Panjehpour
Keyword(s):  
Compressive Strength ◽  
Construction Industry ◽  
Building Materials ◽  
Cement Hydration ◽  
Curing Temperature ◽  
Future Research ◽  
Hydration Products ◽  
Crossover Effect ◽  
Cement Based Materials ◽  
Mineral Compositions

Cement-based materials (CBMs) such as pastes, mortars and concretes are the most frequently used building materials in the present construction industry. Cement hydration, along with the resulting compressive strength in these materials, is dependent on curing temperature, methods and duration. A concrete subjected to an initial higher curing temperature undergoes accelerated hydration by resulting in non-uniform scattering of the hydration products and consequently creating a great porosity at later ages. This phenomenon is called crossover effect (COE). The COE may occur even at early ages between seven to 10 days for Portland cements with various mineral compositions. Compressive strength and other mechanical properties are important for the long life of concrete structures, so any reduction in these properties is of great concern to engineers. This study aims to review existing information on COE phenomenon in CBMs and provide recommendations for future research.

scholarly journals Effect of Curing Temperature Histories on the Compressive Strength Development of High-Strength Concrete

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Keun-Hyeok Yang ◽  
Jae-Sung Mun ◽  
Myung-Sug Cho
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Relative Strength ◽  
Curing Temperature ◽  
Strength Development ◽  
Curing Conditions ◽  
Strength Concrete ◽  
Equivalent Age ◽  
Compressive Strength Development

This study examined the relative strength-maturity relationship of high-strength concrete (HSC) specifically developed for nuclear facility structures while considering the economic efficiency and durability of the concrete. Two types of mixture proportions with water-to-binder ratios of 0.4 and 0.28 were tested under different temperature histories including (1) isothermal curing conditions of 5°C, 20°C, and 40°C and (2) terraced temperature histories of 20°C for an initial age of individual 1, 3, or 7 days and a constant temperature of 5°C for the subsequent ages. On the basis of the test results, the traditional maturity function of an equivalent age was modified to consider the offset maturity and the insignificance of subsequent curing temperature after an age of 3 days on later strength of concrete. To determine the key parameters in the maturity function, the setting behavior, apparent activation energy, and rate constant of the prepared mixtures were also measured. This study reveals that the compressive strength development of HSC cured at the reference temperature for an early age of 3 days is insignificantly affected by the subsequent curing temperature histories. The proposed maturity approach with the modified equivalent age accurately predicts the strength development of HSC.

The Coating Property Study of (Meth)Acrylate Copolymer with Gradient Wettability Surfaces

2015 ◽  
Vol 723 ◽  
pp. 964-967
Author(s):  
Yong Zhang ◽  
Jiang Cheng
Keyword(s):  
Free Radical ◽  
Sodium Hydroxide ◽  
Sodium Hydroxide Solution ◽  
Performance Testing ◽  
Curing Temperature ◽  
Curing Agent ◽  
Additional Method ◽  
Coating Property ◽  
Acrylate Copolymer ◽  
Polymerization Method

The coating property of (meth) acrylate copolymer with gradient wettability surfaces was studied. The random (meth) acrylate copolymers can be obtained according to the free radical polymerization method and their coating property was analyzed according to performance testing. The gradient wettability surface was prepared by using the sodium hydroxide solution. The effects of the kinds of crosslinking monomer, mass ration of HEMA, additional method of HEMA, amount of curing agent and curing temperature on the coating property of (meth) acrylate copolymer were discussed. It was found that the mass ration of HEMA was 15 % and the additional method of HEMA was added previously when the molar ration of MMA/BA was 6/4. The amount of curing agent was 1.86 g and the curing temperature was 160 °C when the P (MMA-BA-HEMA) solutions were 10 g.

Impact of Plasticizers on Technological Properties of Gypsum

2016 ◽  
Vol 865 ◽  
pp. 130-134 ◽  
Author(s):  
Dušan Dolák ◽  
Karel Dvořák
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Mechanical Strength ◽  
Research Work ◽  
High Strength ◽  
Building Industry ◽  
Technological Properties ◽  
Accurate Comparison

Sulphate binders based on gypsum are widely used in building industry. This research work was focused on testing the influence of Melflux plasticizers on the final properties of the gypsum mixture. The aim was to determine the correct concentration of the plasticizer considering workability and improvement of mechanical properties, especially the compressive strength. Different concentrations of plasticizers were tested in mixture of alfa and beta plaster. Each batch was created as paste of normal consistency to create accurate comparison. The results of experiment show significant improvements of mechanical strength of the hardened mixture while maintaining same consistency. This knowledge can be utilized in the design of high-strength sulphate binders.

scholarly journals The Use of Fly Ash as Additive Material to High Strength Concrete

2018 ◽  
Vol 20 (2) ◽  
pp. 65-70
Author(s):  
Endah Kanti Pangestuti ◽  
Sri Handayani ◽  
Mego Purnomo ◽  
Desi Christine Silitonga ◽  
M. Hilmy Fathoni
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Strength Concrete ◽  
Building Materials ◽  
High Strength ◽  
Coal Waste ◽  
Normal Concrete ◽  
Strength Concrete ◽  
Concrete Mixtures ◽  
Compressive Strength Of Concrete

Abstract. The use of coal waste (Fly Ash) is currently being developed in building materials technology, as a high-strength concrete mix material. This study aims to determine the strength of concrete by adding fly ash as a substitute for cement in high-strength concrete mixtures. This research was conducted with an experimental method to obtain results and data that would confirm the variables studied. The total number of specimens used in this study were 36 pieces with different sizes of cube tests which were 15 cm x 15 cm x 15 cm. A total of 36 concrete samples were used to test the compressive strength of concrete with a percentage of Fly Ash in  0% (normal concrete), 20%, 25% and 30% with a concrete treatment age of 7 days, 21 days and 28 days. A total of 12 more samples were used to test water absorption in concrete at 28 days of maintenance. Each percentage percentage of Fly Ash uses 3 concrete test samples. The increase in compressive strength occurs at 7, 21 and 28 days in concrete. However, the compressive strength of concrete produced by concrete using the percentage of Fly Ash is always lower than the value of normal concrete compressive strength. From testing the compressive strength of concrete at 28 days of treatment with content of 0%, 20%, 25% and 30% Fly Ash obtained results of 45.87 MPa, 42.67 MPa, 40.89 MPa, and 35.27 MPa respectively

scholarly journals Appropriate Green Materials for Affordable Building Construction in Nigeria

2019 ◽  
Vol 8 (4) ◽  
pp. 986-991
Keyword(s):  
Low Income ◽  
Structural Equation ◽  
Building Materials ◽  
Low Cost ◽  
Central Zone ◽  
Green Building ◽  
Building Construction ◽  
High Price ◽  
North Central ◽  
Green Materials

There are severe issues for the deficiency of affordable house for low-income earners in developing countries such as Nigeria. The high cost of conventional materials has been established to be one the major factors that heightened the cost of building in recent times. However the integration of green building materials that are relevant and sustainable for building construction in the present dispensation will provide excellent solutions to overcome high price of construction. The study was carried out on all the available green materials in north-central Nigeria. Surveyed instrument was prepared and distributed to building professional experts that are registered member of various professional bodies in the building sector. Four hundred questionnaires were distributed in the north-central zone. Three hundred five questionnaires that were filled correctly was used for the data analyses. Analysis of moments (AMOS) software through the structural equation model (SEM) was used to analysis and generated a model for the study. The result discloses that earth bricks, stone/rocks, timber, Bamboo, thatches, straw fibre, and rice husk are very relevant green materials that can be used to achieve affordable building construction. Therefore, the use and integration of green materials in building construction will produce low cost housing units

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