Influence of sodium hydroxide (NaOH) molarity on fresh properties of self-compacting slag-based geopolymer concrete containing recycled aggregate

2021 ◽  
Author(s):  
Khaleel H. Younis
Keyword(s):  
Sodium Hydroxide ◽  
Recycled Aggregate ◽  
Geopolymer Concrete ◽  
Fresh Properties

Rheological Behavior of Self-Compacting Geopolymer Concrete Containing Recycled Aggregates: Effect of Na2SiO3/NaOH and Molarity of NAOH

2021 ◽  
Vol 872 ◽  
pp. 79-84
Author(s):  
Koran Salihi ◽  
Khaleel H. Younis
Keyword(s):  
Sodium Hydroxide ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Geopolymer Concrete ◽  
Fresh Properties ◽  
Self Compacting Concrete ◽  
Sustainable Concrete ◽  
Coarse Aggregates ◽  
Concrete Mixtures ◽  
Fresh State

To develop a sustainable concrete and to minimize the depletion of the natural resources, an attempt was made to develop sustainable concrete mixtures benefiting from the geopolymer technology and the use of recycled aggregate in self-compacting geopolymer concrete (SCGC). This study aim to examine the effects of sodium hydroxide (SH) molarity and sodium silicate (Na2SiO3)/ sodium hydroxide (SS/SH) ration the fresh properties of SCGC mixtures containing recycled coarse aggregates (RCA) Mixes were prepared with three different molarity (8M, 10M and 12M) of) and four SS/SH ratios (1.5, 2.0, 2.5 and 3.0). Six mixes were examined in this study. The results were compared with the EFNARC limits for self-compacting concrete (SCC). It was found that the SS/SH ratio and the molarity of SH affect the fresh properties of (SCGC). However, the results showed that, SCGC mixtures containing RCA can be developed and satisfy the requirements of EFNARC for fresh state of SCC.

scholarly journals Mechanical Properties of Geopolymer Concrete Made With Partial Replacement of Coarse Aggregate by Recycled Aggregate

2019 ◽  
Vol 9 (1) ◽  
pp. 2301-2304 ◽  
Keyword(s):  
Mechanical Properties ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Coarse Aggregate ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Partial Replacement ◽  
Geopolymer Concrete ◽  
Recycled Coarse Aggregate ◽  
Coarse Aggregates

Construction is the one the fast growing field in the worldwide. There are many environmental issues connected with the manufacture of OPC, at the same time availability of natural coarse aggregate is getting reduced. Geopolymer binder and recycled aggregates are promising alternatives for OPC and natural coarse aggregates. It is produced by the chemical action of inorganic molecules and made up of Fly Ash, GGBS, fine aggregate, coarse aggregate and an alkaline solution of sodium hydroxide and sodium silicate. 10 M sodium hydroxide and sodium silicate alkali activators are used to synthesis the geopolymer in this study. Recycled aggregates are obtained from the construction demolished waste. The main focus of this work is to find out the mechanical properties of geopolymer concrete of grade G40 when natural coarse aggregate(NCA) is replaced by recycled coarse aggregate in various proportions such as 0%, 10%, 20%, 30%,40% and 50% and also to compare the results of geopolymer concrete made with recycled coarse aggregates(RAGPC) with geopolymer concrete of natural coarse aggregate(GPC) and controlled concrete manufactured with recycled aggregates(RAC) and controlled concrete of natural coarse aggregates(CC) of respective grade. It has been observed that the mechanical properties are enhanced in geopolymer concrete, both in natural coarse aggregate and recycled coarse aggregate up to 30% replacement when it is compared with the same grade of controlled concrete.

scholarly journals Strength Attainment of Geopolymer Concrete with GGBS at Ambient Curing

2019 ◽  
Vol 9 (2S2) ◽  
pp. 56-59
Keyword(s):  
Tensile Strength ◽  
Ambient Temperature ◽  
Sodium Hydroxide ◽  
Cross Sections ◽  
Strength Properties ◽  
Industrial Wastes ◽  
Mix Design ◽  
Geopolymer Concrete ◽  
Ambient Curing ◽  
Test Result

Geopolymer concrete plays a major role in concrete industry by replacing cement and using the industrial wastes. In this study, the cement is completely replaced by GGBS and strength properties are analyzed. An M30 mix design is prepared and the specimens are cast and tested. For this, sodium hydroxide and sodium silicate are used as activator and its ratio is fixed as 1:2.5. Sodium hydroxide of 12 molarity, 550kg/m3 of GGBS is used in the study. Admixture La Hypercrete S25 (HTS code 38244090) is added in the mix by 1% of weight of GGBS to obtain the required workability. For compression study, cubes in 100 mm size are cast. Cylinders with 100mm dia and 200mm height are tested for splitting tensile strength and beam specimens of 500mm long and 100mm cross sections were cast for determining the flexure behaviour. The beams are subjected to ambient curing and tested at 3, 7, 14, 28 and 56 days. The test result shows that there is a gradual increment in all the strengths from 3 to 56 days and it proves that geopolymer concrete with GGBS cured at ambient temperature performs well in the strength properties.

scholarly journals Resistance of Acid Attack on Geopolymer Concrete Developed with Partial Replacement of Course Aggregate by Recycled Aggregate

2019 ◽  
Vol 8 (4) ◽  
pp. 12142-12146
Keyword(s):  
Fly Ash ◽  
Coarse Aggregate ◽  
Recycled Aggregate ◽  
Partial Replacement ◽  
Geopolymer Concrete ◽  
Acid Attack ◽  
Great Strength ◽  
Conventional Concrete ◽  
Existing Structures ◽  
Binder Material

Geopolymer concrete is one of the major developments in recent years resulting in utilization of fly ash in huge quantities and eventually reducing cement consumption and ultimately reducing emission of greenhouse gases.The geopolymer concrete is produced by using activated fly ash as binder material instead of cement. Geopolymer concrete accomplishes great strength and looks similar to conventional concrete. Recycled coarse aggregate (RCA )which is coming from demolition of construction of old and existing structures has been used in this study. The durability property; acid attack resistance with partial replacement of coarse aggregate by recycled aggregate in geopolymer and conventional concrete for the different composition such as 10, 20, 30 and 40percentage for a period of 15, 45,75 and 105 days has been evaluated. From the results it was observed that in both natural and recycled aggregate of Geopolymer concrete is highly resistant to acids such as sulphuric acid and hydrochloric acid compared to conventional concrete of respective aggregates.

scholarly journals A Machine Learning-Assisted Numerical Predictor for Compressive Strength of Geopolymer Concrete Based on Experimental Data and Sensitivity Analysis

2020 ◽  
Vol 10 (21) ◽  
pp. 7726
Author(s):  
An Thao Huynh ◽  
Quang Dang Nguyen ◽  
Qui Lieu Xuan ◽  
Bryan Magee ◽  
TaeChoong Chung ◽  
...  
Keyword(s):  
Neural Network ◽  
Machine Learning ◽  
Sensitivity Analysis ◽  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Engineering Properties ◽  
Percentage Error ◽  
Geopolymer Concrete ◽  
Statistical Measures

Geopolymer concrete offers a favourable alternative to conventional Portland concrete due to its reduced embodied carbon dioxide (CO2) content. Engineering properties of geopolymer concrete, such as compressive strength, are commonly characterised based on experimental practices requiring large volumes of raw materials, time for sample preparation, and costly equipment. To help address this inefficiency, this study proposes machine learning-assisted numerical methods to predict compressive strength of fly ash-based geopolymer (FAGP) concrete. Methods assessed included artificial neural network (ANN), deep neural network (DNN), and deep residual network (ResNet), based on experimentally collected data. Performance of the proposed approaches were evaluated using various statistical measures including R-squared (R2), root mean square error (RMSE), and mean absolute percentage error (MAPE). Sensitivity analysis was carried out to identify effects of the following six input variables on the compressive strength of FAGP concrete: sodium hydroxide/sodium silicate ratio, fly ash/aggregate ratio, alkali activator/fly ash ratio, concentration of sodium hydroxide, curing time, and temperature. Fly ash/aggregate ratio was found to significantly affect compressive strength of FAGP concrete. Results obtained indicate that the proposed approaches offer reliable methods for FAGP design and optimisation. Of note was ResNet, which demonstrated the highest R2 and lowest RMSE and MAPE values.

scholarly journals Developing Geopolymer Concrete Properties by Using Nanomaterials and Steel Fibers

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
E. Rabiaa ◽  
R. A. S. Mohamed ◽  
W. H. Sofi ◽  
Taher A. Tawfik
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Sodium Hydroxide ◽  
Steel Fiber ◽  
Splitting Tensile Strength ◽  
Steel Fibers ◽  
Hardened Concrete ◽  
Geopolymer Concrete ◽  
Alkaline Activator ◽  
The Impact

This research investigates the simultaneous impact of two different types of steel fibers, nanometakaolin, and nanosilica on the mechanical properties of geopolymer concrete (GPC) mixes. To achieve this aim, different geopolymer concrete mixes were prepared. Firstly, with and without nanomaterials (nanosilica and nanometakaolin) of 0, 2%, 4%, 6%, and 8% from ground granulated blast furnace slag (GGBFS) were used. Secondly, steel fiber (hooked end and crimped) content of (0, 0.5%, 1, and 1.5%) was used. Thirdly, optimum values of nanomaterials with the optimum values of steel fiber were used. Crimped and hooked-end steel fibers were utilized with an aspect ratio of 60 and a length of 30 mm. Geopolymer mixes were manufactured by using a constant percentage of alkaline activator to binder proportion equal to 0.45 with GGBFS cured at ambient conditions. For alkaline activator, sodium hydroxide molar (NaOH) and sodium hydroxide solution (NaOH) were used according to a proportion (Na2SiO3/NaOH) of 2.33. The hardened concrete tests were performed through the usage of splitting tensile strength, flexural, and compressive experiments to determine the impact of steel fibers, nanometakaolin, and nanosilica individually and combined on performance of GPC specimens. The results illustrated that using a mix composed of the optimum steel fibers (1% content) accompanied by an optimum percentage of 6% nanometakaolin or 4% nanosilica demonstrated a significant enhancement in the mechanical properties of GPC specimens compared to all other mixtures. Besides, the impact of using nanomaterials individually was found to be predominant on compressive strength on GPC specimens especially with the usage of the optimum values. However, using nanomaterials individually compared to using the steel fibers individually was found to have approximately the same splitting tensile strength and flexural performance.

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.

The Effect of NaOH Concentration and Curing Condition to the Strength and Shrinkage Performance of Recycled Geopolymer Concrete

2014 ◽  
Vol 803 ◽  
pp. 194-200 ◽  
Author(s):  
Ahmad Ruslan Mohd Ridzuan ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Mohd Fadzil Arshad ◽  
Muhammad Faheem Mohd Tahir ◽  
A.A. Khairulniza
Keyword(s):  
Portland Cement ◽  
Sodium Hydroxide ◽  
Waste Paper ◽  
Paper Sludge ◽  
Concrete Aggregate ◽  
Geopolymer Concrete ◽  
Recycle Concrete Aggregate ◽  
Paper Sludge Ash ◽  
Curing Condition ◽  
Sludge Ash

Concrete is widely used as a material construction. Globally, the consumption of concrete was estimated to be more than 8 billion tons per year. Nowadays, many problems arise related to concrete manufacturing occur especially on environmental issues. A key concern for environmentalists has always been climate change. One of the ways to mitigate the impact activities on the climate is to reduce carbon footprint. Portland cement are commonly been used in concrete is responsible for about 5% of all CO2emission. It is reported by Davidovit that the production of one ton of Portland cement emits approximately one ton of CO2into the atmosphere. There are several ways to reduce environmental pollution that cause by production and utilization of Portland cement, one of it is Geopolymer concrete. Subsequently Geopolymer concrete incorporating with recycle concrete aggregate (RCA) is one of the alternative to further reduce carbon footprint and as well as can reduce waste. Geopolymer concrete is a concrete that use no cement and produced by the combination of alkaline activator and supplementary cementitious material (SCM) such as fly ash, boiler ash, waste paper sludge ash (WPSA), ground granulated blast-furnace slag (GGBS), and so on in order to reduce carbon emission. In this study the Waste Paper Sludge Ash (WPSA) were used as a SCM and the combination of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) as a binder. Two (2) series of geopolymer concrete specimens comprising two (2) different molar of sodium hydroxide (NaOH) which are 8M and 14M were adopted. The effect variable alkaline molarity on the compressive strength and shrinkage of the geopolymer concrete specimens is tested at the age of 3, 7, 14 and 28 days. The mixture of geopolymer concete with 8M of sodium hydroxide (NaOH) concentration then was categorized into three (3) groups. Each group were been cured at different curing condition which are in ambient condition, oven, and external condition. The size of specimens prepared were 100mm x 100mm x100mm. The result shows that the molarities of sodium hydroxide (NaOH) influenced the strength of Waste Paper Sludge Ash (WPSA) based geopolymer concrete produced incorporating with increasing of recycle concrete aggregate (RCA). The result also show that the geopolymer concrete undergoes very low shrinkage. Curing condition will also effect the strength of geopolymer concrete produced.

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