scholarly journals Proposing Several Model Techniques Including ANN and M5P-tree to Forecast the Stress at the Failure of Geopolymer Concrete Mixtures Incorporated Nano-silica

2022 ◽  
Author(s):  
Hemn Unis Ahmed ◽  
Ahmed S. Mohammed ◽  
Azad A. Mohammed
Keyword(s):  
Portland Cement ◽  
Alkaline Solution ◽  
Cementitious Materials ◽  
The Other ◽  
Curing Temperature ◽  
Model Parameters ◽  
Geopolymer Concrete ◽  
Ann Model ◽  
Nano Silica ◽  
Binder Ratio

Abstract Geopolymers are innovative cementitious materials that can completely replace traditional Portland cement composites and have a lower carbon footprint than Portland cement. Recent efforts have been made to incorporate various nanomaterials, most notably nano-silica (nS), into geopolymer concrete (GPC) to improve the composite's properties and performance. Compression strength (CS) is one of the essential properties of all types of concrete composites, including geopolymer concrete. As a result, creating a credible model for forecasting concrete CS is critical for saving time, energy, and money, as well as providing guidance for scheduling the construction process and removing formworks. This paper presents a large amount of mixed design data correlated to mechanical strength using empirical correlations and neural networks. Several models, including artificial neural network, M5P-tree, linear regression, nonlinear regression, and multilogistic regression models were utilized to create models for forecasting the CS of GPC incorporated nS. In this case, about 207 tested CS values were collected from literature studies and then analyzed to promote the models. For the first time, eleven effective variables were employed as input model parameters during the modeling process, including the alkaline solution to binder ratio, binder content, fine and coarse aggregate content, NaOH and Na2SiO3 content, Na2SiO3/NaOH ratio, molarity, nS content, curing temperatures, and ages. The developed models were assessed using different statistical tools such as RMSE, MAE, SI, OBJ value, and R2. Results revealed that the ANN model estimated the CS of GPC incorporated nS more accurately than the other models. On the other hand, the alkaline solution to binder ratio, molarity, NaOH content, curing temperature, and ages were those parameters that have significant influences on the CS of GPC incorporated nS.

scholarly journals STRENGTH AND DURABILITY PERFORMANCE OF FLY ASH BASED GEOPOLYMER CONCRETE USING NANO SILICA

2020 ◽  
Vol 4 (2) ◽  
pp. 1-12
Author(s):  
SAMEER VYAS ◽  
Sameer Mohammad ◽  
Shilpa Pal ◽  
Neetu Singh
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Geopolymer Concrete ◽  
Infrastructure Development ◽  
X Ray Diffraction ◽  
Nano Silica ◽  
Adverse Conditions ◽  
Concrete Production ◽  
Class F Fly Ash ◽  
Strength And Durability

With the increasing infrastructure development across the globe, the demand of cement  production increases day by day. However, the production of cement is associated with the emission of large amount of CO2 causing global warming. Scientist and engineers are in search of a green eco friendly alternative  for concrete production. Geopolymers are rapidly emerging as an alternative to Portland cement as the binder of structural concrete. In this respect, the fly ash based geopolymers  shows considerable prospect for application in concrete industry as an alternative binder to the Portland cement. Development of geopolymer concrete using class F fly ash brings many advantages like; enhancing workability, durability, better strength as well as lowering the price. There is not only a reduction in the greenhouse footprint but, also considerable increase in strength and resistivity to adverse conditions. In order to enhance the performance of Geopolymer concrete, the use of  Nano-silica is  found to be suitable and practiced by researchers.  Use of Nano materials as fillers in the concrete matrix has proven effective in increasing mechanical and durability properties. This research is based on performance evaluation of geopolymer concrete using different percentage of Nano-silica.. It was observed that Geopolymer concrete  with Nano-silica ( GPC-N)  shows good compressive strength as well as  durability under aggressive conditions. The materials performance were also investigated using X-Ray Diffraction technique. (XRD). Results show that the presence of nano silica  enhanced the performance of Geopolymer concrete with respect to strength and durability purposes.  

scholarly journals Sustainable cementitious materials: The effect of fly ash percentage as a part replacement of portland cement composite (PCC) and curing temperature on the early age strength of fly ash concrete

2019 ◽  
Vol 258 ◽  
pp. 01001
Author(s):  
Gidion Turuallo ◽  
Harun Mallisa
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Cement Composite ◽  
Cementitious Materials ◽  
Curing Temperature ◽  
Early Age ◽  
Water Tank ◽  
Lower Strength ◽  
Fly Ash Concrete ◽  
Lower Temperature

This research aims to determine the effect of fly ash percentage as a part replacement of Portland cement and curing temperatures to the early age strength of concrete. The percentages of fly ash used were 0, 10 and 15% by cement weight. The cured temperatures were 25, 30 dan 50°C. The concrete specimens were cubes of 150 x 150 x 150 mm3. The cubes, which were cured at 25°C, placed in water tank, while those cured at 30 and 50°C cured in oven until 7 days and then continued in water. The testing was conducted at ages 3, 7, 14 dan 28 days. The results showed that at early ages, the strength of concrete without fly ash cured at 25°C were higher than that of fly ash concrete. The higher level replacement of cement with fly ash, the lower strength of concrete obtained. The higher the curing temperature at earlier age resulted the higher the strength of concrete. The strength of concretes with 10% of fly ash cured at 25, 30 and 50°C at age three days were 15.111, 15.481 and 16.296 MPa respectively. Conversely, the strength of concrete that of cured at higher temperatures at ages 28 days, were lower than that of concretes cured at lower temperature. The results of this research also showed that fly ash could improve the workability of concrete.

Stabilization of Sulfate-Containing Soil by Cementitious Mixtures Mechanical Properties

2003 ◽  
Vol 1837 (1) ◽  
pp. 12-19 ◽  
Author(s):  
Lan Wang ◽  
Amitava Roy ◽  
Roger K. Seals ◽  
John B. Metcalf
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Cementitious Materials ◽  
Curing Temperature ◽  
Type I ◽  
Size Fractions ◽  
Granulated Blast Furnace Slag ◽  
Local Parish ◽  
Stabilized Soil ◽  
North Louisiana

Winn Rock (CaSO4) gravel from a quarry in Winn Parish in north Louisiana was used extensively as a surface course for local parish roads. Stabilization of these roads with Type I portland cement followed by an overlay of asphaltic concrete resulted in heaving. A study was undertaken to investigate the cause or causes of the expansion as well as to identify an alternate means of stabilization. Specimens of representative soil from the affected area were stabilized in the laboratory using various cementitious materials and were cured using a variety of methods. The mix contained 5% to 20% cementitious material. The cementitious materials were Type I portland cement, lime, and supplementary cementing materials such as granulated blast furnace slag (BFS), Class C fly ash (CFA), silica fume, and an amorphous silica (AS). The unconfined compressive strength of the stabilized soil was determined. The effect of size fractions other than the gravel on the expansion was assessed, and the expansion of the specimens over time was monitored. The cement and BFS mixtures almost doubled the compressive strength of the specimens compared with portland cement alone. The finer size fractions were responsible for expansion. The magnitude of expansion was directly proportional to the amount of Type I portland cement, the amount of available moisture, and the curing temperature. Replacement of a part of the portland cement by BFS significantly reduced the amount of expansion even at the highest moisture content. No expansion was detected when CFA and AS partially replaced the cement.

Crack Growth Resistance in Fibre Reinforced Geopolymer Concrete Exposed to Sustained Extreme Temperatures

2016 ◽  
Vol 711 ◽  
pp. 511-518 ◽  
Author(s):  
Vivek Bindiganavile ◽  
Jose R.A. Goncalves ◽  
Yaman Boluk
Keyword(s):  
Portland Cement ◽  
Crack Growth ◽  
Volume Fraction ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Geopolymer Concrete ◽  
Extreme Temperatures ◽  
Portland Cement Concrete ◽  
Promising Alternative ◽  
Cement Binder

Portland cement concrete (PCC) is now second only to potable water in per capita consumption. And notwithstanding its numerous benefits, Portland cement itself is responsible for between 4 to 5% of the world’s manmade greenhouse gas emissions. In this context, geopolymer concrete is a promising alternative, wherein the Portland cement binder is replaced entirely by supplementary cementitious materials triggered by alkaline activators. Relatively little is known on the fracture response of this system, especially when exposed to extreme temperatures. The study reported here focused on the crack growth response of such a system prepared with Class F fly ash and reinforced with steel and polymeric fibres up to 1% volume fraction. The geopolymerization was effected with a blend of sodium hydroxide and sodium silicate to achieve a compressive strength of 30 MPa at 28 days. The resulting geopolymer concrete was subjected to temperatures between-30 oC to 300 oC, sustained for 2 hours. A fibre blend of steel to polypropylene in the mass ratio of 4:1 was incorporated. Based on the results, four different stages for fracture behaviour were identified with superior fibre efficiency seen at sub-zero temperatures.

scholarly journals Peculiarities of hydration of Portland cement with synthetic nano-silica

2017 ◽  
Vol 12 (2) ◽  
pp. 101-106 ◽  
Author(s):  
Galyna Kotsay
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Portland Cement ◽  
Cement Hydration ◽  
Physical And Mechanical Properties ◽  
The Other ◽  
Nano Materials ◽  
Nano Silica ◽  
Other Hand ◽  
Materials Used

Abstract Application of nano-materials in cement products significantly, improves their properties. Of course, the effectiveness of the materials depends on their quantity and the way they are introduced into the system. So far, amongst nano-materials used in construction, the most preferred was nano-silica. This research investigated the effect of synthetic precipitated nano-silica on the cement hydration as well as, on the physical and mechanical properties of pastes and mortars. Obtained results showed that admixture of nano-silica enhanced flexural and compressive strength of cement after 2 and 28 days, however, only when admixture made up 0.5% and 1.0%. On the other hand, the use of nano-silica in the amount 2% had some limitations, due to its ability to agglomerate, which resulted in deterioration of the rheological and mechanical properties.

scholarly journals Study on Preparation of Coal Gangue-Based Geopolymer Concrete and Mechanical Properties

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Daming Zhang ◽  
Fangjin Sun ◽  
Tiantian Liu
Keyword(s):  
Mechanical Properties ◽  
Raw Materials ◽  
Mechanical Tests ◽  
Coal Gangue ◽  
Curing Temperature ◽  
Geopolymer Concrete ◽  
Dry Powder ◽  
Binder Ratio ◽  
Temperature Water ◽  
Water Binder Ratio

Alkaline dry powder activator, coal gangue, fly ash, and other raw materials are utilized to prepare coal gangue-based geopolymer concrete. The procedures of making the coal gangue-based geopolymer concrete are illustrated firstly. Also, basic mechanical properties, such as compressive strength and flexural strength of the geopolymer concrete, are studied through mechanical tests. The basic mechanical properties of ordinary concrete and coal gangue-based geopolymer concrete with different activation methods were compared and analyzed. Effects of curing temperature, curing time, water-binder ratio, and sand ratio on the basic mechanical properties of coal gangue-based geopolymer concrete activated by alkaline dry powder were studied. The optimal curing temperature, water-binder ratio, and sand ratio range of coal gangue-based geopolymer concrete activated by alkaline dry powder are obtained, respectively.

scholarly journals Textile Reinforced Concrete in Combination with Improved Self-Healing Ability Caused by Crystalline Admixture

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5787
Author(s):  
Hana Žáková ◽  
Jiří Pazderka ◽  
Pavel Reiterman
Keyword(s):  
Reinforced Concrete ◽  
Portland Cement ◽  
Concrete Structures ◽  
Cementitious Materials ◽  
Independent Study ◽  
The Other ◽  
Self Healing ◽  
Textile Reinforced Concrete ◽  
Secondary Hydration

The main aim of this study was to investigate the improved autogenous healing of concrete caused by a crystalline admixture in combination with textile reinforced concrete (TRC). This phenomenon (improved healing) has not yet been described by any independent study, and not at all in relation to TRC. The results of the study confirmed that the interaction between TRC and the crystalline admixture’s self-healing ability is advantageous and usable. The application of crystalline admixture could ensure the long-term entirety of the TCR element, where microcracks could occur. This allows for the creation of advantageous, thin (achieved by TRC) and waterproof (achieved by the crystalline admixtures) concrete structures. Moreover, this does not depend on temperature in the range of 4–30 °C (lower temperatures are of course problematic, as for most other cementitious materials). However, the interaction of both materials has its limits; the cracks must not be too wide (max. 0.1 mm), otherwise they will not heal. On the other hand, the advantage is that it does not matter what type of cement is used (CEM I and CEM II showed the same results), and the composition of the newly formed crystals in the cracks corresponds to the composition of the C-S-H gel, so it can be assumed that secondary hydration of the Portland cement occurred in the crack area.

Sign in / Sign up

Export Citation Format

Share Document