Chloride-induced corrosion of reinforcement in low-calcium fly ash-based geopolymer concrete

2016 ◽  
Vol 88 ◽  
pp. 96-107 ◽  
Author(s):  
M. Babaee ◽  
A. Castel
Keyword(s):  
Fly Ash ◽  
Geopolymer Concrete ◽  
Chloride Induced Corrosion ◽  
Low Calcium

scholarly journals Practical Prediction Models of Tensile Strength and Reinforcement-Concrete Bond Strength of Low-Calcium Fly Ash Geopolymer Concrete

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 875
Author(s):  
Chenchen Luan ◽  
Qingyuan Wang ◽  
Fuhua Yang ◽  
Kuanyu Zhang ◽  
Nodir Utashev ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Fly Ash ◽  
Bond Strength ◽  
Prediction Models ◽  
Splitting Tensile Strength ◽  
Geopolymer Concrete ◽  
Structural Factors ◽  
Test Results ◽  
Portland Cement Concrete ◽  
Low Calcium

There have been a few attempts to develop prediction models of splitting tensile strength and reinforcement-concrete bond strength of FAGC (low-calcium fly ash geopolymer concrete), however, no model can be used as a design equation. Therefore, this paper aimed to provide practical prediction models. Using 115 test results for splitting tensile strength and 147 test results for bond strength from experiments and previous literature, considering the effect of size and shape on strength and structural factors on bond strength, this paper developed and verified updated prediction models and the 90% prediction intervals by regression analysis. The models can be used as design equations and applied for estimating the cracking behaviors and calculating the design anchorage length of reinforced FAGC beams. The strength models of PCC (Portland cement concrete) overestimate the splitting tensile strength and reinforcement-concrete bond strength of FAGC, so PCC’s models are not recommended as the design equations.

scholarly journals Alkali-Silica Reaction Resistance and Pore Solution Composition of Low-Calcium Fly Ash-Based Geopolymer Concrete

2020 ◽  
Vol 5 (11) ◽  
pp. 96
Author(s):  
Jiawei Lei ◽  
Jiajun Fu ◽  
En-Hua Yang
Keyword(s):  
Fly Ash ◽  
Pore Solution ◽  
Systematic Investigation ◽  
Alkali Silica Reaction ◽  
Geopolymer Concrete ◽  
Portland Cement Concrete ◽  
Solution Composition ◽  
Low Calcium ◽  
Underlying Mechanisms ◽  
One Year

Low-calcium fly ash-based geopolymer concrete is generally reported to be less vulnerable to alkali-silica reaction (ASR) than conventional ordinary Portland cement concrete. However, the lack of understanding of pore solution composition of the low-calcium fly ash-based geopolymer limits the investigation of the underlying mechanisms for the low ASR-induced expansion in the geopolymer concrete. This study presents a systematic investigation of the pore solution composition of a low-calcium fly ash-based geopolymer over a period of one year. The results show that the pore solution of the fly ash geopolymer is mainly composed of alkali ions, silicates, and aluminosilicates species. The lower expansion of the geopolymer concrete in the current study is most probably due to the insufficient alkalinity in the geopolymer pore solution as the hydroxide ions are largely consumed for the fly ash dissolution.

scholarly journals Studies on effect of sugarcane bagasse fibre on mechanical properties and workability of low calcium fly ash and slag based geopolymer concrete

2021 ◽  
Vol 309 ◽  
pp. 01112
Author(s):  
T. Srinivas ◽  
Srimanthula Chandana ◽  
N V Ramana Rao
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Sugarcane Bagasse ◽  
Rest Period ◽  
Geopolymer Concrete ◽  
Inorganic Polymers ◽  
Low Calcium ◽  
Hardened Properties ◽  
Bagasse Fibre

Individuals from the group of inorganic polymers are known as geopolymers. The geopolymer material's compound organisation is similar to that of typical zeolitic materials, however the microstructure is undefined rather than translucent. The polymerisation interaction includes a considerably quick substance response under antacid condition on Si-Al minerals and that meets the basic properties of concrete as well as falls under classification of manageability. Utilization of various fibres like steel, glass, sugarcane bagasse etc, significantly influences fresh and hardened properties of concrete. Sugarcane bagasse fibre is a by-product from sugar industries and can be used as a fibre in concrete. The target of this paper is to study an effect of sugarcane bagasse fibre on mechanical properties such as compressive, tensile and flexural sgength and also the workability of low calcium fly ash (Class-F) and slag based geopolymer concrete of G40 grade which is équivalent to M40.. Sugarcane baggase ash fibre has been used for both the concencrte G40 and M40 as 0.5%,1%,1.5%,2%. All the samples were casted and oven cured at 60o for 24 hours after one day rest period and remaining days cured in an ambient temperature, then tested on 3rd, 7th and 28th day to assess the mechanical properties, such as Compressive, Tensile, and Flexure strength. The results were compared among controlled concrete (CC), controlled concrete with sugarcane bagasse fibre (CCF), geopolymer concrete (GPC) and geopolymer concrete with sugarcane bagasse fibre (GPCF). The results revealed that with addition of SCBF, the mechanical properties have been enhanced significantly.

Engineering and Microstructures Characteristics of Low Calcium Fly Ash Based Geopolymer Concrete

2017 ◽  
Author(s):  
Akram S. Mahmoud ◽  
Ganjeena J. Khoshnaw ◽  
Faten I.Mahmood
Keyword(s):  
Fly Ash ◽  
Geopolymer Concrete ◽  
Low Calcium

SERVICEABILITY OF LOW CREEP FLY ASH GEOPOLYMER CONCRETE BEAMS

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Arnaud Castel ◽  
Stephen Foster ◽  
Raymond Ian Gilbert
Keyword(s):  
Fly Ash ◽  
Concrete Beams ◽  
Drying Shrinkage ◽  
Performance Criterion ◽  
Geopolymer Concrete ◽  
Curing Conditions ◽  
Model Code ◽  
Sustained Loading ◽  
Low Calcium ◽  
Eurocode 2

In reinforced concrete construction, deflection control is an important performance criterion for their serviceability. The aim of the research described in this paper is to assess the deformation of cracked reinforced geopolymer concrete beams under long term service loading. The geopolymer binder is Portland cement free, using 85% of low calcium fly ash, 15% of GGBFS (Ground Granulated Blast Furnace Slag) and a sodium silicate/sodium hydroxide based activator. Firstly, geopolymer concrete drying shrinkage and creep were measured. Different curing conditions at elevated temperature were used. All experimental results are compared to predictions made using the Eurocode 2. Secondly, geopolymer concrete beams were subjected to short time bending tests leading to concrete cracking (pre-cracking tests). Beams were then stored under sustained loading for a period of four months. Both deflection and cracks were monitored versus time. Results show that, providing an appropriate heat curing regime, geopolymer concrete creep is much lower than that observed for OPC concrete and predicted by the Eurocode 2. As a result, the time-dependent deflection of geopolymer concrete beams measured after 4 months under sustained loading was always significantly lower than that of traditional OPC concrete beams. All results are showing that the crack widths of geopolymer concrete beams are significantly smaller than those expected for OPC concrete beams according to fib model code 2010 for both short and long terms tests. It is concluded that low calcium fly ash-based geopolymer concrete is a promising option for precast applications.

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