Drying Shrinkage of Fly Ash-Based Self-Compacting Geopolymer Concrete

2014 ◽  
Vol 567 ◽  
pp. 362-368 ◽  
Author(s):  
M.F. Nuruddin ◽  
F.A. Memon ◽  
N. Shafiq ◽  
S. Demie
Keyword(s):  
Fly Ash ◽  
Relative Humidity ◽  
Drying Shrinkage ◽  
Time Dependent ◽  
Geopolymer Concrete ◽  
Test Results ◽  
Shrinkage Behaviour ◽  
One Year ◽  
Curing Regime

–The drying shrinkage behaviour of fly-ash-based self-compacting geopolymer concrete (SCGC) was studied for a period of one year. Two SCGC and One OPC-based conventional mixture were used in the present investigation. Drying shrinkage test commenced on the 7th day after casting the test specimens. Once the appropriate curing regime was completed, the specimens from each mix were placed in the laboratory room where the temperature was maintained at 23°C, however, the relative humidity of the room varied between 56 and 64 percent. Strain readings taken at specific intervals were analyzed to determine the time-dependent deformations of each mixture. Test results indicated that the heat-cured fly ash-based SCGC experienced very low drying shrinkage than that of water-cured OPC based concrete. After one year of exposure, in comparison to 466 με, the value experienced by OPC concrete, the drying shrinkage strains of SCGC mix specimens ranged between 141 and 159 με. These values were about 65-70% lower than that of OPC concrete. It is anticipated that the findings of this investigation would help in predicting the behaviour of SCGC. Keywords-Fly ash, Geopolymer concrete, Self-compacting Geopolymer concrete, Drying shrinkage

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 Effect of Fly Ash on Compressive Strength, Drying Shrinkage, and Carbonation Depth of Mortar with Ferronickel-Slag Powder

2021 ◽  
Vol 11 (3) ◽  
pp. 1037
Author(s):  
Se-Jin Choi ◽  
Ji-Hwan Kim ◽  
Sung-Ho Bae ◽  
Tae-Gue Oh
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Construction Industry ◽  
Bituminous Coal ◽  
Raw Materials ◽  
Drying Shrinkage ◽  
The Other ◽  
Test Results ◽  
Slag Powder ◽  
Ferronickel Slag

In recent years, efforts to reduce greenhouse gas emissions have continued worldwide. In the construction industry, a large amount of CO2 is generated during the production of Portland cement, and various studies are being conducted to reduce the amount of cement and enable the use of cement substitutes. Ferronickel slag is a by-product generated by melting materials such as nickel ore and bituminous coal, which are used as raw materials to produce ferronickel at high temperatures. In this study, we investigated the fluidity, microhydration heat, compressive strength, drying shrinkage, and carbonation characteristics of a ternary cement mortar including ferronickel-slag powder and fly ash. According to the test results, the microhydration heat of the FA20FN00 sample was slightly higher than that of the FA00FN20 sample. The 28-day compressive strength of the FA20FN00 mix was approximately 39.6 MPa, which was higher than that of the other samples, whereas the compressive strength of the FA05FN15 mix including 15% of ferronickel-slag powder was approximately 11.6% lower than that of the FA20FN00 mix. The drying shrinkage of the FA20FN00 sample without ferronickel-slag powder was the highest after 56 days, whereas the FA00FN20 sample without fly ash showed the lowest shrinkage compared to the other mixes.

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 Strength and abrasion performance of recycled aggregate based geopolymer concrete

2021 ◽  
Author(s):  
Asfaw Mekonnen LAKEW ◽  
Mukhallad M. AL-MASHHADANI ◽  
Orhan CANPOLAT
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Coarse Aggregate ◽  
Steel Fiber ◽  
Splitting Tensile Strength ◽  
Partial Replacement ◽  
Geopolymer Concrete ◽  
Recycled Coarse Aggregate ◽  
One Year

This experimental work evaluated geopolymer concrete containing fly ash and slag by partial replacement of natural coarse aggregate (NCA) with recycled coarse aggregate (RCA) to manufacture environmental-friendly concrete. The proportion of recycled aggregates considered consists of 10%, 20%, 30%, and 40% of the total coarse aggregate amount. Also, a steel fiber ratio of 0.3% was utilized. The mechanical properties and abrasion resistance of fly ash/slag-based geopolymer concrete were then assessed. Majorly, the mechanical strength of the concrete samples decreased by the increase of RCA content. The geopolymer concrete with 40% RCA gave 28.3% lesser compressive strength and 24% lower splitting tensile strength than NCA concrete at one year. Also, the flexural strength of concrete specimens was reduced by 35% (from 5.34MPa to 3.5MPa) with the incorporation of 40% RCA. The incorporation of 30% RCA caused 23% and 22.6% reduction in compressive strength at 56 days and one year, respectively. The flexural and splitting tensile strength of the specimens was not significantly reduced (less than 10%) with the inclusion of a recycled coarse aggregate ratio of up to 30%. Furthermore, the abrasion wear thickness of every concrete sample was less than 1mm. RCA inclusion of 20% produced either insignificant reduction or better strength results compared to reference mixtures. As a result, it was considered that the combination of 0.3% steel fiber and 20% recycled coarse aggregate in fly ash/slag-based geopolymer concrete leads to an eco-friendly concrete mix with acceptable short and long-term engineering properties that would lead to sustainability in concrete production and utilization sector.

EVALUATION OF SHRINKAGE AND DURABILITY OF GEOPOLYMER CONCRETE USING F-CLASS COAL ASHES

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Gum Sung Ryu ◽  
Kyung Taek Koh ◽  
Gi Hong An ◽  
Jang Hwa Lee
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Bottom Ash ◽  
Drying Shrinkage ◽  
Geopolymer Concrete ◽  
Cement Concrete ◽  
Fly Ash Concrete ◽  
Coal Ashes

This paper evaluates the strength, shrinkage and durability characteristics of concrete using 100% fly ash and bottom ash as binder. It is seen that the compressive strength of activated fly ash and bottom ash concrete reaches respectively 25 MPa and 30 MPa, and that the change in strength is insignificant as per the content of bottom ash powder. Moreover, the total amount of shrinkage of the activated bottom ash concrete appears to be larger than that of the activated fly ash concrete. In addition, the drying shrinkage and durable performance of the activated ash geopolymer concrete is verified to be superior to that of ordinary cement concrete.

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.

Effects of Change in Fineness of Fly Ash on Air-Entrained Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 2195-2199 ◽  
Author(s):  
Hong Zhu Quan ◽  
Hideo Kasami
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Laboratory Experiments ◽  
Drying Shrinkage ◽  
Test Results ◽  
Air Entrained Concrete

In order to make clear of the effects of the change in fineness of fly ash on air-entrained concrete, 2 series of laboratory experiments were carried out using 6 kinds fly ash with the specific surface area in the range from 2500 to 4400cm2/g. The test results indicated higher slump and lower air-entraining content and higher dosage of air-entraining agent for fly ash with higher specific surface area. Compressive strength was found to increase with the increases of specific surface area of fly ash, while drying shrinkage and carbonation were found to show different tendency with change in fineness of fly ash.

Time-Dependent Properties of Lightweight Concrete Using Sedimentary Lightweight Aggregate

2010 ◽  
Vol 168-170 ◽  
pp. 2235-2240
Author(s):  
How Ji Chen ◽  
Wen Po Tsai ◽  
Ming Der Yang
Keyword(s):  
Lightweight Concrete ◽  
Drying Shrinkage ◽  
Lightweight Aggregate ◽  
Normal Weight ◽  
Time Dependent ◽  
Test Results ◽  
Fine Sediments ◽  
Normal Weight Concrete ◽  
Shrinkage And Creep ◽  
Shihmen Reservoir

A kind of lightweight aggregate (LWA) has been successfully developed in Taiwan, which was made by expanding under heat fine sediments dredged from the Shihmen Reservoir. In this study the performances of concrete made from the aforementioned LWA were tested and compared with those of the companion normal weight concrete (NC). The test results show that the so produced lightweight concrete (LWAC) exhibited a comparable time-dependent properties (i.e., compressive strength, elastic modulus, drying shrinkage, and creep) as compared with those of the companion NC. Based on the results, it can be concluded that the use of prewetted LWAs and the incorporation of pozzolan materials can effectively control the drying shrinkage of LWAC. The specific creep of the LC mixture was obviously higher than that of the NC mixture at the same curing time.

Fracture Parameters of Fly Ash and GGBS Based Geopolymer Concrete

2015 ◽  
Vol 764-765 ◽  
pp. 1090-1094
Author(s):  
Tippabhotla D. Gunneswara Rao ◽  
P. Alfrite ◽  
G. Mallikarjuna Rao ◽  
Mudimby Andal
Keyword(s):  
Fly Ash ◽  
Construction Material ◽  
Bending Test ◽  
Geopolymer Concrete ◽  
Test Results ◽  
Conventional Concrete ◽  
Three Point Bending ◽  
Beam Depth ◽  
New Construction ◽  
Source Materials

Geopolymer concrete (GPC) is a new construction material in which cement is totally replaced by calcined source materials fly ash and GGBS. Geopolymer utilization reduces or eliminates the use of cement whose production produces a lot of carbon dioxide. Usually fly ash as a source material for the geopolymer. The behavior of GPC has to be studied in detail to check its suitability in construction industry. In the present study, the fracture behavior of geopolymer concrete is investigated and compared. Three-point bending test on notched prisms with a/d (notch depth/beam depth) ratios 0.1, 0.15, 0.2 are considered. The values of Critical load, fracture toughness, fracture energy and ductility are presented. The test results of total of 27prisms, 6cubes, 18 cylinders with M30 grade geopolymer concrete and conventional concrete (OPC) of same grade are presented in this paper. The test results indicated that the characteristic length of GPC is about 25% more than that of conventional concrete.

Sign in / Sign up

Export Citation Format

Share Document