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.

Experimental Study of Splitting Tensile Strength of Polymer Resin Grout with Fly Ash

2015 ◽  
Vol 789-790 ◽  
pp. 38-42
Author(s):  
Nuria S. Mohammed ◽  
Ahmed Baharuddin Abd Rahman ◽  
Nur Hafizah A. Khalid ◽  
Musaab Ahmed
Keyword(s):  
Experimental Study ◽  
Tensile Strength ◽  
Fly Ash ◽  
High Strength ◽  
Ash Content ◽  
Splitting Tensile Strength ◽  
Test Results ◽  
River Sand ◽  
Polymer Resin ◽  
Bonding Material

Polymer resin grout can be used as bonding material for grouted sleeve connections This paper presents the experimental results on the effectiveness of fly ash as micro filler to the splitting tensile strength of polymer grout. In addition, the cement grout that is usually used as bonding material had been tested for comparison. Eleven proportions, of fly ash as the filler and polymer as binder, were tested with the binder to filler volume ratios of 1:1 and 1:1.5. The test results revealed that fly ash can be used as a micro-filler material to partially replace ordinary river sand in polymer resin grout. The splitting tensile strength of the polymer grout increases with the increase of fly ash contents. However, for higher level of fly ash of more than 22%, the splitting tensile strength deteriorated. For binder: filler ratio of 1:1, the optimum fly ash content of 22% gave the maximum splitting strength of 17.62 MPa, which can be considered acceptable for producing grout with high strength bonding material.

scholarly journals Use of waste paper ash or wood ash as substitution to fly ash in production of geopolymer concrete

2021 ◽  
Vol 30 (3) ◽  
pp. 464-476
Author(s):  
Haider Owaid ◽  
Haider Al-Baghdadi ◽  
Muna Al-Rubaye
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Sodium Hydroxide ◽  
Wood Ash ◽  
Splitting Tensile Strength ◽  
Waste Paper ◽  
Geopolymer Concrete

Large quantities of paper and wood waste are generated every day, the disposal of these waste products is a problem because it requires huge space for their disposal. The possibility of using these wastes can mitigate the environmental problems related to them. This study presents an investigation on the feasibility of inclusion of waste paper ash (WPA) or wood ash (WA) as replacement materials for fly ash (FA) class F in preparation geopolymer concrete (GC). The developed geopolymer concretes for this study were prepared at replacement ratios of FA by WPA or WA of 25, 50, 75 and 100% in addition to a control mix containing 100% of FA. Sodium hydroxide (NaOH) solutions and sodium silicate (Na2SiO3) are used as alkaline activators with 1M and 10M of sodium hydroxide solution.The geopolymer concretes have been evaluated with respect to the workability, the compressive strength, splitting tensile strength and flexural strength. The results indicated that there were no significant differences in the workability of the control GC mix and the developed GC mixes incorporating WPA or WA. Also, the results showed that, by incorporating of 25–50% PWA or 25% WA, the mechanical properties (compressive strength, splitting tensile strength and flexural strength) of GC mixes slightly decreased. While replacement with 75–100% WPA or with 50–100% WA has reduced these mechanical properties of GC mixes. As a result, there is a feasibility of partial replacement of FA by up to 50% WPA or 25% WA in preparation of the geopolymer concrete.

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.

Properties of slag geopolymer concrete modified with fly ash and silica fume

2021 ◽  
Author(s):  
Hafez Elsayed Elyamany ◽  
Abd Elmoaty Mohamed Abd Elmoaty ◽  
Abdul Rahman Ahmed Diab
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Setting Time ◽  
Splitting Tensile Strength ◽  
Geopolymer Concrete ◽  
Initial Setting Time ◽  
Initial Setting ◽  
Additional Water

This research focused on the role of fly ash and silica fume on slag geopolymer concrete through investigating workability (slump, and slump loss), initial setting time, final setting time, and mechanical properties of slag geopolymer concrete, S-GPC, (compressive strength, splitting tensile strength, modulus of elasticity) in addition to SEM (Scanning electron microscope), and X-Ray analysis. The considered variables included, fly ash (FA) content as a replacement of ground granulated blast furnace slag (GS) (0, 10, 20, 30, and 40 %), presence of silica fume (SF) as a replacement of slag, concentration of sodium hydroxide, NaOH, (molarity: 10M, 16M, and 18M), additional water content (7.5,11,14, and 20 %), and curing type (thermal, air, and water curing). S-GPC yielded rapid stiffening and high slump loss with high mechanical properties. The use of silica fume or fly ash or a mix of them enhanced workability, decreased rate of slump loss, and delayed setting time. ACI 318 equation over estimates splitting tensile strength of FS-GPC.

Steel Reinforcement Corrosion in a Low Calcium Fly Ash Geopolymer Concrete

2016 ◽  
Vol 711 ◽  
pp. 943-949
Author(s):  
Mahdi Babaee ◽  
Arnaud Castel
Keyword(s):  
Fly Ash ◽  
Steel Corrosion ◽  
Test Methods ◽  
Geopolymer Concrete ◽  
Reinforcement Corrosion ◽  
Portland Cement Concrete ◽  
Electrochemical Test ◽  
Free Corrosion Potential ◽  
Low Calcium

Geopolymer concrete (GPC) has significant potential as a more sustainable, low-embodied carbon alternative for ordinary Portland cement concrete (PCC). However; as a rather new engineering material, there are some concerns over the durability aspects of geopolymeric binders. In this study, performance of chloride contaminated reinforced GPC specimens manufactured using low calcium fly ash is investigated by long-term monitoring of corrosion parameters such as free corrosion potential and polarization resistance. It was found that low calcium fly ash GPC can perform as well as PCC during the propagation phase of corrosion; although, some conventional reference values of corrosion parameters which are indicative of severity of the steel corrosion in PCC are not suitable for GPC. Additionally, commonly used electrochemical test methods are successfully employed to assess the degree of reinforcement corrosion in geopolymeric binders within an acceptable level of accuracy.

Study on Residual Splitting Tensile Strength of HFCC after High Temperature

2011 ◽  
Vol 243-249 ◽  
pp. 5067-5070 ◽  
Author(s):  
Fu Ping Jia ◽  
Yong Cheng ◽  
Yi Bing Sun ◽  
Yin Yu Wang ◽  
Hao Sun
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Fly Ash ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Splitting Tensile Strength ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Splitting Strength ◽  
Ordinary Portland Cement Concrete

This paper presents the results of the splitting tensile strength of high fly ash content concrete (HFCC) after high temperature and analysis the degraded rules of the residual splitting strength subjected to high temperature and the replacements of cement by fly ash. The specimens were prepared with three different replacements of cement by fly ash 30%, 40% and 50% by mass and were tested after exposure to high temperature 250, 450, 550 and 650°C and room temperature respectively, compared with ordinary Portland cement concrete. The results showed that the splitting tensile strength sensitively decreased with the high temperature increased. Furthermore, the presence of fly ash was effective for improvement of the relative strength. The relative residual splitting strength of fly ash concrete was higher than those of ordinary Portland cement concrete except 30% fly ash replacement. Based on the experiments results, the alternating simulation formula to determine the relationship among relative residual strength, high temperature and fly ash replacement is developed by using regression of results, which provides the theoretical basis for the evaluation and repair of HFCC after high temperature.

Unconfined Compressive and Splitting Tensile Strength of Dredged Sediments Stabilized with Cement and Fly Ash

2020 ◽  
Vol 856 ◽  
pp. 367-375
Author(s):  
Hatairat Poorahong ◽  
Nunthanis Wongvatana ◽  
Pitthaya Jamsawang ◽  
Kamolwan Lueprasert ◽  
Kullachai Tantayopin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fly Ash ◽  
Unconfined Compressive Strength ◽  
Building Materials ◽  
Mechanical Tests ◽  
Splitting Tensile Strength ◽  
Type I ◽  
Test Results ◽  
Dredged Sediments

The main objective of this study is to investigate the mechanical properties of dredged sediments, which are considered as waste from the process of removing sediments from the bottom of a dam's reservoir. The dredged sediments with stabilization can to be reused as construction and building materials in civil engineering works. The mechanical tests included unconfined compressive strength (UCS) and splitting tensile strength (STS) to understand the behavior of the dredged sediments stabilized with ordinary portland cement (OPC) type I and fly ash (FA). The overall test results indicated that OPC type I and FA were effective in stabilizing the sampled dredged sediments from two dams in northern Thailand. The stabilization with 10% FA content was found to be most effective for improving mechanical properties of the stabilized samples.

scholarly journals Mechanical Properties and Service Life Prediction of Modified Concrete Attacked by Sulfate Corrosion

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Min Zhang ◽  
Li-min Yang ◽  
Jin-Jun Guo ◽  
Wen-li Liu ◽  
Hong-li Chen
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Service Life ◽  
Life Prediction ◽  
Polypropylene Fiber ◽  
Splitting Tensile Strength ◽  
Test Results ◽  
Ordinary Concrete ◽  
Anticorrosion Properties

Under the condition of drying and wetting circulation, ordinary concrete, modified concrete containing fly ash, and double-admixture concrete containing fly ash and polypropylene fiber were corroded in the solution of Na2SO4 and (NH4)2SO4. The sulfate concentration of the solution was designed to be 1000 g/L. The compressive strength and splitting tensile strength of the concrete were tested after different number of drying and wetting cycles (0, 2, 4, 6, 8, and 10). The results indicate that the strength of concrete increases in the early stages of corrosion and decreases gradually later. The admixture significantly improves the resistance to sulfate erosion of the modified concrete, while polypropylene fiber plays a less important role on anticorrosion properties. When suffered 10 times of drying and wetting cycle, the compressive strength and splitting tensile strength of modified concrete increase by 28% and 19%, respectively. Based on the test results, the service life of the modified concrete corroded by sulfate was predicted.

scholarly journals Effect of Maximum Aggregate Size on the Bond Strength of Reinforcements in Concrete

2018 ◽  
Vol 8 (3) ◽  
pp. 2892-2896
Author(s):  
S. Iqbal ◽  
N. Ullah ◽  
A. Ali
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Bond Strength ◽  
Aggregate Size ◽  
Splitting Tensile Strength ◽  
Strength Calculation ◽  
Maximum Aggregate Size ◽  
Test Results ◽  
Tensile Stresses ◽  
Concrete Mix

The bond between reinforcements and concrete is the only mechanism that transfers the tensile stresses from concrete to reinforcements. Several factors including chemical adhesion, roughness and reinforcement interface and bar bearing affect the bond strength of reinforcements with concrete. This work was carried out considering another varying factor which is maximum aggregate size. Four mixes of concrete with similar compressive strengths but different maximum aggregate sizes of 25.4mm, 19.05mm, 12.7mm and 9.53mm were used with the same bar size of 16mm. Compressive strength, splitting tensile strength and bond strength for each concrete mix were studied. Test results depict a slight increase in compressive and splitting tensile strength with decrease in maximum aggregate size. The bond strength remained at the same level with decrease in maximum aggregate size except at maximum aggregate size of 9.53mm when there was a drop in bond strength, despite better compressive and splitting tensile strengths. ACI-318 and FIB-2010 codes equation for bond strength calculation work well only when the maximum aggregate size is 12.7mm and above. Therefore, maximum aggregate size is critical for bond strength when smaller size aggregates are used.

Sign in / Sign up

Export Citation Format

Share Document