Properties of Geopolymer Mortar Subjected to High Temperature

2020 ◽  
Vol 858 ◽  
pp. 193-198
Author(s):  
Ali Kadhim Ibrahim ◽  
Osamah AL-Kerttani ◽  
Suha Rasheed Abbas
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Silica Fume ◽  
Splitting Tensile Strength ◽  
Geopolymer Concrete ◽  
Burning Temperature

Geopolymer concrete was presented to produce alternative binder to cement. This study considered the influence of silica fume on the properties of metakaolin based geopolymer mortar exposed to high temperature up to 800 °C. Five mortar mixes were used with silica fume replacing level of 0, 10, 20, 30 and 40% of weight of metakaolin. The results demonstrated that the compressive and splitting tensile strength increased with increasing the silica fume replacing level up to 40% of weight of metakaolin for all burning temperature and the absorption was decreased with it. The outcomes also demonstrated that for the same mix the compressive and splitting tensile strength improved with increment burning temperature up to 400 °C and reduced with increasing the temperature above it until 800 °C.

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.

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 Mechanical Effect of Steel Fiber on the Cement Replacement Materials of Self-Compacting Concrete

Fibers ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 36 ◽  
Author(s):  
Hisham Alabduljabbar ◽  
Rayed Alyousef ◽  
Fahed Alrshoudi ◽  
Abdulaziz Alaskar ◽  
Ahmed Fathi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Silica Fume ◽  
Steel Fiber ◽  
Mechanical Effect ◽  
Splitting Tensile Strength ◽  
Self Compacting Concrete ◽  
Cement Replacement ◽  
Filling Ability ◽  
Concrete Mix

The behaviors of the fresh and mechanical properties of self-compacting concrete (SCC) are different from those of normal concrete mix. Previous research has investigated the benefits of this concrete mix by incorporating different constituent materials. The current research aims to develop a steel fiber reinforcement (SFR)‒SCC mixture and to study the effectiveness of different cement replacement materials (CRMs) on the fresh and mechanical properties of the SFR‒SCC mixtures. CRMs have been used to replace cement content, and the use of different water/cement ratios may lower the cost of CRMs, which include microwave-incinerated rice husk ash, silica fume, and fly ash. Fresh behavior, such as flow and filling ability and capacity segregation, was examined by a special test in SCC on the basis of their specifications. Moreover, compressive and splitting tensile strength tests were determined to simulate the hardened behavior for the concrete specimens. Experimental findings showed that, the V-funnel and L-box were within the accepted range for SCC. Tensile and flexural strength increases upon the use of 10% silica fume were found when compared with other groups; the ideal percentage of steel fiber that should be combined in this hybrid was 2% of the total weight of the binder. Overall, steel fibers generated a heightened compressive and splitting tensile strength in the self-compacting concrete mixes.

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.

Development of High Performance Concrete Containing Admixture in Nuclear Power Plants

2013 ◽  
Vol 357-360 ◽  
pp. 1062-1065 ◽  
Author(s):  
Jeong Eun Kim ◽  
Wan Shin Park ◽  
Song Hui Yun ◽  
Do Gyeum Kim ◽  
Jea Myoung Noh
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Blast Furnace ◽  
Fly Ash ◽  
Silica Fume ◽  
Modulus Of Elasticity ◽  
Blast Furnace Slag ◽  
High Performance ◽  
Splitting Tensile Strength ◽  
Furnace Slag

This paper presents the results of an experimental study on the compressive strength, splitting tensile strength and modulus of elasticity characteristics of high performance concrete. These tests were carried out to evaluate the mechanical properties of HPC for up to 7 and 28 days. Mixtures were prepared with water to binder ratio of 0.40. Two mixtures were containing fly ash at 25%, silica fume at 5% cement replacement, respectively. Another mixture was contains blast furnace slag and fly ash at 25%. Three standard 100¥a200 cylinder specimens were prepared. HPC showed improvement in the compressive strength and splitting tensile strength when ordinary Portland cement was replaced with silica fume. Compare with specimens FA25 and BS25FA25, specimen SF5 showed much more modulus of elasticity. It shows that the use of the blast furnace slag of 25% and fly ash of 25% cement replacement has caused a small increase in compressive strength and splitting tensile strength and modulus of elasticity compared to the only use of fly ash of 25% at 28days. The results indicated that the use of blast furnace slag or silica fume provided the good performance compare to fly ash when the mechanical properties of the high performance concretes were taken into account.

Study on Splitting Tensile Strength of Shotcret Layer of High Temperature Tunnel

2012 ◽  
Vol 594-597 ◽  
pp. 1169-1173
Author(s):  
Yan Zhang ◽  
Ning Li ◽  
Hao Bo Zhang
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Layer Structure ◽  
Splitting Tensile Strength ◽  
Engineering Practice ◽  
Kunlun Mountains ◽  
Heating Device ◽  
Significant Temperature ◽  
The Stability ◽  
West Kunlun

The high-temperature tunnel at Buren mouth - kongur Hydropower in West Kunlun Mountains of Xinjiang, China exist significant temperature differences phenomenon, which affects the stability of the shotcrete layer in tunnel. Combining with on-site engineering practice, the insulation heating device is designed. The laboratory splitting tensile strength test is carried out on polyester concrete, polypropylene concrete, polyacrylonitrile concrete and ordinary concrete with thermal heating device at 25°C-90°C. The splitting tensile strength changes of concretes affected by temperature difference are analyzed. The results supply a directly guidance to the design of the concrete sprayed layer structure of high-temperature tunnel.

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.

An Experimental Study on Evaluation of Mechanical Properties in High Performance Concrete Using Admixture

2013 ◽  
Vol 372 ◽  
pp. 231-234
Author(s):  
Jeong Eun Kim ◽  
Wan Shin Park ◽  
Nam Yong Eom ◽  
Sun Woong Kim ◽  
Do Gyeum Kim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Silica Fume ◽  
Modulus Of Elasticity ◽  
High Performance ◽  
High Performance Concrete ◽  
Splitting Tensile Strength ◽  
Experimental Investigations ◽  
Binder Ratio

In this study, some experimental investigations on the development of mechanical properties with age of high performance concrete (HPC) incorporated with blast furnace slag with fly ash or silica fume have been reported. Four different blended HPC were prepared in 0.40 water-binder ratio. At every four mixtures, the compressive strength, splitting tensile strength and modulus of elasticity at 7 and 28 days have been observed for HPC developments. Consequently, only replacement of silica fume significantly increases the mechanical properties in terms of compressive strength, splitting tensile strength and modulus of elasticity.

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