scholarly journals Preparation of Green Low Strength Mixture for Foundation Reinforcement Treatment by Using Fly Ash and Waste Coal Gangue

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 664 ◽  
Author(s):  
Linhao Li ◽  
Guangcheng Long ◽  
Kunlin Ma ◽  
Hongwei Ma ◽  
Wenbing Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
High Performance ◽  
Acid Resistance ◽  
High Volume ◽  
Waste Recycling ◽  
Coal Gangue ◽  
Dynamic Shear Modulus ◽  
Durability Performance

Effective foundation reinforcement treatment is essential for modern large and complex infrastructure, while it is significant for developing new green high-performance materials for foundation reinforcement. This study investigates a new green concrete by using high volume fly-ash and coal gangue aggregates, which is expected to apply for foundation treatment of modern infrastructure with high loading-bear ability. In this experiment, 12 mix proportions of fly ash coal gangue mixture (the material name, abbreviated FGM) were designed, and its mechanical properties and durability performance were investigated. The mechanical properties of FGM include compressive strength, dynamic elastic modulus, dynamic shear modulus, Poisson’s ratio, and the stress–strain behaviors. The durability performance was evaluated by the parameters of acid resistance, which simulated an acid circumstance. After that, the environmental effects about carbon emission of this material were also investigated. Results show that the FGM with 84.6% wastes utilizing rate is a cost-effective material for foundation reinforcing treatment. Its compressive strength at 28 days and 60 days can reach more than 8 MPa and 10 MPa, respectively. After being immersed in the acid environment for 140 days, the mass loss (%) of the material could be under 3.5%. The greenness shows that the e-CO2 indices of FGM are lower than 20 kg/MPa·m3, and the e-energy indices are at below 150 MJ/MPa·m3. FGM has the advantages of acid resistance, waste recycling, and lower carbon emissions than the previous methods for foundation improvement.

Experimental Study on Workability and Strength of Green High Performance Concrete with High Volume Fly Ash

2013 ◽  
Vol 859 ◽  
pp. 52-55 ◽  
Author(s):  
Yong Qiang Ma
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
High Volume ◽  
Ash Content ◽  
Splitting Tensile Strength ◽  
Binder Ratio ◽  
Water Binder Ratio

A great deal of experiments have been carried out in this study to reveal the effect of the water-binder ratio and fly ash content on the workability and strengths of GHPC (green high performance concrete). The workability of GHPC was evaluated by slump and slump flow. The strengths include compressive strength and splitting tensile strength. The results indicate that the increase of water-binder ratio can improve the workability of GHPC, however the strengths of GHPC were decreased with the increase of water-binder ratio. When the fly ash content is lower than 40%, the increase in fly ash content has positive effect on workability of GHPC, while the workability begins to decrease after the fly ash content is more than 40%. The addition of fly ash in GHPC has adverse effect on the strengths, and there is a tendency of decrease in the compressive strength and splitting tensile strength of GHPC with the increase of fly ash content.

FLY ASH AND BAGASSE FIBER INFLUENCES ON MECHANICAL PROPERTIES OF GREEN HYBRID FIBER-REINFORCED CEMENTITIOUS COMPOSITES

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
He Tian ◽  
Y. X. Zhang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
High Volume ◽  
Fiber Content ◽  
Modulus Of Rupture ◽  
Fiber Reinforced ◽  
Cement Ratio ◽  
High Volume Fly Ash ◽  
Bagasse Fiber

In this paper, a new green fiber-reinforced cementitious composite containing high volume fly ash and hybrid steel and bagasse fibers is developed. Eco-friendly bagasse fibers from industrial waste and steel fibers are used to improve the mechanical behavior of the new composite, and high-volume fly ash is used to decrease the usage of cement in order to be more environmentally friendly. The influence of the fiber content and fly ash/cement ratio on the mechanical properties of the composite is investigated through the study of the mechanical properties of the new composite, such as compressive strength, modulus of elasticity, and modulus of rupture. It is found that compressive strength, Young's modulus of the composite, decreases with the increase of the fly ash/cement ratio and bagasse fiber content. However, the modulus of rupture of the composite increases firstly with bagasse fiber content, and decreases when bagasse fiber content reaches 3% by volume.

Influence of Fly Ash on the Mechanical Properties of Engineered Cementitious Composites Cured at High Temperature

2010 ◽  
Vol 113-116 ◽  
pp. 1293-1296
Author(s):  
Yu Zhu ◽  
Ying Zi Yang ◽  
Hong Wei Deng ◽  
Yan Yao
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
High Volume ◽  
Bending Test ◽  
Cementitious Composites ◽  
Test Results ◽  
Four Point Bending ◽  
High Volume Fly Ash ◽  
Compressive Strength Test

In order to investigate the mechanical properties of cementitious composites (ECC) cured at 60°C, four-point bending test and compressive strength test are employed to analyze the effect of fly ash on the properties of ECC. The replacement ratio of cement with fly ash is 50%, 70% and 80%, respectively. The test results indicate that ECC with high volume fly ash still remain the characteristic of pseudo-strain hardening and the deflection of ECC increases remarkably by adding more fly ash. The observations of ECC indicate that the crack width is relatively smaller for higher volume fly ash ECC. Meanwhile, compressive strength of ECC specimens with 80% fly ash can reach to 70MPa. This is helpful to produce precast ECC with high volume of fly ash.

scholarly journals Compressive Strength Development of High-Volume Fly Ash Ultra-High-Performance Concrete under Heat Curing Condition with Time

2020 ◽  
Vol 10 (20) ◽  
pp. 7107
Author(s):  
Pham Sy Dong ◽  
Nguyen Van Tuan ◽  
Le Trung Thanh ◽  
Nguyen Cong Thang ◽  
Viet Hung Cu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
High Volume ◽  
Strength Development ◽  
Ultra High Performance Concrete ◽  
Heat Curing ◽  
Compressive Strength Development ◽  
Curing Condition

This research investigated the effect of fly ash content on the compressive strength development of ultra-high-performance concrete (UHPC) at different curing conditions, i.e., the standard curing condition and the heat curing. A total of 20 mixtures were prepared to cast specimens to measure the compressive strength at different ages from 3 days to 180 days. Additionally, 300 specimens were prepared to estimate the appropriate heat curing period at the early ages in terms of enhancing the 28-day compressive strength of UHPC with high content of fly ash (FA). From the regression analysis using test data, empirical equations were formulated to assess the compressive strength development of UHPC considering the FA content and maturity function. Test results revealed that the preference of the addition of FA for enhancing the compressive strength of UHPC requires the early heat curing procedure which can be recommended as at least 2 days under 90 °C. Moreover, the compressive strength of UHPC with FA under heat curing mostly reached its 28-day strength within 3 days. The proposed models based on the fib 2010 model can be a useful tool to reliably assess the compressive strength development of UHPC with high-volume fly ash (HVFA) (up to 70% fly ash content) under a heat curing condition that possesses a different performance from that of normal- and high-strength concrete. When 50% of the cement content was replaced by FA, the embodied CO2 emission for UHPC mixture reduced up to approximately 50%, which is comparable to the CO2 emission calculated from the conventional normal-strength concrete.

scholarly journals Effects of Kaolin Addition on Mechanical Properties for Cemented Coal Gangue-Fly Ash Backfill under Uniaxial Loading

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3693
Author(s):  
Faxin Li ◽  
Dawei Yin ◽  
Chun Zhu ◽  
Feng Wang ◽  
Ning Jiang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Uniaxial Compressive Strength ◽  
Shear Failure ◽  
Coal Gangue ◽  
Tensile Failure ◽  
Peak Strain ◽  
Local Shear

In this investigation, six groups of cemented coal gangue-fly ash backfill (CGFB) samples with varying amounts of kaolin (0, 10, 20, 30, 40, and 50%) instead of cement are prepared, and their mechanical properties are analyzed using uniaxial compression, acoustic emission, scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The uniaxial compressive strength, peak strain, and elastic modulus of CGFB samples decreased with the kaolin content. The average uniaxial compressive strength, elastic modulus, and peak strain of CGFB samples with 10% amount of kaolin are close to that of CGFB samples with no kaolin. The contribution of kaolin hydration to the strength of CGFB sample is lower than that of cement hydration, and the hydration products such as ettringite and calcium-silicate-hydrate gel decrease, thereby reducing strength, which mainly plays a role in filling pores. The contents of kaolin affect the failure characteristics of CGFB samples, which show tensile failure accompanied by local shear failure, and the failure degree increases with the kaolin content. The porosity of the fracture surface shows a decreasing trend as a whole. When the amount of kaolin instead of cement is 10%, the mechanical properties of CGFB samples are slightly different from those of CGFB samples without kaolin, and CGFB can meet the demand of filling strength. The research results provide a theoretical basis for the application of kaolin admixture in fill mining.

Utilization of Fly Ash in High Performance Floor Screed Based on Cement and its Influence on Physical Mechanical Properties

2016 ◽  
Vol 865 ◽  
pp. 201-205 ◽  
Author(s):  
Michaela Fiedlerová ◽  
Rostislav Drochytka ◽  
Pavel Dohnálek
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Water Absorption ◽  
Bulk Density ◽  
High Performance ◽  
Power Plants ◽  
High Strength ◽  
Partial Replacement ◽  
Reference Samples

This paper deals with the evaluation of a partial replacement of cement by Czech fly ash in high strength floor screed in dosage of 10, 20, 30 and 40% and the assessment of the physical-mechanical properties such as compressive strength, water absorption and bulk density. Used fly ashes are from power plants Počerady, Opatovice and Tušimice. The experimental study showed that the use of Czech fly ash improves the compressive strength. The bulk density decreases and therefore water absorption increases. Reference samples become clearly the lowest compressive strength at age of 28 days (fc28). A significant increase in compressive strength (fc28) was observed in case of mix design with addition of 10% and 20% of fly ash Tušimice (10%ETU, 20%ETU) and 20% and 30% of fly ash Počerady (20%EPC, 30%EPC). The addition of 20% of fly ash Počerady (20%EPC) has noticeable influence on short-term compressive strength (measured at the age of 24 hours).

scholarly journals Mix design of high-volume fly ash ultra high performance concrete

2021 ◽  
Vol 15 (4) ◽  
pp. 197-208
Author(s):  
Nguyen Van Tuan ◽  
Pham Sy Dong ◽  
Le Trung Thanh ◽  
Nguyen Cong Thang ◽  
Yang Keun Hyeok
Keyword(s):  
Heat Treatment ◽  
Compressive Strength ◽  
Fly Ash ◽  
Co2 Emissions ◽  
High Performance ◽  
High Performance Concrete ◽  
High Volume ◽  
Mix Design ◽  
Ultra High Performance Concrete ◽  
High Volume Fly Ash

The addition of supplementary cementitious materials (SCMs) to replace cement, especially with a high volume (> 50%), is an effective way to reduce the environmental impact due to the CO2 emissions generated in the production of ultra-high performance concrete (UHPC). Unfortunately, no official guidelines of UHPC using a high volume of SCMs have been published up to now. This paper proposes a new method of mix design for UHPC using high volume fly ash (HVFA), that is referred to the particle packing optimization of the Compressive Packing Model proposed by F. de Larrard. This proposed method also considers the heat treatment curing duration to maximize the compressive strength of HVFA UHPC. The experimental results using this proposed mix design method show that the optimum fly ash content of 50 wt.% of binder can be used to produce HVFA UHPC with a compressive strength of over 120 MPa and 150 MPa under standard curing and heat treatment, respectively. Moreover, the embodied CO2 emissions of UHPC reduces 56.4% with addition of 50% FA.

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