scholarly journals High volume fly ash mortar containing nano-calcium carbonate as a sustainable cementitious material: microstructure and strength development

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Huashan Yang ◽  
Yujun Che ◽  
Faguang Leng
Keyword(s):  
Fly Ash ◽  
Calcium Carbonate ◽  
High Volume ◽  
Cementitious Material ◽  
Strength Development ◽  
Material Microstructure ◽  
High Volume Fly Ash

scholarly journals Effect of High Volume Flyash on Fiber Strengthened Concrete

2019 ◽  
Vol 8 (11) ◽  
pp. 2467-2473
Keyword(s):  
Fly Ash ◽  
Basalt Fiber ◽  
High Volume ◽  
Cementitious Material ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fly Ash Concrete ◽  
High Volume Fly Ash ◽  
Test Outcomes ◽  
The Ideal

Fly Ash (FA) is being utilized as a pozzolonic material when connected as a valuable cementitious material for cement. Fiber Reinforced Concrete (FRC) is a solid having sinewy material which manufactures its helper uprightness. It contains short discrete strands that are reliably scattered and aimlessly arranged. The expansion of Steel Fibers in cement essentially expands its flexural strength; vitality retention limit, malleable conduct before a definitive disappointment, decreased breaking, and improved toughness. Basalt fiber is an elite non-metallic fiber produced using basalt shake dissolved at high temperature. In High Volume Fly Ash Concrete (HVFAC), increment in the amount of cementitious C-S-H stage and calcium aluminium hydrates improves the long haul qualities and lessens the porousness. Therefore improves the solidness properties. The primary point of this examination is to consider the mechanical properties of HVFA cement fortified with half and half filaments. Tests are directed according to the Indian norms and test outcomes are broke down and contrasted and the control example that contains crossover fiber fortified HVFA concrete, HVFA concrete without any strands (non-stringy cement), and Conventional cement. With the fitting understanding of the got outcomes, it is possible to decide the ideal fiber rate in HVFA concrete.

Nanosilica Activated High Volume Fly Ash Concrete: Effects on Selected Properties

2016 ◽  
Vol 722 ◽  
pp. 157-162 ◽  
Author(s):  
Martin Labaj ◽  
Rudolf Hela ◽  
Iveta Hájková
Keyword(s):  
Fly Ash ◽  
Raw Materials ◽  
Water Pressure ◽  
Construction Material ◽  
High Volume ◽  
Strength Development ◽  
Early Age ◽  
Fly Ash Concrete ◽  
High Volume Fly Ash ◽  
Static And Dynamic Moduli

By volume, there is no other material used as much as concrete. Its mechanical properties, durability and favorable price makes concrete the perfect construction material. In last few decades, we are seeing a growing trend of partial Portland cement’s replacement with secondary raw materials, most commonly with fly ash. So-called high volume fly ash (HVFA) concretes usually contains over 50% of it. While HVFA concrete’s long-term properties and price are improved over the classical one, its early age properties are often affected negatively. Here, a highly reactive pozzolans enters the scene. Materials like microsilica and metakaolin are known to accelerate concrete’s strength development and improve early age characteristics. In this paper, nanosilica is used for this purpose. These SiO2 nanoparticles possesses a much higher surface area and thus reactivity. Three mixtures with 0, 40 a 60% portland cement’s replacement with fly ash were prepared and tested with and without addition of small amount of nanosilica. Effects on compressive strength, static and dynamic moduli of elasticity and resistivity against water pressure were observed. Results clearly demonstrates that even with dosage in the range of tenths of percent, nanosilica can significantly improve concrete’s properties.

Effect of Nano Silica and Ultrafine Fly Ash on Compressive Strength of High Volume Fly Ash Mortar

2013 ◽  
Vol 368-370 ◽  
pp. 1061-1065 ◽  
Author(s):  
Steve W.M. Supit ◽  
Faiz U.A. Shaikh ◽  
Prabir K. Sarker
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Volume ◽  
Partial Replacement ◽  
Strength Development ◽  
Test Results ◽  
X Ray Diffraction ◽  
Nano Silica ◽  
High Volume Fly Ash ◽  
Class F Fly Ash

This paper evaluates the effect of Ultrafine Fly Ash (UFFA) and nanoSilica (NS) on compressive strength of high volume fly ash (HVFA) mortar at 7 days and 28 days. Three series of mortar mixes are considered in the first part of this study. In the first series the effect of high content of class F fly ash as partial replacement of cement at 40, 50 and 60% (by wt.) are considered. While in the second and third series, the UFFA and NS are used as partial replacement of cement at 5%, 8%, 10%, 12% and 15% and 1%, 2%, 4%, 6% and 8% (by wt.) of cement, respectively. The UFFA and the NS content which exhibited highest compressive strength in the above series are used in the second part where their effects on the compressive strength of HVFA mortars are evaluated. Results show that the mortar containing 10% UFFA as partial replacement of cement exhibited the highest compressive strength at both 7 and 28 days among all UFFA contents. Similarly, the mortar containing 2% NS as partial replacement of cement exhibited the best performance. Interestingly, the use of UFFA in HVFA mortars did not improve the compressive strength. However, the use of 2% and 4% NS showed improvement in the compressive strength of HVFA mortar containing 40% and 50% fly ash at both ages. The effects of NS and UFFA on the hydration and strength development of HVFA mortar is also evaluated through X-Ray Diffraction (XRD) test. Results also show that the UFFA and NS can significantly reduce the calcium hydroxide (CH) in HVFA mortars.

An Assessment of Characteristics of Densified High-Performance Concrete Incorporating High Volume Fly Ash

2018 ◽  
Vol 923 ◽  
pp. 105-109
Author(s):  
Trong Phuoc Huynh ◽  
Chao Lung Hwang
Keyword(s):  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
High Volume ◽  
Strength Development ◽  
Hardened Concrete ◽  
Microstructural Characteristics ◽  
Design Algorithm ◽  
High Volume Fly Ash ◽  
Maximum Compressive Strength

The present study evaluates the mechanical-microstructural characteristics of the densified high-performance concrete (HPC) incorporating high volume fly ash (FA). The densified mixture design algorithm (DMDA) technology was applied to design the concrete proportions. The effects of various FA contents on both fresh and hardened concrete were investigated. A scanning electron microscope (SEM) was used to observe the microstructure of the concrete samples. The effectiveness of using DMDA in mix deign was also discussed in this study. As the experimental results, the FA content was found to affect the concrete properties significantly. The maximum compressive strength value of 65.1 MPa was obtained at the concrete samples containing 40% FA. Additionally, the 40% FA samples exhibited a denser microstructure as compared to the others. Generally, all of the tested concrete samples exhibited good performance in terms of workability, strength development, water absorption, and porosity. The results of this study further show the effectiveness of using DMDA technology in proportioning of the concrete mixture.

scholarly journals Enhancing the Microstructure and Sustainability of Ultra-High-Performance Concrete Using Ultrafine Calcium Carbonate and High-Volume Fly Ash under Different Curing Regimes

2021 ◽  
Vol 13 (7) ◽  
pp. 3900
Author(s):  
Norzaireen Azmee ◽  
Yassir M. Abbas ◽  
Nasir Shafiq ◽  
Galal Fares ◽  
Montasir Osman ◽  
...  
Keyword(s):  
Fly Ash ◽  
Calcium Carbonate ◽  
High Performance ◽  
High Performance Concrete ◽  
High Volume ◽  
Partial Substitution ◽  
High Volume Fly Ash ◽  
Curing Methods ◽  
Mechanical And Microstructural Properties ◽  
Curing Regimes

In current practice, the performance-based concrete mix (PBCM) approach has become quite popular because it enhances the quality of materials that are fundamentally necessary for a particular situation. In the present study, experimental analysis is performed to determine the optimal mechanical properties and microstructural characteristics of concrete for sustainable development and cost effectiveness. Specifically, a mixture of high-volume fly ash (FA) and ultrafine calcium carbonate (UFCC) is investigated as a partial substitution of cement. For optimizing the concrete’s performance, various curing regimes are applied to evaluate the best conditions for obtaining ideal mechanical and microstructural properties. The results show that concrete containing 10% UFCC with a mean particle size of 3.5 µm blended with 40% FA yielded the best performance, with an enhancement of 25% in the compressive strength in the early age. Moreover, the UFCC improved the compactness and refined the interstitial transition zone (ITZ). However, the effects of the different curing methods on the concrete’s strength were insignificant after 28 days.

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