scholarly journals Late Age Dynamic Strength of High-Volume Fly Ash Concrete with Nano-Silica and Polypropylene Fibres

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 243 ◽  
Author(s):  
Mohamed H. Mussa ◽  
Ahmed M. Abdulhadi ◽  
Imad Shakir Abbood ◽  
Azrul A. Mutalib ◽  
Zaher Mundher Yaseen
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Elevated Temperatures ◽  
High Volume ◽  
Nano Silica ◽  
Polypropylene Fibres ◽  
Fly Ash Concrete ◽  
High Volume Fly Ash ◽  
Dynamic Compressive Strength ◽  
Curing Age

The dynamic behaviour of high-volume fly ash concrete with nano-silica (HVFANS) and polypropylene fibres at curing ages of 7 to 90 days was determined by using a split Hopkinson pressure bar (SHPB) machine. At each curing age, the concrete samples were laboratory tested at different temperatures conditions under strain rates reached up to 101.42 s−1. At room temperature, the results indicated that the dynamic compressive strength of plain concrete (PC) was slightly higher than HVFANS concrete at early curing ages of 7 and 28 days, however, a considerable improvement in the strength of HVFANS concrete was noted at a curing age of 90 days and recorded greater values than PC owing to the increase of fly ash reactivity. At elevated temperatures, the HVFANS concrete revealed a superior behaviour than PC even at early ages in terms of dynamic compressive strength, critical strain, damage and toughness due to increase of nano-silica (NS) activity during the heating process. Furthermore, equations were suggested to estimate the dynamic increase factor (DIF) of both concretes under the investigated factors.

scholarly journals A Review on Early Age and Long-term Compressive Strength of High-volume Fly Ash Concrete

2018 ◽  
Vol 207 ◽  
pp. 01004
Author(s):  
Mu Li
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Volume ◽  
Partial Replacement ◽  
Early Age ◽  
Fly Ash Concrete ◽  
Power Stations ◽  
High Volume Fly Ash ◽  
Curing Age

Fly ash is a by-product of the combustion of the coal-fired electric power stations, and disposal of fly ash has been one of the environmental challenges. Much of the studies have been focused on the mechanical property of fly ash concrete. It is no doubt that the use of high-volume fly ash as a partial replacement of cement is also one of the effect way to utilize fly ash. It is known that the compressive strength of fly ash concrete is lower than that of ordinary concrete at early age, especially for high-volume fly ash concrete. It is urgent for engineers to consider the compressive strength of high-volume fly ash concrete at different curing age. In this review, the compressive strength of high-volume fly ash concrete in various literature was reported and then analyzed. Furthermore, the proposal of the utilization of high-volume fly ash concrete is provided.

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.

scholarly journals Fire Resistance of High-Volume Fly Ash RC Slab Inclusion with Nano-Silica

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3311
Author(s):  
Mohamed H. Mussa ◽  
Noor Azim Mohd Radzi ◽  
Roszilah Hamid ◽  
Azrul A. Mutalib
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Fly Ash ◽  
Concrete Slab ◽  
High Volume ◽  
Concrete Cover ◽  
Nano Silica ◽  
Load Curve ◽  
High Volume Fly Ash ◽  
Rc Slab

The study aims to investigate the fire performance of reinforced concrete (RC) slab fabricated from high volume fly ash inclusion with nano-silica (HVFANS) under ISO 834 load curve. The HVFANS concrete slab with dimensions of 1850 mm × 1700 mm × 200 mm was tested via an electrical furnace under an exposing temperature of 1100 °C for 120 min. The slab behaviour was evaluated in terms of residual compressive strength, temperature distribution along its thickness, spalling, and cracks. The results revealed that the slab was capable of maintaining 62.19% of its original compressive strength at room temperature after exposure to the above temperature. Moreover, the distribution of temperature revealed that the temperature of concrete cover and bottom reinforcement was less than 300 °C with a maximum spalling depth of 11 mm within the temperature range of 680 to 840 °C. Furthermore, the thermal conductivity index (K) of the HVFANS concrete was determined, and results indicated that thermal conductivity equalled 0.35 W/mK which is considered low, as compared with other concretes tested in current and previous studies.

Effects of Compressive Strength and Carbonation of HCSA Amount on High Volume Fly Ash Concrete

2011 ◽  
Vol 261-263 ◽  
pp. 333-337
Author(s):  
Juan Hong Liu ◽  
Fang Fang Hou ◽  
Shao Min Song ◽  
Bo Ya Jia
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Internal Structure ◽  
High Volume ◽  
Carbonation Depth ◽  
Fly Ash Concrete ◽  
Resistance Increase ◽  
Expansive Concrete ◽  
High Volume Fly Ash ◽  
Carbonation Resistance

In this article, the effects of compressive strength and carbonation depth of HCSA mixing amount on high volume fly ash concrete have been investigated. Besides, the effects of compressive strength and carbonation depth of the fly ash amount on HCSA expansive concrete have been also analyzed. The results show that proper HCSA mixing amount can improve the compressive strength and anti-carbonation resistance. On the condition of 55% mixing amount of fly ash and 6% HCSA, the compressive strength for 28 days enhanced 8MPa, the carbonation depth decreased by 0.7mm, at the age of 70, the strength increased by 12MPa and the depth reduced 1.7mm; when the mixing amount of HCSA reaches 10%, the internal structure of concrete would be destroyed; In the case of 6% HCSA amount, the compressive strength and anti-carbonation resistance decreases with the increase of fly ash mixing amount. While comparing to the concrete without HCSA, the compressive strength and anti-carbonation resistance increase obviously.

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