scholarly journals Partial Replacement of Microsilca on Compressive Strength Concrete: Applying Predictive Model

2020 ◽  
Vol 4 (1) ◽  
Keyword(s):  
Silica Fume ◽  
Concrete Strength ◽  
High Surface ◽  
Pozzolanic Reaction ◽  
Influential Factors ◽  
Influential Factor ◽  
Partial Replacement ◽  
Strength Development ◽  
Predictive Values ◽  
Micro Silica

Monitoring the rate of micro-silica variation was carried out to determine different rate of strength developed applying various dosage, these are the pozzolanic reaction which occurs between silica fume and CH producing additional CSH in many of the voids around hydrated cement particles. This is due to high surface area of silica fume that normally affect the mobility of water within concrete segregation, this include bleeding of concrete that are virtually eliminated . This application detailed on the reactions from micro-silica reflection of it are influential factors on rapid increase of concrete strength, these are based on the mixed designed output, such application reflects the significant growth rate of concrete performance in the study, mathematical model application using analytical solution generated derived model for the study, this derived model techniques developed predictive values through simulation, the predictive were applied on the reflection of various water cement ratios including variation of micro-silica dosage numerically to ninety days of curing, water cement ratios influence of strength development were expressed in the study, variation of concrete permeability and void ratios are also detailed as an influential factor in concrete formations, the study has express its significant influence based on the developed strength within seven and ninety days of curing.

The Pozzolanic Reaction of Silica Fume

2012 ◽  
Vol 1488 ◽  
Author(s):  
Ole M. Jensen
Keyword(s):  
Silica Fume ◽  
High Performance ◽  
Cement Hydration ◽  
Theoretical Calculations ◽  
Pozzolanic Reaction ◽  
Interfacial Transition Zone ◽  
Strength Development ◽  
Micro Structure ◽  
Cementitious Binder ◽  
Portland Cement Hydration

ABSTRACTSilica fume is a very important supplementary cementitious binder in High-Performance and Ultra High-Performance Concretes. Through its pozzolanic reaction the silica fume densifies the concrete micro-structure, in particular it strengthens the paste-aggregate interfacial transition zone. In the present paper different aspects of the pozzolanic reaction of silica fume are investigated. These include chemical shrinkage, isothermal heat development and strength development. Key data for these are given and compared with theoretical calculations, and based on presented measurements the energy of activation of the pozzolanic reaction of silica fume is estimated. The results show that the pozzolanic reaction of silica fume has notable differences from Portland cement hydration.

A Strength Model for Concretes Containing Fly Ash, Blast-Furnace Slag and Silica Fume

1985 ◽  
Vol 65 ◽  
Author(s):  
Edwin R. Dunstan
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Silica Fume ◽  
Blast Furnace Slag ◽  
Concrete Strength ◽  
Pozzolanic Reaction ◽  
Strength Data ◽  
Production Mechanisms ◽  
Furnace Slag ◽  
By Products

ABSTRACTThis paper describes preliminary a model for the strength of concretes containing industrial by-products such as fly ash, blast-furnace slag, and silica fume. A formula that describes the various strength production mechanisms of these by-products is developed. These materials produce strength by pozzolanic reaction, by latently hydraulic reactions and by self-cementing reactions similar to Portland cement. A method of separating the effect of each mechanism is proposed. A parameter for each of these strength producing mechanisms can be determined from concrete strength data.

scholarly journals Enhancement of Material Properties of Lime-Activated Slag Mortar from Intensified Pozzolanic Reaction and Pore Filling Effect

2018 ◽  
Vol 10 (11) ◽  
pp. 4290 ◽  
Author(s):  
Yang-Hee Kwon ◽  
Sung-Hoon Kang ◽  
Sung-Gul Hong ◽  
Juhyuk Moon
Keyword(s):  
Silica Fume ◽  
Material Properties ◽  
Pozzolanic Reaction ◽  
Physical Effect ◽  
Strength Development ◽  
Pore Filling ◽  
Improvement Strategy ◽  
Microstructural Investigation ◽  
Curing Condition ◽  
Activated Slag

To utilize alkali-activated materials widely, this study investigates the effects of an intensified pozzolanic reaction and pore filling by silica fume on various material properties of lime-activated slag mortar. Although ground-granulated blast-furnace slag is classified as a cementitious material, it commonly requires an activator to enhance the performance of structural materials. In the first step of the improvement strategy, slag reaction is activated by hydrated lime. Next, silica fume is added to densify the microstructure by the physical pore filling effect and/or the pozzolanic reaction that additionally forms hydration products. This increased the compressive strength by 18% at 28 days and by 25% at 91 days under ambient curing condition, mainly due to the physical effect. Moreover, elevated temperature curing for three days was highly effective to further improve the strength, and to accelerate strength development. This is because both the physical effect and the chemical reaction are effective at the high temperature curing condition. The conducted microstructural investigation provided the evidence for the intensified pozzolanic reaction and pore filling effect, both of which are closely related to the mechanical properties. It is also found that the use of silica fume positively contributes to the dimensional stability. Since the developed material exhibits high strength (>40 MPa after 14 days) without Portland cement or highly toxic chemicals, it can be practically used as an eco-friendly structural mortar.

scholarly journals Effect of Using Micropalm Oil Fuel Ash as Partial Replacement of Cement on the Properties of Cement Mortar

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Kwangwoo Wi ◽  
Han-Seung Lee ◽  
Seungmin Lim ◽  
Mohamed A. Ismail ◽  
Mohd Warid Hussin
Keyword(s):  
Compressive Strength ◽  
Cement Mortar ◽  
Isothermal Calorimetry ◽  
High Surface ◽  
High Surface Area ◽  
Xrd Analysis ◽  
Pozzolanic Reaction ◽  
Partial Replacement ◽  
Fuel Ash ◽  
Oil Fuel

This study investigates the effects of micropalm oil fuel ash (mPOFA) on compressive strength and pore structure of cement mortar. Various experimental techniques, such as compression test, isothermal calorimetry, mercury intrusion porosimetry, and X-ray diffraction, are performed to figure out the effect of using mPOFA as partial replacement of cement on the hydration of cement and determine its optimal replacement level to increase mechanical property of the mortar specimens. 10 wt.% of cement replacement with mPOFA is found to give the highest level of compressive strength, achieving a 23% increase over the control specimens after 3 days of curing. High K2O contents in mPOFA stimulate C3S in cement to form C-S-H at early ages, and high surface area of mPOFA acts as a nucleus to develop C-S-H. Also, small mPOFA particles and C-S-H formed by pozzolanic reaction fill the pores and lead to reduction in large capillary pores. In XRD analysis, a decrease in Ca(OH)2 and SiO2 contents with age confirmed a high pozzolanic reactivity of mPOFA.

scholarly journals Pozzolanic Reaction Mechanism of Rice Husk Ash in Concrete – A Review

2015 ◽  
Vol 773-774 ◽  
pp. 1143-1147 ◽  
Author(s):  
Siti Asmahani Saad ◽  
Mohd Fadhil Nuruddin ◽  
Nasir Shafiq ◽  
Maisarah Ali
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash ◽  
Agricultural Waste ◽  
Concrete Strength ◽  
Short Review ◽  
Pozzolanic Reaction ◽  
Milling Process ◽  
Strength Development ◽  
Pulverized Fuel ◽  
Rice Milling

Recently, incorporation of cement replacement material (CRM) in concrete has gained considerable attention throughout the world. It is known that the commonly used CRM in current concrete industry is silica fume (SF), pulverized fuel ash (PFA) and rice husk ash (RHA). RHA is an agricultural waste from rice milling process. Rice farming activities is one of the main crops planted in Malaysia and therefore, the rice husk abundantly generated every year. RHA exhibits positive pozzolanic reaction during concrete strength development. The material contains amorphous silica and hence it contributed towards enhancement of various concrete properties. This paper presents a short review of RHA properties as CRM and pozzolanic reaction determination.

Effect of micro-silica fume and fly ash as a partial replacement of cement on fresh and early strength properties of concrete

2018 ◽  
Author(s):  
Khalid M. Breesem ◽  
Salim H. Jassam ◽  
Amar A. Hussein ◽  
Omar S. Dahham ◽  
N. Z. Noriman ◽  
...  
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Strength Properties ◽  
Partial Replacement ◽  
Early Strength ◽  
Micro Silica

scholarly journals MODELING AND SIMULATION OF WOOD AND FLY ASH BEHAVIOUR AS PARTIAL REPLACEMENT FOR CEMENT ON FLEXURAL STRENGTH OF SELF COMPACTING CONCRETE

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Eluozo S.N. ◽  
Dimkpa K
Keyword(s):  
Flexural Strength ◽  
Concrete Strength ◽  
Partial Replacement ◽  
Self Compacting Concrete ◽  
Predictive Values ◽  
Experimental Procedure ◽  
Cement Ratio ◽  
Analytical Simulation ◽  
Experimental Values ◽  
Curing Age

Flexural strength was monitor and predicted on the application improving concrete strength with wood and fly as partial replacement for cement. The study observed the pressure from the constituent of these locally sourced material that has been observed from the study to influence the flexural strength through the effect from this locally sourced addictives, the study monitors concrete porosity on heterogeneity as it reflect on the flexural strength of self compacting concrete, other condition considered was the compaction and placement of concrete, these effects were monitored at  constant water cement ratio from design mix, the behaviour from this effects on the concrete observed the rate of flexural growth under the influences of these stated conditions, the simulation expressed the reactions of these effects through these parameters monitored to influence the system, numerical simulations were also applied to the optimum curing age of twenty eight days, while analytical simulation was also applied, this concept are the conventional seven days interval that concrete curing were observed, these are improvement done on the study carried out by SachinPrabhu et al 2018, these locally sourced material were experimentally applied, the simulation predictive values is at the interval of seven days of curing, which was also simulated. the predictive values were compared with the experimental values of SachinPrabhu et al 2018, and both values developed best fits correlations, the study is imperative because the system considered  the parameters used on experimental and observed other influential variables that were not examined, these were not observed in the experimental procedure, experts in concrete engineering will definitely find these concept a better option in monitoring flexural strength   of self compacting concrete in general.

scholarly journals Potential Utilization of Micro Silica as a Limited Substitution with Addition of Glass and Polypropylene Fiber for M40 Concrete

2019 ◽  
Vol 8 (12) ◽  
pp. 4961-4967
Keyword(s):  
Silica Fume ◽  
Polypropylene Fiber ◽  
Strength Properties ◽  
Mix Design ◽  
Waste Materials ◽  
Partial Replacement ◽  
Conventional Concrete ◽  
Waste Products ◽  
Concrete Mix Design ◽  
Micro Silica

Nowadays there is an increase in environmental knowledge and its effects on the environment, the disposal of waste products from industries are being big deal to manage. Such waste materials cannot be dumped on any lands, due to this reason it is difficult to manage waste materials. After so many investigations finally conclude that waste material can be utilized in the construction as additives, such materials can reduce the cost of construction and gives more strength compared to conventional concrete. These products can be utilized to partial replacement of cement. In this investigation, we are using Silica fume/ Micro silica as a partial replacement of cement. From this combination, we can improve the strength, workability and resist cracks in concrete. To reduce water content PAR PLAST SPL super plasticizer is used. The present investigation is to determine the strength behavior of Silica fume/Micro silica and fibres in Rigid pavement. The concrete mix design is as per IRC 44 2009, and it is proportioned to set target mean strength as 40 Mpa. The water-cement ratio as per mix design is 0.38. Specimens was casted and cured for various percentages that are 0%, 2.5%, 5%, 7.5% and 10%. With this constant percentage of fibres was added that is 1% Polypropylene fibre and 0.5% Glass fibre. This specimen tested for 3, 7, 28 days for cubes and 7, 28 days for beams and cylinders. From this investigation, Cement can be replaced with Micro silica to improve strength properties like bending and tensile strength. The Silica fume/ micro silica found at 7.5% optimum dosage, up to this percentage cement can be replaced.

An Experimental Study On Concrete Containing Nano And/Or Micro Silica

2021 ◽  
Author(s):  
Sabih Muhodir ◽  
Keyword(s):  
Silica Fume ◽  
Cement Content ◽  
Partial Substitution ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Test Results ◽  
Nano Silica ◽  
Constant Content ◽  
Mechanical And Physical Properties ◽  
Micro Silica

The effect of using Portland cement, nano silica (NS) and /or micro silica on the mechanical and physical properties of concretes containing fine aggregate only is investigated. Two groups divided into five series each have been designed and tested. The first group was containing the nano-silica only, while the second group contained different ratios of nano silica and a constant content of 8 % of silica fume (SF) (by weight) as partial replacement of cement. Water cementations ratio (w/c) of all mixtures was constant and equal to 0.22. The cement content in all series was 800 kg/m3. Commercially available nano silica (NS) was used in the mixture for the partial substitution of cement at ratios of 0, 0.5, 1.0, 2 and 3% by weight. It was found that the addition of nano –silica is significantly enhance compressive, tensile and modulus of elasticity of concrete. From the test results obtained it has been noted that the mix containing 2 % possess significantly improved mechanical properties, furthermore, the group samples of concrete containing binary cementations nano-silica and silica fume showed better results than concrete containing nano silica only.

scholarly journals Heat-Induced Acceleration of Pozzolanic Reaction Under Restrained Conditions and Consequent Structural Modification

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2950
Author(s):  
Nankyoung Lee ◽  
Yeonung Jeong ◽  
Hyunuk Kang ◽  
Juhyuk Moon
Keyword(s):  
High Temperature ◽  
Silica Fume ◽  
High Performance ◽  
Structural Modification ◽  
Cement Hydration ◽  
Mechanical Performance ◽  
High Performance Concrete ◽  
Pozzolanic Reaction ◽  
Strength Development ◽  
Ultra High Performance Concrete

This study investigated the heat-induced acceleration of cement hydration and pozzolanic reaction focusing on mechanical performance and structural modification at the meso- and micro-scale. The pozzolanic reaction was implemented by substituting 20 wt.% of cement with silica fume, considered the typical dosage of silica fume in ultra-high performance concrete. By actively consuming a limited amount of water and outer-formed portlandite on the unreacted cement grains, it was confirmed that high-temperature curing greatly enhances the pozzolanic reaction when compared with cement hydration under the same environment. The rate of strength development from the dual reactions of cement hydration and pozzolanic reaction was increased. After the high-temperature curing, further strength development was negligible because of the limited space availability and preconsumption of water under a low water-to-cement environment. Since the pozzolanic reaction does not directly require the anhydrous cement, the reaction can be more easily accelerated under restrained conditions because it does not heavily rely on the diffusion of the limited amount of water. Therefore, it significantly increases the mean chain length of the C–S–H, the size of C–S–H globules with a higher surface fractal dimension. This finding will be helpful in understanding the complicated hydration mechanism of high-strength concrete or ultra-high performance concrete, which has a very low water-to-cement ratio.

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