The Effect of Silica Fume and Water/Cement Ratio on the Hydraulic Conductivity of Cement-Based Grout

1990 ◽  
Vol 212 ◽  
Author(s):  
A. A. Al-Manaseer ◽  
M. Onofrei ◽  
M. N. Gray ◽  
B. Shenton
Keyword(s):  
Hydraulic Conductivity ◽  
Silica Fume ◽  
High Performance ◽  
Fractured Rock ◽  
Laboratory Data ◽  
Field Work ◽  
Cementitious Materials ◽  
In Situ Experiments ◽  
Underground Research Laboratory ◽  
Nuclear Fuel Waste

ABSTRACTIn situ experiments at Atomic Energy of Canada Limited’s Underground Research Laboratory have demonstrated that a specially developed high-performance cement-based grout, called the reference grout, consisting of 90% sulphate-resistant cement (Canadian Type 50), 10% silica fume (SF) and superplasticizer can seal very fine fissures in granitic rock. Studies are now in progress to determine the longevity of these materials. This paper describes progress in studies of the hydraulic conductivity (i.e. coefficient of permeability), K, of the grout at water/cementitious materials ratios, w/c, between 0.4 and 0.8. The K was assessed with the grouts under compressive and tensile stress using specially designed radial flow permeameters. The results confirm that the K of the reference grout is two to three orders of magnitude lower than that typically observed for intact granite rock (10−12 m/s). Moreover, the data show that adding silica fume and reducing the w/c decreases K. The hydraulic conductivity data coupled with field work and other laboratory data strongly suggest that the reference grout can be successfully used to seal finely fractured rock in the vicinity of a nuclear fuel waste disposal vault.

scholarly journals The Compressive Strength of High-Performance Concrete and Ultrahigh-Performance

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
E. H. Kadri ◽  
S. Aggoun ◽  
S. Kenai ◽  
A. Kaci
Keyword(s):  
Experimental Data ◽  
Compressive Strength ◽  
Silica Fume ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Strength Gain ◽  
Proposed Model ◽  
Partial Cement Replacement ◽  
Better Than

The compressive strength of silica fume concretes was investigated at low water-cementitious materials ratios with a naphthalene sulphonate superplasticizer. The results show that partial cement replacement up to 20% produce, higher compressive strengths than control concretes, nevertheless the strength gain is less than 15%. In this paper we propose a model to evaluate the compressive strength of silica fume concrete at any time. The model is related to the water-cementitious materials and silica-cement ratios. Taking into account the author's and other researchers’ experimental data, the accuracy of the proposed model is better than 5%.

scholarly journals Production of Ultra-High-Performance Concrete with Low Energy Consumption and Carbon Footprint Using Supplementary Cementitious Materials Instead of Silica Fume: A Review

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8291
Author(s):  
Mays A. Hamad ◽  
Mohammed Nasr ◽  
Ali Shubbar ◽  
Zainab Al-Khafaji ◽  
Zainab Al Masoodi ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Silica Fume ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Ultra High Performance Concrete ◽  
Cement Production ◽  
Granulated Blast Furnace Slag ◽  
The Impact

The increase in cement production as a result of growing demand in the construction sector means an increase in energy consumption and CO2 emissions. These emissions are estimated at 7% of the global production of CO2. Ultra-high-performance concrete (UHPC) has excellent mechanical and durability characteristics. Nevertheless, it is costly and affects the environment due to its high amount of cement, which may reach 800–1000 kg/m3. In order to reduce the cement content, silica fume (SF) was utilized as a partial alternative to cement in the production of UHPC. Nevertheless, SF is very expensive. Therefore, the researchers investigated the use of supplementary cementitious materials cheaper than SF. Very limited review investigates addressed the impact of such materials on different properties of UHPC in comparison to that of SF. Thus, this study aims to summarize the effectiveness of using some common supplementary cementitious materials, including fly ashes (FA), ground granulated blast furnace slag (GGBS), metakaolin (MK) and rice husk ashes (RHA) in the manufacturing of UHPC, and comparing the performance of each material with that of SF. The comparison among these substances was also discussed. It has been found that RHA is considered a successful alternative to SF to produce UHPC with similar or even higher properties than SF. Moreover, FA, GGBS and MK can be utilized in combination with SF (as a partial substitute of SF) as a result of having less pozzolanic activity than SF.

scholarly journals The effect of Vietnam’s nano-silica on mechanical properties of high-performance concrete

2021 ◽  
Vol 72 (1) ◽  
pp. 76-83
Author(s):  
Lam Le Hong ◽  
Lam Dao Duy ◽  
Huu Pham Duy
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Nano Silica ◽  
Nano Sio2 ◽  
Curing Period ◽  
Compressive Strength Test

The demand for High Performance Concrete (HPC) is steadily increasing with massive developments. Conventionally, it is possible to use industrial products such as silica fume (SF), fly ash, as supplementary cementitious materials (SCM), to enhance the attributes of HPC. In recent years, nano-silica (NS) is used as an additive in added mainly to fill up the deviation arises with the addition of SF for HPC. This study aims to optimize the proportion of NS (produced in Vietnam) in the mixture used for fabricating 70 MPa high-performance concrete. SiO2 powder with particle size from 10 to 15 nm were used for mixing. A series of compressive strength test of HPC with nano-SiO2 varied from 0 to 2.8 percent of total of all binders (0%, 1.2%, 2%, 2.8%), and the fixed percentage of silica fume at 8% were proposed. Results show compressive strength increases with the increase of nano-SiO2, but this increase stops after reaching 2%. And at day 28 of the curing period, only concrete mixture containing of 8% silica fume and 2% nano-SiO2, had the highest compressive strength.

scholarly journals Improving Environmental Efficiency of Reverse Filling Cementitious Materials through Packing Optimization and Fiber Incorporation

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 647
Author(s):  
Yang Liu ◽  
Lou Chen ◽  
Keren Zheng ◽  
Qiang Yuan
Keyword(s):  
Mechanical Property ◽  
Silica Fume ◽  
Packing Density ◽  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Environmental Efficiency ◽  
Fiber Reinforced Concrete ◽  
Filling System

To improve the environmental efficiency of the reverse filling system, three strategies aim to optimize the packing density, and the mechanical property were adopted in this study. Based on the compressive packing model (CPM), the relationship between the D50 ratio and maximum theoretical packing density for a reverse filling system with 25% and 30% superfine Portland cement was established. For comparison, silica fume and steel fiber were also added to the reverse filling system, respectively. The improvement of packing density by adjusting the D50 ratio was verified through the minimum water demand method, CPM, and modified Andreasen and Andersen (MAA) model. Compared to the reverse filling system added with 3 wt % silica fume, which possesses a comparable mechanical property with the optimized group (adjusted D50 ratio), the incorporation of steel fiber shows a more significant increase. The environmental efficiency of all the samples was quantified into five aspects through the calculation based on the mix proportion, compressive strength, and hydration degree. The comprehensive evaluation demonstrated that the optimized reverse filling system exerts a lower environmental impact and possesses a much higher cement use efficiency compared to the majority of ultra-high performance concrete (UHPC)/ ultra-high performance fiber-reinforced concrete (UHPFRC) reported in published papers.

scholarly journals Effect of FC3R on the properties of ultra-high-performance concrete with recycled glass

DYNA ◽  
2019 ◽  
Vol 86 (211) ◽  
pp. 84-93 ◽  
Author(s):  
Nancy Torres Castellanos ◽  
Jaime Antonio Fernández Gómez ◽  
Andres Mauricio Nuñez Lopez
Keyword(s):  
Silica Fume ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Substitution ◽  
Ultra High Performance Concrete ◽  
Conventional Concrete ◽  
Recycled Glass ◽  
Cost Efficient

Ultra-high-performance concrete (UHPC) is the essential innovation in concrete research of the recent decades. However, because of the high contents of cement and silica fume used, the cost and environmental impact of UHPC is considerably higher than conventional concrete. The use of industrial byproducts as supplementary cementitious materials, in the case of recycled glass powder and fluid catalytic cracking catalyst residue (FCC), the partial substitution of cement and silica fume allows to create a more ecological and cost-efficient UHPC. This research presents a study to determine the possibility of partial substitution of cement by FCC in a previously optimized mixture of ultra-high-performance concrete with recycled glass. The results demonstrate that compressive strength values of 150 and 151 MPa without any heat treatment can be achieved, respectively, when replacing 11% and 15% of the cement with FCC, for a determined amount of water and superplasticizer, compared to 158 MPa obtained for the reference UHPC without any FCC content. The rheology of fresh UHPC is highly decreased by replacing cement particles with FCC.

Developments for in Situ Tests on Compacted Bentonite-Based Buffer Material

1990 ◽  
Vol 212 ◽  
Author(s):  
B. H. Kjartanson ◽  
M. N. Gray ◽  
B.C.M. Pulles
Keyword(s):  
Large Scale ◽  
Large Diameter ◽  
Full Scale ◽  
In Situ Tests ◽  
Buffer Material ◽  
In Situ Experiments ◽  
Buffer Mixture ◽  
Underground Research Laboratory ◽  
Nuclear Fuel Waste

ABSTRACTAECL Research is carrying out large-scale in situ experiments at its Underground Research Laboratory (URL). The Buffer/Container Experiment is designed principally to investigate the full scale, in situ performance of bentonite-based buffer material in a single emplacement borehole environment. In addition, the response of the rock to excavation and heating will be investigated. The experiment also allows for the development of the technologies needed to demonstrate some of the vault engineering activities proposed in the Canadian nuclear fuel waste disposal concept. These include excavation of large diameter boreholes for waste emplacement and in situ compaction of a bentonite/sand buffer mixture. Although these methodologies developed for the URL have not been optimized for the commercial, full-scale operations needed for a disposal vault, results show that the equipment and methodologies needed for vault operations are a reasonable extrapolation of existing technology.

The Development of Durable Cementitious Materials for Use in a Nuclear Fuel Waste Disposal Facility

1985 ◽  
Vol 50 ◽  
Author(s):  
N. C. Burnett ◽  
R. D. Hooton ◽  
R. B. Heimann ◽  
M. Onofrei
Keyword(s):  
Silica Fume ◽  
Saline Solution ◽  
Cementitious Materials ◽  
Canadian Shield ◽  
Potassium Ions ◽  
Leaching Tests ◽  
Short Term ◽  
Supplementary Cementing Materials ◽  
Disposal Facility ◽  
Nuclear Fuel Waste

AbstractThis paper describes the work on cement paste development and short-term leaching tests in Standard Canadian Shield Saline Solution (SCSSS) in the presence of bentonite at 150°C. It has been found that:-supplementary cementing materials such as silica fume or fly ash could significantly improve the properties of sulphate resistant portland cement (SRPC), in particular, permeability to water and pore size distribution.-the addition of bentonite suppressed the normal tendency of the pH of groundwater to increase rapidly in the presence of cement.-the presence of bentonite increased the release of potassium ions from the cements.-– SRPC blended with 20% silica fume resulted in a groundwater pH lower than that of SRPC, with and without bentonite. Moreover, its cumulative fraction of release of potassium was significantly lower than that of SRPC.

Influence of the Type of Silica Fume on the Rheological and Mechanical Properties of Ultra-High Performance Concrete

2011 ◽  
Vol 488-489 ◽  
pp. 274-277 ◽  
Author(s):  
Kyung Taek Koh ◽  
Jung Jun Park ◽  
Su Tae Kang ◽  
Gum Sung Ryu
Keyword(s):  
Mechanical Properties ◽  
Surface Area ◽  
Silica Fume ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Ultra High Performance Concrete ◽  
Coarse Aggregates ◽  
Surface Areas ◽  
Compressive And Flexural Strengths

Ultra-high performance concrete (UHPC) is a new generation of concrete developed through microstructure enhancement techniques for cementitious materials. UHPC exhibits extremely high compressive and flexural strengths exceeding 180 and 30 MPa, respectively, and remarkable durability compared to normal concretes. The fabrication of UHPC requires very low W/B ratio reaching merely 0.2, the use of large quantities of fine binder and superplasticizer without coarse aggregates, and the incorporation of steel micro-fibers. This study investigates the effect of the type of silica fume on the rheological and mechanical properties of UHPC. The adopted silica fume presents various contents of SiO2 and surface areas. From the experimental results, UHPC using silica fume with 94% of SiO2 3% of ZrO2, and surface area of 80,000 g/cm3 shows better flowability than UHPC using silica fume with 98% of SiO2and surface area of 200,000 g/cm3 by lowering the viscosity of the cementitious composites without decreasing the compressive strength. Therefore, the fabrication cost of UHPC can be reduced by smaller dosage of superplasticizer when using silica fume with Zr content .

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