scholarly journals Surface Scaling Resistance of Concrete with Fly Ash From Co-Combustion of Coal and Biomass

2013 ◽  
Vol 57 ◽  
pp. 605-613 ◽  
Author(s):  
Marta Kosior-Kazberuk
Keyword(s):  
Fly Ash ◽  
Surface Scaling ◽  
Scaling Resistance

scholarly journals Freeze-Thaw Resistance of Normal and High Strength Concretes Produced with Fly Ash and Silica Fume

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Cenk Karakurt ◽  
Yıldırım Bayazıt
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
High Strength ◽  
Unit Surface Area ◽  
Normal Strength Concrete ◽  
Freeze Thaw ◽  
Strength Concrete ◽  
Thaw Cycle ◽  
Surface Scaling ◽  
Normal Strength

This study is based on determination of the freeze-thaw resistance of air-entrained and non-air-entrained normal strength concrete (NC) and high strength concrete (HSC) produced with fly ash and silica fume according to surface scaling. The procedure allows us to measure the amount of scaling per unit surface area due to a number of well defined freezing and thawing cycles in the presence of deicing salt. The weight loss, surface scaling, moisture uptake, and internal damage were measured after 0 and after every 4th freeze-thaw cycle. The test results showed that the freeze-thaw resistance is influenced directly by the compressive strength property of the concrete. Silica fume significantly reduced the resistance of normal strength concrete against freeze-thaw effect without plasticizing agent. The surface scaling of silica fume concrete without admixture was 22% higher than reference normal concrete.

A study of fly ash concrete in curb and gutter construction under various laboratory and field curing regimes

1987 ◽  
Vol 14 (5) ◽  
pp. 614-620 ◽  
Author(s):  
P. M. Gifford ◽  
B. W. Langan ◽  
R. L. Day ◽  
R. C. Joshi ◽  
M. A. Ward
Keyword(s):  
Fly Ash ◽  
Field Tests ◽  
Moisture Loss ◽  
Strength Development ◽  
Freezing And Thawing ◽  
Fly Ash Concrete ◽  
Dry Out ◽  
Air Void ◽  
Curing Regimes ◽  
Scaling Resistance

It has been assumed that cement – fly ash systems only work efficiently given full curing; low temperatures and (or) moisture loss may lead to poor (slow) strenght development and concomitant reduced freezing and thawing cycling and scaling performance.The aim of the present study, undertaken by the Calgary Fly Ash Research Group, was to examine the validity of the above assumption. Strength development and freezing and thawing durability characteristics of fly ash concretes subjected to a range of environmental variables are reported; laboratory and field tests were performed. The field study involved a coring and laboratory testing programme on three ready-mixed concretes, which were used to machine place 200 m of standard curb and gutter on a major roadway. In the laboratory programme the field concretes and an additional high fly ash mixture were cast; specimens were demoulded at the age of 4 h and were either sealed at the time of casting or allowed to dry out while curing at room temperature or at 5 °C. Strength development, freezing and thawing effects, and scaling resistance as well as air-void parameters were determined; a comparison between the field and laboratory tests is presented. Also reported are measurements of internal concrete temperature and moisture loss versus time for the different curing regimes of the laboratory specimens. Key words: concrete, fly ash, strength, durability, field trial.

scholarly journals Effects of Curing Method on Properties and Salt-Scaling Resistance of Concrete under Lab Testing

2021 ◽  
Author(s):  
Greg Richards ◽  
Medhat Shehata
Keyword(s):  
Fly Ash ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Alkali Concentration ◽  
Salt Scaling ◽  
High Calcium ◽  
Curing Methods ◽  
Curing Method ◽  
High Alkali ◽  
Scaling Resistance

This paper presents a study of the effect of curing on the salt-scaling resistance of concrete containing supplementary cementitious materials (SCMs) under lab conditions. Two curing methods were examined: moist curing and wrapping in a tight plastic sheet. Wrapping concrete slabs in plastic was adopted to represent curing methods that do not supply the concrete with additional water. The two curing methods produced different scaling results; however, the outcomes did not change in terms of meeting or failing the acceptance limit. Curing in plastic wraps produced higher carbonation depth prior to exposing the sample to the salt solution. This could have contributed, partly, to the higher scaling obtained in wrapped samples, other than the sample with 40% high-calcium fly ash. For this sample, there is evidence that curing using plastic wraps maintained high alkali concentration in the surface concrete, which could have enhanced the pozzolanic activity of the fly ash at the surface.

Deicing salt scaling resistance of concrete incorporating fly ash and (or) silica fume: laboratory and field sidewalk test data

2011 ◽  
Vol 38 (4) ◽  
pp. 373-382 ◽  
Author(s):  
N. Bouzoubaâ ◽  
A. Bilodeau ◽  
B. Fournier ◽  
R.D. Hooton ◽  
R. Gagné ◽  
...  
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Blended Cement ◽  
Field Evaluation ◽  
Concrete Mixture ◽  
Test Procedures ◽  
Deicing Salt ◽  
Salt Scaling ◽  
Curing Compound ◽  
Scaling Resistance

Sidewalk sections were cast in fall 2002 with three concrete mixtures that consisted of a control concrete, a concrete mixture incorporating 25% fly ash, and a concrete mixture made with a ternary blended cement (fly ash and silica fume). The curing practices consisted of using curing compound and wet burlap. For each of the sidewalk sections, laboratory specimens were cast on site using the concrete from the same batch. Large slabs (1.2 m × 0.9 m) were also cast from which specimens could be cored and tested in the laboratory for compressive strength and deicing salt scaling resistance following the ASTM and the BNQ test procedures. The results were compared to the performance of the sidewalk sections after six winters of outdoor exposure. A similar study was completed on sidewalk sections cast in spring 2002; the objective of the present study being to confirm the results of the previous investigation, and to determine the effect of the time of casting on the scaling resistance of the concrete i.e., performance of sidewalks cast in spring versus that of sidewalks cast in fall. The field evaluation showed that all the concretes cast in fall scaled relatively more than those placed in spring. Both laboratory results and field evaluations have shown that the use of a curing compound increases the scaling resistance of all the concretes investigated. The results also confirmed the adequateness of the BNQ procedure to better evaluate the deicing salt scaling resistance of concrete made with supplementary cementing materials; however, monitoring the sidewalk sections for a longer period of time is still required to confirm the above observations.

Analysis of the representativeness and relative severity of ASTM C672 and NQ 2621-900 standard procedures in evaluating concrete scaling resistance

2010 ◽  
Vol 37 (11) ◽  
pp. 1471-1482 ◽  
Author(s):  
Ernesto Houehanou ◽  
Richard Gagné ◽  
Marc Jolin
Keyword(s):  
Fly Ash ◽  
Service Life ◽  
Standard Test ◽  
Test Procedures ◽  
Freeze Thaw ◽  
Standard Procedures ◽  
Pretreatment Period ◽  
Realistic Assessment ◽  
Scaling Resistance ◽  
Key Parameter

The aim of this study is to gain an understanding of the representativeness and relative severity of ASTM C672 and NQ 2621-900 standard test procedures in evaluating the scaling resistance of concrete incorporating various proportions of fly ash (25% and 35%), slag (25% and 35%), and silica fume (1% and 2%). Length of curing and presaturation of samples were varied before starting the freeze–thaw tests. Laboratory durability of tested concrete was compared with that of similar concrete after 4 years of service life. Results show that the length of the moist pretreatment period is a key parameter in scaling resistance of laboratory-tested concrete. A 28-day period of moist curing appears to be optimal and leads to more realistic assessment of the actual scaling resistance of concrete. The use of a draining-bottom mold had no significant effect on the scaling resistance of the concretes in this study.

scholarly journals SURFACE SCALING RESISTANCE OF CONCRETE MODIFIED WITH BITUMINOUS ADDITION

2004 ◽  
Vol 10 (1) ◽  
pp. 25-30
Author(s):  
Marta Kosior-Kazberuk ◽  
Walery Jezierski
Keyword(s):  
Construction Industry ◽  
Portland Cement Concrete ◽  
Nacl Solution ◽  
Cement Concrete ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Cold Environments ◽  
Surface Scaling ◽  
Air Entrained Concrete ◽  
Scaling Resistance

Deterioration of concrete due to surface scaling is a very serious durability problem faced by the construction industry in cold environments. The experimental results of resistance to scaling due to cyclic freezing and thawing in the presence of 3 % NaCl solution (de‐icing agent) of not air‐entrained concrete with and without bituminous addition are presented and discussed in the paper. The results have been analysed using the analysis of variance and regression to verify the effect of addition content, number of freeze‐thaw cycles and the sort of cement on concrete ability to scaling. The statistical analysis showed that the bituminous addition significantly improves the scaling resistance of Portland cement concrete.

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