Scaling resistance by fluoro-treatments: The importance of wetting states

Membrane distillation is a thermally driven separation process using hydrophobic, porous membranes. Among various problems faced by membrane distillation, scaling remains an unresolved challenge in treating streams of high salinity....

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

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.

Untitled ItemProperties of Concrete Containing Recycled Concrete Aggregate of Preserved Quality

<p>This study focuses on evaluating recycled concrete aggregate (RCA) of high quality produced through a protocol that preserves the original properties of the concrete to be recycled. Concrete with RCA of preserved quality was compared to concrete with commercially available RCA. A total of 29 mixes were tested with RCA replacement ranging from 30% to 100% of the coarse aggregate. Results showed that concrete with RCA of preserved quality performed significantly better in compressive strength, drying shrinkage, and salt scaling resistance. Furthermore, the use of 30% RCA with preserved quality produced concrete of comparable quality to that of concrete with natural aggregate.</p>

Properties of Concrete Containing Recycled Concrete Aggregate of Preserved Quality

<p>This study focuses on evaluating recycled concrete aggregate (RCA) of high quality produced through a protocol that preserves the original properties of the concrete to be recycled. Concrete with RCA of preserved quality was compared to concrete with commercially available RCA. A total of 29 mixes were tested with RCA replacement ranging from 30% to 100% of the coarse aggregate. Results showed that concrete with RCA of preserved quality performed significantly better in compressive strength, drying shrinkage, and salt scaling resistance. Furthermore, the use of 30% RCA with preserved quality produced concrete of comparable quality to that of concrete with natural aggregate.</p>

Properties of Concrete Containing Recycled Concrete Aggregate of Preserved Quality

<p>This study focuses on evaluating recycled concrete aggregate (RCA) of high quality produced through a protocol that preserves the original properties of the concrete to be recycled. Concrete with RCA of preserved quality was compared to concrete with commercially available RCA. A total of 29 mixes were tested with RCA replacement ranging from 30% to 100% of the coarse aggregate. Results showed that concrete with RCA of preserved quality performed significantly better in compressive strength, drying shrinkage, and salt scaling resistance. Furthermore, the use of 30% RCA with preserved quality produced concrete of comparable quality to that of concrete with natural aggregate.</p>

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

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.