Location
Leeds, UK
Event Website
http://docs.lib.purdue.edu/icdcs
Keywords
Compressive strength, Fly ash, Self-compacting concrete, Sulfate attack, XRD.
Abstract
The high-volume fly ash concrete, HVFAC, could be defined as any concrete mix having fly ash content larger than 50 percent of the total cementitious materials content. Due to the availability of fly ash in large quantities globally with low cost, HVFAC could be considered as a solution for the environmental impact of Portland cements. In this study the durability of two high-volume fly ash self-compacting concrete, HVFASCC, mixes exposed to the effects of two sulfate aggressive solutions was investigated. The fly ash, class F, contents for these mixes were 50 and 60 percent by weight of Portland cement. The external sulfate attack was simulated by submerging the concrete specimens in 5 percent sodium and magnesium sulfate solutions separately for 240 days. Six mixes were produced for this purpose, they were: 2 reference mixes cured in water, 2 mixes submerged in Na2SO4 solution and 2 mixes submerged in MgSO4 solution. The testing program includes: slump flow, V-funnel, L-box, weight change, XRD and the strength tests: compressive, splitting and flexural strengths. The fly ash content has a positive effect on the rheology (workability) of all tested mixtures. In other words, increasing the cement replacement level from 50 to 60 percent has enhanced the filling ability, passing ability, and segregation resistance of the investigated SCC mixes. The test results show that the magnesium solution has the higher harmful effect on all mixes than the sodium solution. The replacements of Portland cement by the assigned percentages of fly ash have significantly increased the resistance of SCC to the external sulfate attack due to lime consuming reaction.
Included in
Performance of High-volume Fly Ash Self-compacting Concrete Exposed to External Sulfate Attack
Leeds, UK
The high-volume fly ash concrete, HVFAC, could be defined as any concrete mix having fly ash content larger than 50 percent of the total cementitious materials content. Due to the availability of fly ash in large quantities globally with low cost, HVFAC could be considered as a solution for the environmental impact of Portland cements. In this study the durability of two high-volume fly ash self-compacting concrete, HVFASCC, mixes exposed to the effects of two sulfate aggressive solutions was investigated. The fly ash, class F, contents for these mixes were 50 and 60 percent by weight of Portland cement. The external sulfate attack was simulated by submerging the concrete specimens in 5 percent sodium and magnesium sulfate solutions separately for 240 days. Six mixes were produced for this purpose, they were: 2 reference mixes cured in water, 2 mixes submerged in Na2SO4 solution and 2 mixes submerged in MgSO4 solution. The testing program includes: slump flow, V-funnel, L-box, weight change, XRD and the strength tests: compressive, splitting and flexural strengths. The fly ash content has a positive effect on the rheology (workability) of all tested mixtures. In other words, increasing the cement replacement level from 50 to 60 percent has enhanced the filling ability, passing ability, and segregation resistance of the investigated SCC mixes. The test results show that the magnesium solution has the higher harmful effect on all mixes than the sodium solution. The replacements of Portland cement by the assigned percentages of fly ash have significantly increased the resistance of SCC to the external sulfate attack due to lime consuming reaction.
https://docs.lib.purdue.edu/icdcs/2018/pse/24
