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Title: Structure and Properties of Portland-Limestone Cements Synthesized with Biologically Architected Calcium Carbonate
Portland cement is one of the most used materials on earth. Its annual production is responsible for approximately 7% of global carbon dioxide (CO2) emissions. These emissions are primarily associated with (1) the burning of fossil fuels to heat cement kilns and (2) the release of CO2 during limestone calcination. One proposed strategy for CO2 reduction includes the use of functional limestone fillers, which reduce the amount of portland cement in concrete without compromising strength. This study investigated the effect of using renewable, CO2-storing, biogenic CaCO3 produced by E. huxleyi as limestone filler in portland limestone cements (PLCs). Biogenic CaCO3 was used to synthesize PLCs with 0, 5, 15, and 35% limestone replacement of portland cement. The results substantiate that the particle sizes of the biogenic CaCO3 were significantly smaller and the surface areas significantly larger than that of reagent grade CaCO3. X-ray diffraction indicated no differences in mineralogy between reagent-grade and biogenic CaCO3. The use of biogenic CaCO3 as a limestone filler led to (i) increased water demand at the higher replacements, which was countered by using a superplasticizer, and (ii) enhanced nucleation during cement hydration, as measured by isothermal conduction calorimetry. The 7-day compressive strengths of the PLC pastes were measured using mechanical testing. Enhanced nucleation effects were observed for PLC samples containing biogenic CaCO3. 7-day compressive strength of the PLCs produced using biogenic CaCO3 were also enhanced compared to PLCs produced using reagent-grade CaCO3 due to the nucleation effect. This study illustrates an opportunity for using CO2-storing, biogenic CaCO3 to enhance mechanical properties and CO2 storage in PLCs containing biologically architected CaCO3.  more » « less
Award ID(s):
1943554
NSF-PAR ID:
10451925
Author(s) / Creator(s):
; ;
Editor(s):
Amziane, S; Merta, I; Page, J.
Date Published:
Journal Name:
Proceedings of ICBBM 2023: Biobased Building Materials
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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