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Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Title: Geopolymeric And Cementitious Mortars With The Same Mechanical Strength Class: Performances And Corrosion Behaviour Of Black And Galvanized Steel Bars
Author(s): Alessandra Mobili; Chiara Giosuè; Alberto Belli; Tiziano Bellezze and Francesca Tittarelli
Publication: Special Publication
Appears on pages(s): 18.1-18.10
Keywords: cement, durability, fly ash, geopolymer, mechanical strength, metakaolin, mortar
Abstract:In the prospect of reducing CO2 emissions and landfilling of waste materials, the preparation of sustainable mortars by alkali activation was studied. According to EN 1504-3:2005, geopolymeric and cementitious mortars belonging to different strength classes (R1 ≥ 10 MPa (1450 psi), R2 ≥ 15 MPa (2175 psi) and R3 ≥ 25 MPa (3625 psi)) were tested and compared. Geopolymers were obtained with fly ash or metakaolin and a blend of sodium silicate and NaOH (or KOH). Mortars were tested in terms of workability, dynamic modulus of elasticity, drying and restrained shrinkage and porosimetry. Durability was also investigated in terms of water vapour permeability, capillary water absorption and corrosion of possible embedded rebars during the curing period and wet-dry cycles in 3.5% NaCl solution. Results showed that geopolymers are subjected to higher drying shrinkage but lower restrained shrinkage than cementitious mortars. Water vapour permeability was higher in geopolymers and capillary water absorption was lower especially in fly ash geopolymers than those of cementitious mortars. During the first month, the high alkalinity of geopolymers extends the active state of both black and galvanized steel bars. However, when exposed to chlorides, fly ash geopolymers offer a higher protection to reinforcements than cementitious mortars.
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