Structural performance of alkali-activated soil ash versus soil cement

• Type: Article in International Scientific Journal
• Date: 2016

Authors

Sara Rios (Author) FEUP; Nuno Cristelo (Author) Other; António Viana da Fonseca (Author) FEUP; Cristiana Ferreira (Author) FEUP

Journal

Title: Journal of Materials in Civil Engineering

Vol. 28 No. 2

ISSN: 0899-1561

Publisher: ASCE

Indexing

ISI Web of Knowledge - 75 Citations

ISI Web of Science

Scopus - 87 Citations

INSPEC

Scientific classification

CORDIS: Technological sciences > Engineering > Civil engineering > Geotechnics

FOS: Engineering and technology > Civil engineering

Other information

Authenticus ID: P-00K-3GK

DOI: 10.1061/(ASCE)MT.1943-5533.0001398

Abstract (EN): Alkaline activation of fly ash (FA) was used to improve the mechanical performance of a silty sand, considering this new material as a replacement for soil-cement applications, namely, bases and subbases, for transportation infrastructures. For that purpose, specimens were molded from mixtures of soil, FA, and an alkaline activator made from sodium hydroxide and sodium silicate. Uniaxial compression tests showed that strength is highly increased by the addition of this new binder. The results described a high stiffness material, with an initial volume reduction followed by significant dilation. All specimens have clearly reached the respective yield surface during shearing, and peakstrength Mohr–Coulomb parameters were defined for each mixture. The evolution of the microstructure during curing, responsible for the mechanical behavior detected in the previous tests, was observed by scanning electron microscopy. These results were compared with soil-cement data obtained previously with the same soil at similar compaction conditions. The main difference between both binders was the curing rate, with alkali-activated specimens showing a more progressive and long-lasting strength increase. This was analyzed taking into account the chemical process responsible for the behavior of the mixtures.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11