Next Article in Journal
Survey of Network Coding Based P2P File Sharing in Large Scale Networks
Previous Article in Journal
Analysis of Influence of the Welding Procedure on Impact Toughness of Welded Joints of the High-Strength Low-Alloyed Steels
Previous Article in Special Issue
A Critical Review on the Influence of Fine Recycled Aggregates on Technical Performance, Environmental Impact and Cost of Concrete
Open AccessFeature PaperArticle

Effect of Alkali Concentration on the Activation of Carbonate-High Illite Clay

1
Dipartimento di Scienze della Terra e Geoambientali, Università degli Studi di Bari Aldo Moro, 70121 Bari, Italy
2
Instituto Eduardo Torroja (CSIC), 28033 Madrid, Spain
*
Authors to whom correspondence should be addressed.
Appl. Sci. 2020, 10(7), 2203; https://doi.org/10.3390/app10072203 (registering DOI)
Received: 25 February 2020 / Revised: 13 March 2020 / Accepted: 16 March 2020 / Published: 25 March 2020
(This article belongs to the Special Issue Low Binder Concrete and Mortars)
The present study explores the effect of activating solution concentration (4, 6 and 8 M NaOH) on mechanically and thermally pre-treated carbonate-high illite clay (LCR). Pastes were prepared with an alkaline solution/clay (S/B) ratio of 0.55, which were cured at room temperature and relative humidity > 90% in a climatic chamber. At two and 28 days, compressive mechanical strength was determined, and the reaction products were characterised by X-ray Powder Diffraction analysis (XRPD), Fourier-transform infrared spectroscopy (FTIR) and Scanning Electron Microscopy - Energy Dispersive X-ray spectroscopy (SEM/EDX). Results obtained showed that the presence of reactive calcium in the starting clay induces co-precipitation of a mix of gels: An aluminium-enriched C-S-H gel (C-A-S-H) and a N-A-S-H gel, in which sodium is partially replaced by calcium (N,C)-A-S-H. Pastes prepared with higher (6 or 8 M) activator concentrations exhibit a more compact matrix than the ones prepared with 4 M NaOH. The findings show that the use of a 6 M NaOH solution yields a binder with two days compressive strength >20 MPa and 28 days strength of over 30 MPa. View Full-Text
Keywords: carbonate-high illite clay; alkali activation; NaOH; activator concentration carbonate-high illite clay; alkali activation; NaOH; activator concentration
Show Figures

Graphical abstract

MDPI and ACS Style

D’Elia, A.; Pinto, D.; Eramo, G.; Laviano, R.; Palomo, A.; Fernández-Jiménez, A. Effect of Alkali Concentration on the Activation of Carbonate-High Illite Clay. Appl. Sci. 2020, 10, 2203.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop