Nanosilica Coated Aggregates: Effects on Strength, Microstructure, and Transport Properties of Hydraulic Cement Mortars

Author(s): Parth Panchmatia, Jan Olek, Ehsan Ghafari, Seyedali Ghahari and Lu Na
Paper category: Proceedings
Book title: Proceedings of International Conferences (ICACMS) Advances in Construction Materials and systems Vol 2
Editor(s): Manu Santhanam, Ravindra Gettu, Radhakrishna G. Pillai, Sunitha K. Nayar
ISBN: 978-2-35158-194-0
e-ISBN: 978-2-35158-191-9
Publisher: RILEM Publications SARL
Publication year: 2017
Pages: 98-107
Total Pages: 10
Language : English

Abstract: The typical interface between aggregates and cement paste in unmodified concrete systems, referred to as the interfacial transition zone (ITZ), will often be more porous than the bulk paste and thus is believed to reduce the overall mechanical and durability properties of concrete. Techniques suggested to improve the ITZ often involve the use of pozzolanic cementitious materials to replace a portion of OPC in the bulk mixture. This work discusses targeted application of nano-silica thin films on aggregate surfaces to improve the ITZ and to evaluate the impact of this treatment on the development of mechanical, microstructural, transport, and mineralogical properties of mortar specimens. Preliminary testing has demonstrated that 28-day old mortar samples made with aggregate coated with 25 % (by weight) of colloidal nano-silica solution showed a 50 % increase in compressive strength and approximately three times lower Ca(OH)2 content compared to mortars without nano-silica
treatment. The ITZ of mortar made with nano-silica coated aggregate appeared denser than the ITZ of mortar prepared using virgin aggregate when observed using a SEM. The non-steady state chloride diffusion coefficient of mortar specimen made with nano-silica coated aggregates was approximately one order of magnitude lower than that of the reference mortar specimen.

Online publication : 2017
Publication type : full_text
Public price (Euros) : 0.00