Next Article in Journal
Advances and Applications of Ion Torrent Personal Genome Machine in Cutaneous Squamous Cell Carcinoma Reveal Novel Gene Mutations
Next Article in Special Issue
TiO2-Based Photocatalytic Geopolymers for Nitric Oxide Degradation
Previous Article in Journal
Use of Natural-Fiber Bio-Composites in Construction versus Traditional Solutions: Operational and Embodied Energy Assessment
Previous Article in Special Issue
Some Issues of Shrinkage-Reducing Admixtures Application in Alkali-Activated Slag Systems
Open AccessFeature PaperArticle

Environmentally-Friendly Dense and Porous Geopolymers Using Fly Ash and Rice Husk Ash as Raw Materials

Department of Applied Science and Technology, INSTM Research Unit Polito, Lince Laboratory, Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino 10129, Italy
Author to whom correspondence should be addressed.
Academic Editor: Arie van Riessen
Materials 2016, 9(6), 466;
Received: 15 May 2016 / Revised: 1 June 2016 / Accepted: 8 June 2016 / Published: 14 June 2016
(This article belongs to the Special Issue Advances in Geopolymers and Alkali-Activated Materials)
This paper assesses the feasibility of two industrial wastes, fly ash (FA) and rice husk ash (RHA), as raw materials for the production of geopolymeric pastes. Three typologies of samples were thus produced: (i) halloysite activated with potassium hydroxide and nanosilica, used as the reference sample (HL-S); (ii) halloysite activated with rice husk ash dissolved into KOH solution (HL-R); (iii) FA activated with the alkaline solution realized with the rice husk ash (FA-R). Dense and porous samples were produced and characterized in terms of mechanical properties and environmental impact. The flexural and compressive strength of HL-R reached about 9 and 43 MPa, respectively. On the contrary, the compressive strength of FA-R is significantly lower than the HL-R one, in spite of a comparable flexural strength being reached. However, when porous samples are concerned, FA-R shows comparable or even higher strength than HL-R. Thus, the current results show that RHA is a valuable alternative to silica nanopowder to prepare the activator solution, to be used either with calcined clay and fly ash feedstock materials. Finally, a preliminary evaluation of the global warming potential (GWP) was performed for the three investigated formulations. With the mix containing FA and RHA-based silica solution, a reduction of about 90% of GWP was achieved with respect to the values obtained for the reference formulation. View Full-Text
Keywords: geopolymers; mechanical properties; microstructure; porosity geopolymers; mechanical properties; microstructure; porosity
Show Figures

Figure 1

MDPI and ACS Style

Ziegler, D.; Formia, A.; Tulliani, J.-M.; Palmero, P. Environmentally-Friendly Dense and Porous Geopolymers Using Fly Ash and Rice Husk Ash as Raw Materials. Materials 2016, 9, 466.

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

Back to TopTop