Substitution of Bentonite Aggregates for Pumice in Lightweight Concretes
Bentonite aggregates were pelletized in different grain sizes and the green pellets were then dried for 48 hours and fired in a rotary kiln for one hour at 1150°C with a heating rate of 20 K/min. During firing, the organic compounds in the clay burn off, forcing the pellets to expand and become honeycombed as the outside surface of each granule melts and is sintered. The resulting pellets were lightweight, porous and had high crush resistance. We examined the possibility of using bentonite in different grain sizes as a replacement for pumice in lightweight concretes. Both pumice and bentonitic materials were investigated for their chemical and mineralogical composition (using XRF, XRD, SEM and EDX). Their physico-mechanical properties in concrete pastes, including compressive strength, were evaluated. Phase composition was also determined by XRD, SEM and EDX. The compressive strength and particle and bulk density results showed that these lightweight concretes were affected by the type, shape and percentage of aggregates, the cement paste characteristics, and the interfacial zone between the cement and aggregates. Calcium silicate-hydrate (CSH) and calcium aluminate-hydrate (CAH) minerals were responsible for the strength of the concrete.
Keywordsbentonite clay minerals pumice aggregates lightweight concrete interfacial zone mechanical properties
Unable to display preview. Download preview PDF.
- Ismail A.I.M., Darwish H.: Engineering behaviour of waste glass as aggregates in concrete containing sand and gravels. Interceram 63 (2014) [1–2] 45–48Google Scholar
- Ismail, A.I.M., Mekky, H.S., Elmaghraby, M.S: Assessment and utilization of some Egyptian clay deposits for producing lightweight concrete. Int. J. Mater. Sci. and Appl. 3 (2014)  79–83Google Scholar
- Ismail A.I.M., Elmaghraby M. S: Effect of Limestone Composition and Microstructure on the Strength of Aggregates and Concretes. Interceram 64 (2015) [1–2] 28–32Google Scholar
- Ismail, A.I.M, Souaya, E.R., Abd El-Hakeem, A.: Assessment of different shapes and grain sizes of bentonite aggregates in lightweight concretes. Interceram 65 (2016)  96–99Google Scholar
- Mehta, P.K., Monteiro, P.J.M.: Concrete: microstructure, properties and materials. 3rd ed., Vol. 21, McGraw-Hill, New York (2006) 659 ISBN: 0-07-158919-8, DOI: 10.1036/0071462899Google Scholar
- Kristiawan, S.A., Sangadji, S.: Prediction model for shrinkage of lightweight aggregate concrete. Asian J. Civil. Eng. Build. Hous. 5 (2009)  549–558Google Scholar
- Khaloo, A.R., Ahmad, S.H., El-Dash, K.M.: Behavior of confined high-strength lightweight concrete columns. Asian J. Civil. Eng. Build. Hous. 1 (2000)  13–35Google Scholar
- Khaloo, A.R., Sharifian, M.: Experimental investigation of low to high-strength steel fiber reinforced lightweight concrete under pure torsion. Asian J. Civil. Eng. Build. Hous. 6 (2005)  533–547Google Scholar
- Tuthill, L.H.: Concrete operations in the concrete ship program. ACI J. Proc. 3 (1945)  137–180Google Scholar
- Kluge, R.W., Sparks, M.M., Tuma, E.C.: Lightweight-aggregate concrete. ACI J. Proc. 9 (1949)  625–644Google Scholar
- Jensen, O.M., Lura, P.: Techniques for internal water curing of concrete. Advances in cement and concrete IX, volume changes, cracking and durability. Proceedings of an International Conference, Copper Mountain, CO. (2003) 67–78Google Scholar
- Kumar, S.: Utilisation of FaL-G bricks and blocks in buildings. Ind. Concrete J. 75 (2001)  463–467Google Scholar