Engineering Properties of Alkali-Activated Natural Pozzolan Concrete

The development of alkali-activated binders with superior engineering properties and longer durability has emerged as an alternative to ordinary portland cement (OPC). It is possible to use alkali-activated natural pozzolans to prepare environmentally friendly geopolymer cement leading to the concept of sustainable development. This paper presents a summary of an experimental work that was conducted to determine mechanical strength, modulus of elasticity, ultrasonic pulse velocity, and shrinkage of different concrete mixtures prepared with alkali-activated Iranian natural pozzolans—namely Taftan andesite and Shahindej dacite, both with and without calcining. Test data were used for Taftan pozzolan to identify the effects of water-binder ratios (w/b) and curing conditions on the properties of the geopolymer concrete, whereas the influence of material composition was studied by activating Shahindej pozzolan both in the natural and calcined states. The results show that alkali-activated natural pozzolan (AANP) concretes develop moderate-to-high mechanical strength with a high modulus of elasticity and a shrinkage much lower than with OPC.

[1]  B. Vijaya Rangan,et al.  ON THE DEVELOPMENT OF FLY ASH-BASED GEOPOLYMER CONCRETE , 2004 .

[2]  B. Vijaya Rangan,et al.  Low-Calcium fly ash-based geopolymer concrete: Long-term properties , 2006 .

[3]  Francisca Puertas,et al.  MECHANICAL AND DURABLE BEHAVIOUR OF ALKALINE CEMENT MORTARS REINFORCED WITH POLYPROPYLENE FIBRES , 2003 .

[4]  A. Neville.  Properties of Concrete , 1968 .

[5]  T. Cheng,et al.  Fire-resistant geopolymer produced by granulated blast furnace slag , 2003 .

[6]  J. Deventer,et al.  The geopolymerisation of alumino-silicate minerals , 2000 .

[7]  J.S.J. van Deventer,et al.  The potential use of geopolymeric materials to immobilise toxic metals: Part I. Theory and applications☆ , 1997 .

[8]  Ángel Palomo,et al.  Engineering Properties of Alkali-Activated Fly Ash Concrete , 2006 .

[9]  Ángel Palomo,et al.  Alkali-activated fly ashes: A cement for the future , 1999 .

[10]  Brian H. O'Connor,et al.  Chemical optimisation of the compressive strength of aluminosilicate geopolymers synthesised by sodium silicate activation of metakaolinite , 2003 .

[11]  K. MacKenzie,et al.  Synthesis and characterisation of materials based on inorganic polymers of alumina and silica: sodium polysialate polymers , 2000 .

[12]  J.S.J. van Deventer,et al.  THE EFFECT OF COMPOSITION AND TEMPERATURE ON THE PROPERTIES OF FLY ASH- AND KAOLINITE -BASED GEOPOLYMERS , 2002 .

[13]  Hua Xu.  Geopolymerisation of aluminosilicate minerals , 2002 .

[14]  Yao Xiao,et al.  Role of water in the synthesis of calcined kaolin-based geopolymer , 2009 .

[15]  María Teresa Blanco-Varela,et al.  Chemical stability of cementitious materials based on metakaolin , 1999 .

[16]  D. Bondar.  Alkali activation of Iranian natural pozzolans for producing geopolymer cement and concrete , 2009 .