TY - CHAP
T1 - Binder chemistry – Blended systems and intermediate Ca content
AU - Provis, J. L.
AU - Bernal, S.A.
PY - 2013/10/9
Y1 - 2013/10/9
N2 - Following the discussion in the two preceding chapters, which addressed high-calcium and low-calcium alkali-activated binder systems respectively, this chapter will provide a brief discussion of the progress which has been made in the development and characterisation of hybrid binders derived from intermediate-Ca precursors and mixtures of precursors. The need for durable, high-performance, low-CO2 alternative binder systems, along with the good existing understanding of the chemical mechanisms of mechanical strength development and durability of high-calcium and low-calcium alkali-activated materials (AAMs) as outlined in Chaps. 3 and 4, has given motivation for an increasing focus on hybrid systems over the past years. These binders are expected to provide a good synergy between mechanical strength and durability, making use of the stable coexistence of the hydration-reaction products characteristic of hydration of Portland clinker or alkali-activated BFS (mainly C-S-H gels) and alkali-activated aluminosilicates (geopolymeric gel) [1–3]. Blending of aluminosilicate-rich materials with more reactive calcium sources (including Portland cement clinker) and with the use of a source of alkalis also opens the possibility for the use of aluminosilicate wastes or by-products which may be insufficiently reactive to provide good strength development when activated alone, providing a pathway to valorisation for these materials.
AB - Following the discussion in the two preceding chapters, which addressed high-calcium and low-calcium alkali-activated binder systems respectively, this chapter will provide a brief discussion of the progress which has been made in the development and characterisation of hybrid binders derived from intermediate-Ca precursors and mixtures of precursors. The need for durable, high-performance, low-CO2 alternative binder systems, along with the good existing understanding of the chemical mechanisms of mechanical strength development and durability of high-calcium and low-calcium alkali-activated materials (AAMs) as outlined in Chaps. 3 and 4, has given motivation for an increasing focus on hybrid systems over the past years. These binders are expected to provide a good synergy between mechanical strength and durability, making use of the stable coexistence of the hydration-reaction products characteristic of hydration of Portland clinker or alkali-activated BFS (mainly C-S-H gels) and alkali-activated aluminosilicates (geopolymeric gel) [1–3]. Blending of aluminosilicate-rich materials with more reactive calcium sources (including Portland cement clinker) and with the use of a source of alkalis also opens the possibility for the use of aluminosilicate wastes or by-products which may be insufficiently reactive to provide good strength development when activated alone, providing a pathway to valorisation for these materials.
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84979937594&partnerID=MN8TOARS
U2 - 10.1007/978-94-007-7672-2_5
DO - 10.1007/978-94-007-7672-2_5
M3 - Chapter or section
SN - 9789400776715
T3 - RILEM State-of-the-Art Reports
SP - 125
EP - 144
BT - Alkali Activated Materials
A2 - Provis, J.
A2 - van Deventer, J.
PB - Springer
CY - Dordrecht, Germany
ER -