Page 13 - New Trends in Eco efficient and Recycled Concrete

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13 Application of alkali-activated industrial waste 357
Jordi Paya ´, Francisco Agrela, Julia Rosales, Marı ´ a Martı ´ n Morales
and Marı ´ a Victoria Borrachero
13.1 Alkali-activated cement and concrete 357
13.1.1 Necessity to develop low-carbon cement and concrete 357
13.1.2 Alkali-activated materials (AAMs): a definition 358
13.1.3 Role of precursors and alkaline activators 359
13.1.4 Performance of AAMs cement and concrete:
rheology, mechanical behaviour and durability 360
13.2 New precursors and activators from wastes 361
13.2.1 Precursors based on wastes 362
13.2.2 New alkaline activators 391
13.2.3 Alkaline activators with total replacement
of the synthetic reagent 394
13.3 Reuse of recycled aggregates in alkali-activated mortars
and concrete 397
13.3.1 Composition and content of alkali-activated slag
mortars and concrete (AASm and AASc) 397
13.3.2 Rheology of new mortars and concrete 399
13.3.3 Mechanical behaviour: compressive and flexural
strengths 403
13.3.4 Stability (shrinkage) and durability of new alkaline
mortar and concrete 405
13.4 Concluding remarks 406
Acknowledgments 407
References 407
Further reading 424
14 Microstructural studies on recycled aggregate concrete 425
Luı ´ s Evangelista and M. Guedes
14.1 Introduction 425
14.2 Tools for microstructural characterisation of concrete 426
14.2.1 Optical microscopy 426
14.2.2 Scanning electron microscopy 427
14.2.3 Transmission electron microscopy 429
14.2.4 Atomic force microscopy 429
14.2.5 X-ray diffraction 430
14.2.6 Mercury intrusion porosimetry 430
14.3 Overview of microstructural features of natural aggregate
concrete 431
14.3.1 The microstructure of hydrated cement paste 431
14.3.2 The microstructure of paste/natural aggregate
interfacial transition zone 437
14.4 Microstructural and morphological features of CDW recycled
aggregates 440