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South and Central America
Published in Ian Sims, Alan Poole, Alkali-Aggregate Reaction in Concrete: A World Review, 2017
Rock types were identified as cataclastic gneiss, mylonite, cataclasite, porphyritic granite and gneiss mylonite. The coarse aggregates always contained strained quartz minerals with undulating extinction in their composition, most of the time associated to microcrystalline and recrystallized quartz in a matrix structure. It was verified that all the concrete samples taken from the buildings presented evidence of AAR, either from petrographic analysis, or by optical and SEM microscopy. Additionally, the analyses carried out with the fine and coarse aggregates indicated their potential reactivity. Andrade et al. (2008) concluded that “alkali-aggregate reaction is now an additional likely cause of cracking in the reinforced concrete structures of Recife, especially for those in permanent contact with water, such as the concrete elements of buildings foundations and concrete monuments”.
Metamorphic Rocks
Published in F.G.H. Blyth, M. H. de Freitas, A Geology for Engineers, 2017
F.G.H. Blyth, M. H. de Freitas
Dislocation metamorphism occurs on faults and thrusts where rock is altered by earth movement (see Figs 1.20 and 2.3). Much energy stored in the surrounding crust is released along these zones and dislocation metamorphism is associated with earthquakes (Chapter 1). Within 10 km of the Earth’s surface these movements involve brittle fracture of rock, the mechanical breaking caused by shearing, grinding and crushing being termed brecciation or cataclasis (= breaking down). Major shear zones continue to great depths and below 10 km pressure and temperature may be sufficient for dislocation to occur by plastic deformation. Fine-grained rocks are produced, called mylonites (Greek, mylon = mill).
Nappe units along the Caledonian margin in central Scandinavia (Grong–Olden to Nasafjället): definition, distinction criteria and tectonic evolution
Published in GFF, 2018
Reinhard O. Greiling, Benno Kathol, Risto A. Kumpulainen
The floor thrust of the Stalon Nappe is similarly developed as the internal thrusts in the Blaik Nappe and other related nappes (Fig. 7A). It is dominated by brittle, cataclastic fault rocks, composed of brecciated fragments of alum shale, quartzite and arkose.