MAIA, R, L. C.; http://lattes.cnpq.br/6245535547375630; MAIA, Rafael Luís de Carvalho.
Résumé:
The Alkali-Aggregate Reaction (AAR) is a chemical process of concrete
deterioration which had its first records in the beginning of the 20th century, and it
was primarily identified in dams, bridges, port structures and, more recently,
foundation blocks. It is basically the reaction product of alkalis in the concrete,
reactive minerals in aggregates and water, and generates an expansive effect to
which there is no existing solution. Due to this, prevention is the main tool available
to stop AAR from occurring, therefore the aggregate reactivity, among other things,
must be readily identified. Sustainability is a topic in growing evidence, and the use
of aggregates from the recycling of solid residues (or Construction and Demolition
Waste – CDW) is na alternative to the destination of these, thus being needed that
such aggregates have their potential reactivity assessed. In this work, two CDW
aggregates were tested, which were Concrete Residues and Masonry Residues.
Furthermore, testing was done on sand and gravel frequently used in constructions
in the city of Campina Grande – PB. The method used for testing was the
Accelerated Mortar Bar Test, which is done by submerging mortar bars cast with the
aggregates to be tested in a sodium hidroxyde solution heated to 80°C.
Measurements of expansion of the bars, for all aggregates, were taken daily until 16
and 28 days of submersion. From the measurements obtained and the 0.10%
expansion limit stablished in ABNT NBR 15577, the aggregates did not show as
potentially reactive.
