Environmentally eco-efficient concrete is currently a popular choice of construction material. Reviewing relevant literature indicates that heating of cement paste can remove hydrating water, and that quartz sand of appropriate granulometry can act as a supplementary cementitious material; however, there have been virtually no reports on the reuse of these materials as alternative binders. This work evaluates the phases present in cementitious compounds produced with binders obtained by thermomechanically treating cement pastes with and without a 15% substitution of quartz sand powder (specific surface area 37.4 m²/g), referred to as RCQ and recycled cement RC, respectively. Testing included thermogravimetric analysis (performed with stripped gases), X-ray diffraction, and scanning electron microscopy with phase identification. The obtained data indicated RC cement paste possesses a predominantly ettringite microstructure, whereas the presence of calcium hydroxide and hydrated calcium silicate predominates in RCQ paste.

ResumoThis paper describes the adherence behavior of a structural lightweight concrete with EPS beads (SLCEB) in a monotonic loading, based in a bibliographic review and in pull-out tests. The results of these SLCEB tests were compared with those of an ordinary concrete (OC) and with the values based in indications of the Brazilian code ABNT NBR 6118:2014 -Design of concrete structures. The pull-out tests of two batches of SLCEB and one of OC were analyzed, in a total of 60 tests. Mechanical characteristics were determined too, such as: compressive strength and tensile strength in split cylinder test. The calculated results according to the above mentioned standard were very different from those obtained in the tests, indicating that the theoretical values are more conservative than the experimental ones. It was also verified that it is possible to use SLCEB in structures with respect to the adequate adherence of reinforcement in the concrete.Keywords: lightweight concrete with EPS, anchoring by adherence, sliding, splitting, adherence stress.Este artigo descreve o comportamento da aderência de um concreto leve estrutural com pérolas de EPS (CLEPE) sob carregamento monotôni-co, com base em revisão bibliográfica e em ensaios de arrancamento. Os resultados desses ensaios de CLEPE foram comparados com os de um concreto convencional (CC) e com os valores baseados nas recomendações da ABNT NBR 6118:2014 -Projeto de estruturas de concreto. Foram analisados os ensaios de arrancamento de dois lotes de CLEPE e um de CC, totalizando 60 ensaios. Também foram determinadas características mecânicas, tais como: resistência à compressão e resistência à tração por compressão diametral. Os resultados calculados de acordo com a norma citada foram muito diferentes dos obtidos nos ensaios, indicando que os valores teóricos são mais conservadores do que os experimentais. Verificou-se também que é possível usar o CLEPE em estruturas, no que diz respeito à adequada aderência da armadura ao concreto.Palavras-chave: concreto leve com EPS, ancoragem por aderência, deslizamento, fendilhamento, tensão de aderência.