In recent decades the problem of construction and demolition waste has been receiving more attention due to possible ecological and economic damage caused by them. This is because they are produced in large quantities and often receive inadequate disposal, being deposited illegally in vacant lots, public places and even in areas of environmental preservation. The practice of recycling of construction and demolition waste (CDW) by construction is an alternative that minimizes the amount of waste generated and the impacts caused by them. Moreover, the introduction of alternative materials might reduce the production costs of construction. In Brazil, there is great availability of lateritic concretions. This material, according to some studies, proved to be a viable alternative to be used as coarse aggregate in concrete production. In this study, it is used the CDW as a filler to replace 10% of Portland cement and, as coarse aggregate, lateritic concretions. Tests of physical properties of coarse and fine aggregates and determination of the mechanical strength of hardened concrete were made. The construction and demolition waste used as filler to replace the mass of cement in the mixture proved to be a viable alternative.

The concern about the environment has been leading the construction industry to adopt more sustainable practices. The main environmental impact of concrete is related to CO2 emissions coming from cement, particularly from the cement content in concrete. For this reason, this research evaluates the performance of concretes with partial replacement of Portland cement by limestone filler and silica fume. These concretes were proportioned to improve particles’ packing and paste volume optimization. The compressive strength was determined to assess their mechanical performance. Their durability was investigated by capillary absorption and chloride penetration resistance. Results indicate that concretes showed a better efficiency in terms of binder intensity, with values close to the minimum found in literature (5 kg.m-3.MPa-1). It was also observed that even concretes with cement content lower than the minimum recommended by standards showed better performance than regular concretes regarding the chloride’s penetration.

A corrosão é uma das principais causas de deterioração das estruturas de concreto armado. Devido a isso, várias tecnologias vêm sendo desenvolvidas para reduzir a incidência da corrosão nas armaduras. A galvanização à quente das barras tem sido apontada como uma alternativa viável para estruturas submetidas a meios de elevada agressividade. Apesar de apresentar vantagens significativas sobre as armaduras convencionais, como o incremento do período de iniciação da corrosão, ainda há uma carência de informações sobre o desempenho dessas barras frente à ação dos cloretos. Diante deste cenário, esta pesquisa avaliou o comportamento eletroquímico de barras galvanizadas e não galvanizadas, submetidas à diferentes alcalinidades. Foi verificado o seu desempenho frente à carbonatação e à ação dos íons cloretos, em distintas concentrações. Os resultados demonstraram que diante da baixa alcalinidade, a armadura comum inicia o processo de corrosão, enquanto que a armadura galvanizada se manteve passiva. Porém, para meios muito alcalinos, o aço carbono demonstrou ser mais indicado. Além disso, diante da ação dos cloretos, apenas a armadura em aço despassivou quando se alcançou uma relação [Cl-]/[OH-] de 0,5 na solução. Outras concentrações de cloretos estão sendo estudadas até alcançar o limite crítico de cloretos

<p>Taking into account the few studies carried out about hot-dipped galvanized reinforcements, this work aimed to study the behaviour of these reinforcements in different alkalinity media and subjected to subsequent carbonation. For this purpose, galvanized and carbon reinforcements were immersed in alkaline solutions and electrochemically monitored to evaluate their behaviour. Results show that galvanized reinforcements present good performance in carbonated media and also in media with pH lower than 13.3, which presented corrosion potential under levels that indicate a passive state of reinforcementsregarding corrosion. On the other hand, carbon reinforcements present corrosion activity in carbonated media and passive condition in medias with pHs over 12.5.</p>

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