Assessment of the influence of recycled aggregate on the resistance to external sulfate attack by accelerated testing of mortar bars

LAUTARO R. SANTILLAN; Y.A. VILLAGRÁN ZACCARDI; C.J. ZEGA

Delft

Congreso; 4th International Conference on Service Life Design for Infrastructures; 2018

RILEM

Concrete exposed to external sulfate attack requires a reduced porosity to lessen the penetration rate of sulfate, and a limited aluminate supply to avoid formation of deleterious products. These two aspects are worsened with the inclusion of recycled concrete aggregate (RCA).Most of evaluation methods for sulfate attack described in the literature, including those proposed for aggregate, are mainly focused on salt crystallization and not on chemical attack. In addition, there is scarce research on the influence RCA on the sulfate resistance of concrete, with no accelerated methodology available for the assessment of the potential effect of RCA on this matter.With this aim, this paper presents a study on the performance against sulfate attack of RCA mortar bars. The studied variables include RCA content, exposure in immersion and in soil, specimen slenderness, and cement type. A reduced testing time was achieved by testing mortar specimens containing recycled fine aggregate with a relatively high specific surface. The condition of specimens was analyzed by visual inspection, and changes in length and weight up to 1 year of exposure. Results show a low influence of the content of RCA, smaller than the type of exposure and the slenderness ratio of the prisms.