Flexural load tests of full-scale recycled aggregates concrete structures

• Full-scale tests of eight concrete slabs made with recycled aggregates.
• Influence of the replacement ratio and of superplasticizers.
• The influence of the aggregates was smaller than that of the execution conditions.
• The use of 100% coarse recycled concrete aggregates in structural slabs is feasible.

In order to study the behaviour of concrete structures made with coarse crushed concrete aggregates recycled from discarded elements from the precasting industry, extensive testing was performed in four full-scale structures with varying recycled aggregate (RA) ratios. This paper describes and analyses the results of vertical load tests on each slab of these double-floor structures. The Young’s modulus (E) of the concrete mixes was estimated by finite element model calibration using deflection data from the tests. The response pattern of the various structures was the same and the aggregates used had a small influence on E, even smaller than the execution conditions. One of the concrete mixes included a superplasticizer (SP) and this product more than offset the loss of stiffness due to RA use. To the authors’ best knowledge this is the first study ever concerning the behaviour of full-scale recycled aggregate concrete (RAC) structures subjected to vertical loading and the behaviour of slabs with significant replacement of conventional aggregates by RA.