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Circular Economy
After the comparative analysis of the different pre-soaking methods, the results obtained have shown that RA pre-soaking only benefited the early age resistances. Moreover, workability was improved when RA was pre-soaked for 10 minutes with an additional content of pre-soaking water (according to its greater water demand). The use of not pre-soaked RA gave rise to low workable concretes.
Consequently, and in order to get RAC of adequate durability subjected to any type of exposure (EHE-08), an adjustment in the dosage provided by the manufacturer should be made. In this sense, an optimization in the a/c ratio and in the cement content to minimize the environmental impact, have been recommended. In addition, an adjustment in the additive content was necessary, both to compensate the loss of free water in the mixture due to the greater water absorption of the RA and to ensure a soft consistence. Finally, the use of not pre-soaked RA was recommended, due to the greater complexity and the higher costs involved in the implementation of pre-soaking technique on the concrete manufacturing plants.
3. Acknowledgment
We would like to thank the Departments of Building Construction and Civil Engineering of Granada University for their cooperation in this study.
4. References
Agrela, F., Sánchez de Juan, M., Ayuso, J., Geraldes, V.L., Jiménez, J.R. (2011), Limiting properties in the characterisation of mixed recycled aggregates for use in the manufacture of concrete. Construction and Building Materials, 25 (10), pp 3950–3955.
Poon, C.S., Kou, S.C., Lam, L. (2002), Use of recycled aggregates in molded concrete bricks and blocks. Construction and Building Materials, 16 (5), pp 281–289.
COM 614 (2015), Cerrar el círculo: Un plan de acción de la UE para la economía circular. Comisión Europea, Bruselas, p 24.
EHE-08 (2008), Instrucción de Hormigón Estructural. Ministerio de la Presidencia, BOE, 203 (22 de agosto), pp 35176–35178.
Sánchez-Roldán, Z., Martín-Morales, M., Valverde-Palacios, I., Valverde-Espinosa, I., Zamorano, M., (2016), Study of potential advantages of pre-soaking on the properties of pre-cast concrete made with recycled coarse aggregate. Materiales de Construccion, 66 (321), p 13.
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