Paper by MORALES CICILIATO ANGULO from ISCR 8th 1998 Lisbon Portugal
The objective of the present work is the study of the technical viability of the use of refused material of building construction like aggregates for concrete roads. The first stage consisted of the physical characterization of the aggregates obtained through the grinding, followed by a study of the granulometric composition using recycled material and natural sand. To proceed there were defined different rates of the recycled aggregate in the concrete composition, the ideal sequence of the mixture and the workability conditions, being appraised the properties of the concrete in the fresh state. Finally, there were appraised the properties of the concrete in the hardened state. The produced aggregate was classified in four fractions through screening in the sieves of mesh 9,5mm, 48mm, 4mm and 1,2mm. The text of powdery material, passed in the sieve 0,075mm was of 12% to 23%. There was rehearsed the unitary mix design initially in mass 1:1,5:2 with several compositions among the produced fractions, as well as compositions using washed sand of river, and the most promising results were obtained by using four fractions with and without incorporation of natural sand. There were obtained strength of axial compression by the order of 18 to 20 MPa, with quite favuiable tesulls when using the thinnest fractions, being attributed the fact to a certain pozzolanic reactivity coming of the ceramic material present in the refused material.