LIBERATION OF CEMENT PASTE IN RECYCLED AGGREGATES BY DIFFERENT COMMINUTION METHODS

Author(s): Paula O. Figueiredo, Carina Ulsen, Rafael S. Macedo, Guilherme P. Nery, Maurício G. Bergerman
Paper category: Proceedings
Book title: IV International Conference Progress of Recycling in the Built Environment
Editor(s): Isabel M. Martins, Carina Ulsen, Yury Villagran
ISBN:
e-ISBN: 978-2-35158-208-4
Publisher: RILEM Publications SARL
Publication year: 2018
Pages: 54-61
Total Pages: 08
Language : English

Abstract: The depletion of mineral reserves for construction near large urban centres in addition to
increasing exploitation restrictions has increased the transportation distance between the
mining sites and the consumer market. Therefore, recycling construction and demolition
waste (CDW) is a possible alternative for substituting aggregates in building materials. The
main limitation regarding the use of recycled aggregates (RA) refers to their technological
properties derived mainly from the porous residual cement paste. The properties of CDW
aggregates can be improved by choosing the appropriate comminution equipment for
selectively removing the residual cement paste attached to the particles surface. This work
thus aims to compare CDW RA processed in jaw and impact crushers configured to generate
two products with the same top-size. Consecutively, the crushed products were subjected to a
low energy selective milling. The results show that the aggregates produced in both crushing
routes have similar properties, such as enrichment of natural aggregate in fractions below 1.2
mm and cement paste in the fraction below 0.075 mm; this tendency intensified after selective
milling. Thus, minor differences observed do not justify the common belief in the industry
that impact crushers provide an improvement in the quality of RA; low energy selective
milling indicates additional removal of cement paste from aggregates surface but process
optimization must be carried out.

Online publication : 2018
Publication type : full_text
Public price (Euros) : 0.00