Multiple recycled aggregate properties analysed by X-ray microtomography

Abstract This paper presents a novel technique used to analyse the volume of adhered mortar to the recycled aggregate. A computerized microtomograph (μCT) device was used to evaluate the volume of the aggregate, the volume of natural aggregate and the volume of adhered mortar. To this end, a natural aggregate has been characterized, using the μCT, with which a source concrete has been produced. Subsequently, the source concrete has been crushed to obtain a first cycle recycled aggregate. After the characterization of the first-generation of recycled aggregate, a new source concrete has been made with it to be subsequently crushed again obtaining a second-generation recycled aggregates. In the same way a third-generation recycled aggregate has been obtained and has been equally characterized. The results show that the compaction capacity of the aggregate is reduced after successive recycling. It has been possible to quantify how much the closed porosity of the recycled aggregate decreases with the number of times it is recycled. The loss of natural aggregate and increase of the volume of adhered mortar have also been evaluated using this technique.

[1]  Valeria Corinaldesi,et al.  Structural Concrete Prepared with Coarse Recycled Concrete Aggregate: From Investigation to Design , 2011 .

[2]  P. Alaejos,et al.  Durability of recycled aggregate concrete , 2013 .

[3]  C. Tam,et al.  Removal of cement mortar remains from recycled aggregate using pre-soaking approaches , 2007 .

[4]  S. Barai,et al.  Recycled aggregate concrete incorporating fly ash: Comparative study on particle packing and conventional method , 2017 .

[5]  M. .. S. D. Rojas,et al.  Properties of interfacial transition zones (ITZs) in concrete containing recycled mixed aggregate , 2017 .

[6]  Jianzhuang Xiao,et al.  Fatigue behaviour of recycled aggregate concrete under compression and bending cyclic loadings , 2013 .

[7]  I. L. Morgan,et al.  Examination of Concrete by Computerized Tomography , 1980 .

[8]  D. Stefaniuk,et al.  Microstructural Analysis of Self-compacting Concrete Modified with the Addition of Nanoparticles☆ , 2017 .

[9]  Fernando López Gayarre,et al.  Use of recycled mixed aggregates in floor blocks manufacturing , 2017 .

[10]  P. Monteiro,et al.  Microstructural analysis of recycled concrete using X-ray microtomography , 2016 .

[11]  Chi Sun Poon,et al.  Effects of nano-particles on failure process and microstructural properties of recycled aggregate concrete , 2017 .

[12]  I. Lombillo,et al.  Fatigue limit of recycled aggregate concrete , 2014 .

[13]  José Dinis Silvestre,et al.  Compared environmental and economic impact from cradle to gate of concrete with natural and recycled coarse aggregates , 2017 .

[14]  Moisés Frías,et al.  Durability of recycled concrete made with recycled ceramic sanitary ware aggregate. Inter-indicator relationships , 2016 .

[15]  Stephen G. Azevedo,et al.  Computed tomography systems and their industrial applications , 1990 .

[16]  Mingzhong Zhang.  Pore-scale modelling of relative permeability of cementitious materials using X-ray computed microtomography images , 2017 .

[17]  J. Brito,et al.  Mechanical performance of concrete made with aggregates from construction and demolition waste recycling plants , 2015 .

[18]  J. A. Polanco,et al.  Structural recycled aggregate concrete made with precast wastes , 2016 .

[19]  J. Brito,et al.  Structural concrete with simultaneous incorporation of fine and coarse recycled concrete aggregates: Mechanical, durability and long-term properties , 2017 .

[20]  Belén González-Fonteboa,et al.  Shear strength of recycled concrete beams , 2007 .

[21]  J. de Brito,et al.  Use of coarse recycled aggregates from precast concrete rejects: Mechanical and durability performance , 2014 .

[22]  J. A. Polanco,et al.  Influence of recycled aggregates containing sulphur on properties of recycled aggregate mortar and concrete , 2013 .

[23]  J. de Brito,et al.  The influence of the use of recycled aggregates on the compressive strength of concrete: a review , 2015 .

[24]  J. A. Polanco,et al.  Evaluation of the fatigue behavior of recycled aggregate concrete , 2014 .

[25]  Belén González-Fonteboa,et al.  Time-dependent behaviour of structural concrete made with recycled coarse aggregates. Creep and shrinkage , 2016 .

[26]  M. Ohtsu,et al.  Fatigue characteristics of steel-making slag concrete under compression in submerged condition , 2014 .

[27]  C. Zega,et al.  Performance of recycled concretes exposed to sulphate soil for 10 years , 2016 .

[28]  J. Brito,et al.  Influence of the use of recycled concrete aggregates from different sources on structural concrete , 2014 .

[29]  Á. Salesa,et al.  Physico-mechanical properties of multi-recycled self-compacting concrete prepared with precast concrete rejects , 2017 .

[30]  Robert H. Crawford,et al.  Methodology for the integrated assessment on the use of recycled concrete aggregate replacing natural aggregate in structural concrete , 2017 .

[31]  V. Corinaldesi,et al.  The role of industrial by-products in self-compacting concrete , 2011 .