## 5 Conclusions  
From the measurement of water absorption by the electrical conductivity method on three different fine aggregates (two recycled and one manufactured), measured on sieved fractions with both different particle size ranges and as a whole, the following conclusions are drawn.  
The water absorption measured in the aggregate as a whole and the weighted average WA value, considering the combination of variously sized fractions, are similar, which demonstrates the consistency of values to assess the variable particle size ranges.  
A good correlation between conductivity and moisture content was obtained for each sized sample analyzed. A sudden change occurs in accordance with the expected transition from the dominant internal moisture to the dominant external moisture. We can confirm that the method shows good potential to measure the WA of fine aggregates, irrespective of the particle size range within the studied size range of 4.75 mm-0.15 mm, and it is a more advantageous approach than the traditional cone method that earlier proved unsuitable for manufactured sands.  
The WA of NQ did not show significant variations in WA with the particle size, which connects with the homogeneous composition of the sand because of its natural origin. In contrast, the WA of RG and RQ showed significant increases in the fractions 0.30-0.15 mm as a result of their higher paste content (i.e., higher porosity).  
The lack of a clear trend regarding the slopes of dry and wet branches also indicates that geometry and particle size have no significant influence on the outcome of the electrical conductivity method.  
Different studies have concluded the potential of the electrical conductivity method to achieve an effective determination of WA, but uncertainties about the influence of different variables such as the shape and size of the particles on the measured WA remained. When applying other methods, these variables cause inaccurate values of WA, and, thus, the effectiveness of these methods has been widely questioned. In this research, the lack of a clear influence of the particle size and shape on the WA measured by the electrical conductivity method has been proven, with the paste content being the main variable that influenced the WA value. The method consistently showed good performance to achieve WA not only for RA but also for other manufactured sands.  
Further research is still needed to support the results of this study; for example, an interlaboratory test among several laboratories can establish accurate levels of the reproducibility of the electrical conductivity method as an intermediate step for standardizing the procedure. A reliable WA determination method is imperative to allow a sound assessment of the actual impact of fine recycled aggregates on concrete performance.  
Conceptualization, E.S. and Y.V.Z.; methodology, E.S. and L.C.; formal analysis, E.S.; investigation, E.S. and Y.V.Z.; resources, L.C. and C.Z.; data curation, Y.V.Z.; writing--original draft preparation, E.S. and L.C.; writing--review and editing, Y.V.Z. and C.Z.; supervision, C.Z. and Y.V.Z.; project administration, C.Z. and Y.V.Z. All authors have read and agreed to the published version of the manuscript.  
The authors express their gratitude for the financial support of FONCyT (PICT 2015-3339 and PICT 2017-0091).  
Not applicable.  
The authors declare no conflict of interest.