Abstract

This work studies the physical and mechanical properties of recycled concrete aggregate (recycled aggregate from concrete waste) and their influence in structural recycled concrete compressive strength. For said purpose, a database has been developed with the experimental results of 152 works selected from over 250 international references. The processed database results indicate that the most sensitive properties of recycled aggregate quality are density and absorption. Moreover, the study analyses how the recycled aggregate (both percentage and quality) and the mixing procedure (pre-soaking or adding extra water) influence the recycled concrete strength of different categories (high or low water to cement ratios). When recycled aggregate absorption is low (under 5%), pre-soaking or adding extra water to avoid loss in workability will negatively affect concrete strength (due to the bleeding effect), whereas with high water absorption this does not occur and both of the aforementioned correcting methods can be accurately employed.

Highlights

  • The processed database results indicate that the most sensitive properties of recycled aggregate quality are density and absorption

  • The creation of a database [3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154] including these published results (Figure 1) is very useful for making general conclusions. The objective of this database analysis is to achieve a full understanding of recycled concrete aggregates and propose a design methodology for structural recycled concrete, based on the physicalmechanical properties of recycled concrete coarse aggregates studied using the database

  • This paper deals with the study of aggregates recycled from concrete waste, which are the most suitable aggregates for creating structural recycled concrete

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Summary

Composition

Recycled aggregates are defined as aggregates obtained from the treatment of inorganic material which has been previously used in construction [159]. Regarding the particular case of recycled concrete aggregate, this is obtained from the recycling process of concrete waste material. The recycled concrete aggregates are mainly made of natural aggregate and adhered cement mortar It may incorporate impurities and contaminants, which have a negative influence on the properties of the final recycled concrete [149]. In the case of recycled aggregates suitable for recycled concrete, a minimum material from concrete waste of 90% is usually imposed (Brazilian, German, Rilem and Belgian standards) and a maximum of 10% masonry material is established. With a suitable crushing process, the recycled coarse aggregates from waste concrete can deal with these limits

Adhered mortar
Shape and particle size distribution
Water absorption
Saturated surface dry density
Abrasion resistance
Findings
CONCLUSIONS
Full Text
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