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No significant correlations between the w/b ratio and the binder content with 𝑓 were found: the 𝑐
respectivecorrelationcoefficientswerebelow0.3.Kwasdefinedasindependentof𝑓 forconvenience 𝑐
andbecausethecoefficientofcorrelationbetweenKand𝑓 wasalsonotmeaningfulalso-0.35(NAC) 𝑐
and 0.36 (CRAC). Scatterplots did not show evidence of nonlinear correlations.
Normal distribution plots agree with K being modelled as normally distributed (Fig. 2). The proposal
of the deterministic and probabilistic versions of K is shown in Table 1.
4 3 2 1 0
-1 -2 -3
NAC - data
NAC - normal distribution CRAC - data
CRAC - normal distribution
0,6
0,7 0,8
K
0,9 1,0
Figure 1 K vs. cubic compressive strength and type of binder
Figure 2 Goodness-of-fit: normal distribution
Table 1 Proposed K factor
Model
Deterministic factor Probabilistic model (Normal)
4. Acknowledgments
Parameter NAC CRAC
Mean
Conservative factor Mean
Standard deviation
0.81 0.77 0.79 0.76 0.81 0.77 0.065 0.055
The authors gratefully acknowledge the support of the CERIS research centre, of IST - University of Lisbon, and of the EcoCoRe doctoral program (grant PD/BD/113643/2015) financed by FCT.
5. References
EN-206-1. (2000). Concrete - Part 1: Specification, performance, production and conformity (72 pages). Brussels, Belgium: Comité Européen de Normalisation (CEN).
EN-1992-1-1. (2008). Eurocode 2 - Design of concrete structures: Part 1-1: General rules and rules for buildings (259 pages). Brussels, Belgium: Comité Européen de Normalisation (CEN).
Gull, I. (2011). Testing of strength of recycled waste concrete and its applicability. Journal of Construction Engineering and Management, 137(1), 1-5.
Kheder, G. F., & Al-Windaw, S. A. (2005). Variation in mechanical properties of natural and recycled aggregate concrete as related to the strength of their binding mortar. Materials and Structures 38(281), 701-709.
Muhammad, A. K., & Sankaranarayanan, K. M. (2016). Investigations on concrete with recycled concrete as coarse aggregate. International Journal of Scientific & Engineering Research, 7(10).
Paul, S. C. (2011). Mechanical behaviour and durability performance of concrete containing recycled concrete aggregate. (MsC), University of Stellenbosch, Cape Town, South Africa.
Pedro, D., de Brito, J., & Evangelista, L. (2014). Influence of the use of recycled concrete aggregates from different sources on structural concrete. Construction and Building Materials, 71, 141-151
Rao, D. V. P., & Desai, P. L. S. (2014). Experimental investigations of coarse aggregate recycled concrete. International Journal of Advances in Engineering & Technology, 7(5), 1522-1530.
Santos, S., da Silva, P., & de Brito, J. (2017). Mechanical performance evaluation of self-compacting concrete with fine and coarse recycled aggregates from the precast industry. Materials, 10(8), 904.
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