Page 68 - New Trends in Green Construction

Circular Economy
During the pouring, samples were casted and after 24 hours, stored in humid chamber. Tests such as compressive and splitting tensile strength were conducted after 90 days, and modulus elasticity and sorptivity (UNE-EN 1925:1999) were performed after 28 days of curing. Three specimens were used for each test.
3
Table 1. Composition of the concrete mixes.
CC=Control concrete, RC= Recycled Concrete, R.R. = Coarse Ratio Replacement.
R.R. Proportions (kg/m3)
(%) Cement A/C Water NS NG MRA Pl. Spl. Cone(cm)
0 200 0.45 90 1100 950 0 1.92 2.15 4 100 202 0.45 91 1100 0 720 1.92 2.15 6
Samples
CC RC
Abrams
3. Results and conclusions
Figure 2 shows the results of the mechanical tests carried out. RC presented a gain of 22% between 90 days and 28 days, whereas CC presented lower increase (14%) in compressive strength. The decreases in splitting tensile strength in CC were lower than 20% respect to those of RC for the ages studied. A greater reduction took place in modulus of elasticity comparing CC with RC results, 19.1 GPa in RC versus 11.1 GPa in RC. In the sorptivity test
−1/2
−1/2
results, 0.42 mm·h
obtained was in accordance to the bibliography (López-Uceda et al., 2016, Etxeberría et al., 2013). No inconveniences were found during placing the RC mix. These results support the feasibility of the use of MRA in concrete applied in non-structural purposes like ditches.
Figure 2. Compressive and splitting tensile strength over time in samples.
4. Acknowledgment
The authors would like to thank the Regional Ministry of Public Works of the Government of Andalusia, and PREBESUR SL, for its support in the concrete mix supply.
5. References
European Commission (DG ENV) (2011) Final Report Task 2: Service Contract on Management of Construction and Demolition Waste Prepared by Bio Intelligent Service. Available online: http://ec.europa.eu/environment/waste/pdf/2011_CDW_Report.pdf.
Etxeberria, M., Gonzalez-Corominas A.; Valero López I. (2013) Application of low grade recycled aggregates for non-structural concrete production in the city of Barcelona. In Proceedings of the Third International Conference on Sustainable Construction Materials and Technologies.
López-Uceda, A., Ayuso, J., Jiménez, J., Agrela, F., Barbudo, A., & De Brito, J. (2016).Upscaling the use of mixed recycled aggregates in non-structural low cement concrete. Materials, 9(2), 91.
and 0.80 mm·h
were obtained for CC and RC respectively. The data
68