Page 236 - New Trends in Eco efficient and Recycled Concrete

204 New Trends in Eco-efficient and Recycled Concrete

they have heat-treated them at 250 300 C. The most appropriate treatment would
be a simple treatment of the shells, involving low energy consumption resulting in
a commercially safe by-product.
The effects of the use of recycled shells in concrete has been analysed. Firstly,
the hardened density is severely reduced with the percentage of substitution of
aggregate and the greater the size of the same. This same effect was observed in
the fresh-state properties.
The effect of the mollusc shells in compressive resistance is similar for all spe-
cies. It can be seen that the greater the percentage of substituted aggregate, the
greater the decrease in compressive strength at both 7 and 28 days. This effect is
enhanced in the case of coarse aggregate, which influences more than fine aggre-
gate due to the influence of the flaky shape of the shells.
The use of mollusc shells as aggregates affects the microstructure of the con-
crete. There is a reduction in bonding with the nacre layer of the shell and this pro-
duces higher porosity and affects the mechanical properties.

References

Adewuyi, A.P., Adegoke, T., 2008. Exploratory study of periwinkle shell as coarse aggregate
in concrete works. ARPN J. Eng. Appl. Sci. 3 (6), 1 5.
Agbede, O.I., Manasseh, J., 2009. Suitability of periwinkle shell as partial replacement for
river gravel in concrete. Leonardo Electron. J. Pract. Technol. 8 (15), 59 66.
Barnaby, C., 2004. An Investigation into the Reuse of Organic Waste Produced by the New
Zealand Mussel Industry. Thesis. Auckland University of Technology.
Cuadrado-Rica, H., Sebaibi, N., Boutouil, M., Boudart, B., 2016. Properties of ordinary con-
cretes incorporating crushed queen scallop shells. Mater. Struct. 49 (5), 1805 1816.
Elliott Richardson, A., Fuller, T., 2013. Sea shells used as partial aggregate replacement in
concrete. Struct. Surv. 31 (5), 347 354.
FAO, 2015. Fisheries and Aquaculture Statistics. Available at: ,http://www.fao.org/3/
a-i7989t.pdf..
FAO, 2018. Global Aquaculture Production 1950 2016 Database. Available at: ,http://
www.fao.org/fishery/statistics/global-aquaculture-production/query/es..
Falade, F., 1995. An investigation of periwinkle shells as coarse aggregate in concrete. Build.
Environ. 30 (4), 573 577.
Ge ´nio, L., Kiel, S., Cunha, M.R., Grahame, J., Little, C.T.S., 2012. Shell microstructures of
mussels (Bivalvia: Mytilidae: Bathymodiolinae) from deep-sea chemosynthetic sites: do
they have a phylogenetic significance?. Deep Sea Res., Part I 64, 86 103.
Hazurina-Othman, N., et al., 2013. Cockle shell ash replacement for cement and filler in con-
crete. Malaysia. Malaysian Journal of Civil Engineering, 201 211.
Kelley, K.N., 2009. Use of Recycled Oyster Shells as Aggregate for Pervious Concrete.
Master Thesis. University of Florida.
Martı ´nez-Garcı ´a, C., Gonza ´lez-Fonteboa, B., Martı ´nez-Abella, F., Carro- Lo ´pez, D., 2017.
Performance of mussel shell as aggregate in plain concrete. Constr. Build. Mater. 139,
570 583.