Construction Materials in the Port-au-Prince Metropolitan Area: Quarry and Alluvial Aggregates
Summary: An LNBTP characterization of the aggregates actually used to build in metropolitan Port-au-Prince, covering nine supply sites: seven open-pit quarries at Carrefour Dufort, Découverte, Fonds-Parisien, Laboule 12, Madan Gano, Morne à Cabri and Sanatorium, and two riverbed sources on the Rivière Froide and the Rivière Momance. Six bags, about 2 cubic meters, were taken at each site and tested mineralogically, chemically, physically and mechanically. Quarry material is more than 97 percent limestone of very good quality but only sometimes suitable for ordinary concrete, while alluvial material, under 20 percent limestone and rich in flint, is fully suited to it.
Key Findings
- The counterintuitive result is the finding. Quarry material is more than 97 percent limestone of very good quality yet only sometimes suitable for ordinary-quality concrete, and is above all a masonry material; alluvial material, with under 20 percent limestone and rich in flint ranging from brownish to clear, has characteristics fully suited to ordinary concrete. High limestone purity is therefore not the criterion a builder should select on.
- The strength ranges are close enough to matter for procurement: concretes made with quarry aggregate reach 23 to 26.4 MPa at 28 days and those made with alluvial aggregate 22.1 to 25.3 MPa. The overlap means site choice within each family matters as much as the choice between families.
- The study covers the sources that actually supply the city, which is what gives it standing: seven open-pit quarries, crushed originally massive limestone deposits, at Carrefour Dufort, Découverte, Fonds-Parisien, Laboule 12, Madan Gano, Morne à Cabri and Sanatorium, and two riverbed sources, Rivière Froide and Rivière Momance, described as the main aggregate supply for construction in the metropolitan area.
- The sampling is documented well enough to be repeated: six bags, about 2 cubic meters, per site, taken with manual pits and dragline-equipped mechanical shovels, bagged for transport, stored and tested at LNBTP, and treated as representative of their sites.
- The work is a by-product of the rubble-debris project financed in part by UNDP, and it draws on three state laboratories, LNBTP, BME and the Faculty of Sciences, over about four months. It presents itself as a technical reference for using materials of this type in Port-au-Prince.
- A record-quality note: this document's corpus title previously described it as geotechnical works and seismic risk in the Port-au-Prince area, which it is not. The title, summaries and findings have been rewritten from the document itself.
How to cite
National Laboratory for Buildings and Public Works (LNBTP), 2014, Construction Materials in the Port-au-Prince Metropolitan Area: Quarry and Alluvial Aggregates, https://lnbtp.gouv.ht/publications/GeoRegina14Paper121.pdf