Author(s)

L. Holliday, C. Ramseyer & F. H. Grant

Abstract

Most of the building failures in Haiti during the January 12th, 2010 earthquake were CMU block buildings. It is the locally preferred building material. Since it is difficult to import materials into Haiti, CMU block is made with local sand (sometimes beach sand which includes a significant amount of salt) and aggregate and only requires Portland cement to be imported. The blocks are made in a press-type machine without steam and at comparatively little pressure. The blocks contain as little as 1/30th Portland cement by volume and are left in a yard to dry cure, rather than moist curing. The blocks are sometimes so weak that they must be handled by workers with two hands or they break under their own weight. Tests at the University of Oklahoma reveal the blocks have an extremely low compressive strength (as low as 300 psi). Given the typical construction techniques used in Haiti, which include heavy concrete slab roof, focusing on hurricane resistance rather than earthquakes, the current CMU block fabrication method was a recipe for disaster that was realized. OU researchers worked with local Haitian organizations, primarily at Christianville Mission, to improve the quality of CMU blocks in Haiti. They provided guidelines for the CMU block mix, and curing instructions. Tests show the compressive strength of the CMU block has increased by more than three times with relatively little additional cost. This paper discusses the problems with current fabrication techniques for CMU block in Haiti, changes which can be made with relatively little cost or effort, and the resulting improvements in block strength realized. Keywords: masonry, Haiti, earthquake.

Keywords

masonry, Haiti, earthquake