ACI SP-147

Abstract

<strong>INTRODUCTION</strong> <br>Masonry is one of the most widely used construction materials in the Americas, however because the development of its use followed different paths in each country, and even within the same country, the diversity of materials and construction techniques is broad when seen in a continental basis. Some of the matenals employed in masonry construction are essentially the same in all the American countries and are manufactured following similar standards, as is the case of Portland cement and reinforcing steel On the other hand, the masonry units and the type of aggregates for mortar and grout are different from country to country, even though the same names are used to describe them. The quality of workmanship varies enormously in the Americas and specially from urban to rural areas in the same country. These characteristics render masonry construction difficult to compare from country to country. This is specially true for the materials used in masonry construction. <br>Materials used in masonry construction can be divided in four groups: masonry units, mortar, grout and reinforcement Masonry units can be grouped together depending on the material employed, their geometry and the distribution of cores, when used. Following this distribution and considering the production technique, general characteristics and mechanical properties can be established. Mortar and grout also present a great variability depending on the aggregates employed, mix proportions and quality of workmanship. North American standards have had a great influence in the type of mix proportions employed and most countries describe their mortars in the same way This has improved the quality of mortars throughout the Amencas, although in some countries mortars made out of non typical materials are still used <br>Reinforcement is available in different grades and characteristics, conforming to local standards, all of them very similar to ASTM A615. In those countries that do not have local steel mills, imported steel is used, thus making the diversity of quality even broader, specially when Japanese or European steels are used. The employment of the same type of reinforcing steel in reinforced concrete structures guarantees its availability. The changes that are currently occurring throughout the Americas, concerning the release of trade barriers, will have a large impact in the unification of manufacturing standards for construction matenals, at least in neighboring countries