Masonry Magazine October 1996 Page. 28
Code Conformance
The Code allows for two methods of grouting, high lift and low lift. Each has advantages and benefits.
Grout lift and grout pour are terms defined by the Code. A grout lift is the portion of grouting done in a single operation. A grout pour, which is made up of one or more grout lifts, is the amount of grouting typically done in a single day.
When masonry walls are grouted, they may be partially grouted, where the grout is confined to only the cells containing structural reinforcement, or they may be solid grouted, where grout is intended to fill all cells or cavities.
Cleanouts are not required with the low lift grouting method, however the pour is limited to a 5 foot maximum. If the mason contractor desires to construct the walls higher than 5 feet before grouting, the high lift method should be used.
The high lift grouting method required cleanouts at the base of the wall. The purpose of these openings is to remove the accumulated debris at the base of the wall prior to grouting. When the base of the grout space is free of debris, the grout forms a bond with the footing, thereby enhancing the structural integrity.
Prior to grouting, the cleanout holes are sealed using a unit face shell, or simply by blocking the hole, typically with a piece of form lumber, if the finish of the wall is not an issue, such as a wall that is to receive plaster.
The moment of truth for reinforced structural masonry comes during the grouting process. The grout must be extremely fluid, with a slump of 8 inches to 11 inches in order to find the way to every intended space in the cells containing steel. In order to remove all air voids in the grout, the Code requires mechanical vibration and mechanical reconsolidation of grout pours over 1 foot. In certain areas of high congestion, such as around electrical panels with conduit feeding into the wall, hand puddling the grout will accomplish the intent and substantially reduce the chance of a blowout.
In order to achieve the consolidation quality of grout, it is extremely important to reconsolidate the grout immediately after the initial water loss, which is usually only a couple of minutes after the initial consolidation.
There is a continuous debate about the frequency of testing. The Code currently states that testing of prisms or mortar or grout will be done every 5,000 square feet of wall area, when required. This gives the owner and designer assurance that the mason contractor is delivering the intended structural integrity of the building.
In the interest of economic savings, the testing programs are often not required.
The answer is... Yes! The Code Specification contains items that are intended to guide the mason contractor and determine the minimum standards of construction. It is essential that the mason is aware of his or her Code responsibilities. As the mason contractor becomes knowledgeable of, and practices the Code requirements, the quality of masonry improves, which is a benefit to the industry.
There are many other construction issues addressed by the Code that are not contained in this article. A thorough apprenticeship program and invaluable field experience are complementary to Code Specification requirements.
The Masonry Institute of America can be reached through e-mail at 103623.3262@compuserve.com, or can be accessed through our website, http://www.bricknet.com/MIA.html.
The opinions expressed in this article are those of the author and are not intended to encompass all aspects of the Code. Questions and clarifications of the Code should be referred to the local Building Official for jurisdictional interpretation.
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