Masonry Magazine January 1965 Page. 49
What's Happening To High Bond Mortars?
Our mixing procedure is designed to take this variable into account by allowing for jobsite variation in the amounts of the local sand being used; in effect, we are adjusting the total void volume (which will vary from sand to sand) to fit a fixed amount of paste, as follows:
To a clean, dry mixer (rotating-blade type), add- 2½ cubic feet of sand (3-3/4 5-gallon pails) 1 cubic foot of portland cement (1 94-lb. sack) Dry mix these ingredients, and add - up to 1 gallon of water (depending on moisture content of sand) 1 container (4 gallons) Sarabond liquid polymer 1 50-lb. sack "A" Marble Dust Mix about four minutes, then adjust to suit workability requirements by adding up to 1 cubic foot (1½ -gallon pails) additional sand, plus any additional water required to maintain desired slump. The actual
strengths of Brick Mortars
Sarabond vs. Conventional
Hill
THE AUTHOR
A. A. "Bert" Hill is Section Head of Formulated Plastics Construction Materials for The Dow Chemical Company, Midland, Michigan. Mr. Hill received his B.S. degree in chemistry from Kent State University, and has been associated with the development of various construction materials for Dow during the past 12 years. He has been responsible for the high bond mortar development project since its inception. MCAA members will remember him for his excellent presentation on this subject at the 1963 Executive Board Meeting at Fontana, Wisconsin.
High bond mortar offers the mason a chance to demonstrate that his skills and art are important in
This figure shows a relative comparison of the strengths of high bond mortar made with Sorabend liquid polymer, and conventional cement/lime/sand mortar. In a fundamental sense, we are now mortaring masonry units together, not with a "weak link", rather with a material which itself matches the individual strengths of the masonry units. The structural engineer can, therefore, consider a wall of this type as being homogeneous in nature, much like he would consider a wall of poured concrete, for example.
The amount of sand required will depend on the individual characteristics of the sand itself, local climate conditions, and the suction rate of the masonry unit being used.
There are really three prime requirements for high bond mortar:
1. the right ingredients
2. the right mixing procedure, and
3. quality workmanship from skilled masons using only the best masonry practices.
It is important that a high bond mortar wall contain all head and bed joints. The cured mortar is itself virtually waterproof, and the joints in the wall will also be waterproof if the mason avoids leaving pinholes and voids in the mortar. You will find that high bond mortar tools about the same as conventional mortar, and you will want to use tooling techniques giving good quality joints particularly in exterior walls.
One possible end result of this new concept is illustrated by this photograph, taken on one of our experimental projects in Denver, Colorado. These 4"-thick wall sections were prefabricated at the brick yard by a mason contractor, then were trucked to the job site, lifted into place atop a multi-story building, and fastened by tack welding.