Masonry Magazine February 1972 Page. 18
THE HIGH
BOND CLASSROOM
a monthly feature by Amspec
In the last issue we reviewed the importance of following the mixing instructions which are printed on each package of SARABOND® brand high bond mortar additive. In the next few issues we will discuss the importance of the portland cement, mason sand, and limestone which are blended into the mix with SARABOND.
One of the most important ingredients used with SARABOND is portland cement, which is manufactured according to a special process invented in 1824 by Joseph Aspdin, a bricklayer. The special controls of inter-grinding, blending, kiln-burning and controlled cooling make portland cement more uniform, stronger and faster setting than cements referred to as "natural" cements. For this reason, only portland cement should be used in high bond masonry.
Constant revisions of the specifications for portland cement have brought about five major categories or types of portland cement. Each type is specially formulated for a specific application:
Type I This is the oldest of portland cement types and is used for general concrete construction as well as with SARABOND.
Type II- This cement is used for construction requiring moderate sulfate resistances and somewhat lower heat of hydration. This cement should NOT be used with SARABOND. SARABOND offers good sulfate resistance and heat of hydration is not a problem in mortar.
Type III This is high early-strength cement and can be used with SARABOND when temperatures are below 60°F. The faster curing properties of this cement offer advantages in winter construction because the mortar prepared with Type III cement need not be protected from cold temperatures as long as mortar prepared with Type I cement.
Type III is also used in some masonry prefabrication because the panels cure faster and can be moved earlier. Because of the faster cure, board life may be reduced at high temperatures.
Type IV- This cement is used for application where low heat of hydration is required. This is necessary in massive concrete structures such as dams, where heat of hydration can boil water. This cement should NOT be used with SARABOND.
Type V This is a very high sulfate resistant cement, similar to Type II. This cement should NOT be used with SARABOND.
As you can see, only fresh Type I and Type III portland cement are used with SARABOND. This cement should always be free from lumps and protected from moisture intrusion. (Be wary that mortar color differences may occur among Type I, Type III and different suppliers and brands.) Prepared and proprietary masonry cements contain known and unknown ingredients detrimental to the strength of high bond mortars. Air entraining or waterproof cements and masonry or mortar cements are not permitted.
But now, for the exception to the rule: Medusa Portland Cement Co. and Riverton Corporation are in the process of developing convenient mortar mixes which will contain portland cement, an approved workability additive and integral color pigments for use specifically with SARABOND.
Senior Citizen Housing
(Continued from page 17)
The Housing Authority, under Wm. W. Willis, recently completed the Dwight D. Eisenhower and the George M. Rhodes Apartments with Eshbach Brothers (MCAA) as mason contractor and Frank Favazza as general contractor. The twin high-rises were designed by architect Morris Steinhorn, AIA, with Michael Johns as structural engineer. They were turnkey projects, each with 156 units.
Earlier the Authority did the 50-unit Franklin Tower, 150-unit Kennedy Towers, and has underway the 70-unit Samuel G. Hubert. Nearby the Episcopal Church is building its 15-story Episcopal House with 4x8x8 loadbearing through-the-wall clay masonry which provides a finished wall on the exterior and the interior. Involved are architects Muhlenberg, Green & Veres; structural engineers Long & Tann; mason contractor Leroy Renninger (MCAA), and general contractor Thomas Armbruster.
Isabella House in New York City, designed by Weiss Whelan Edelbaum Webster, offers a new adventure in living for the elderly.
Convenient Medical Facilities
In New York City, Isabella House is described by its owner as "a new adventure in living for older people." The owner, Isabella, is a non-profit organization founded in 1875 to care for aged persons of German descent. It now has a wide range of services including the 17-story Isabella House. Its occupants live in comfort and security in furnished apartments with $115 to $186 a month rents.
The Waldom Contracting Co., worked in conjunction with the general contractor, Walsh Construction Co., in creating the highrise. Structural engineer was Wilcox & Erickson.
Isabella's Frederick P. Riedel feels "... the private sector of our economy and the public sector need to work together cooperatively to help effectively solve the many social problems of the day." In this case, the cooperation was achieved (Continued on page 26)