Masonry Magazine June 1964 Page. 11
Problems
In Specifying
Mortars
By Edwin T. Pairo
Mr. Pairo is Specifications Chief. Chatelain, Gauger and Nolan, Architects and Engineers, Washington, D. C. He is immediate Past President of the Construction Specifications Institute. This paper was presented by Mr. Pairo at the Building Research Institute's Conference on Quality Control of Mortars, held as part of the BRI 1963 Fall Conferences, November 19-21, Washington, D. C.
Here is a stimulating article excellently written on a subject of great interest to every mason contractor. Take a few minutes and read this presentation.
As I look over the panel for today's seminar, I see a particular section of the construction industry represented - notably scientists, scholars, technicians, research people, and others of that special realm of research and development in industry. While many people not actively engaged in specifications writing may regard my vocation as chiefly a function of the drafting room, let me assure you from my years of experience that the specifications writer is not only continually engaged in applied research, but also that contact with basic research is not unknown to him. Therefore, I can talk to you as one who understands and appreciates the contribution that you are making to the advancement of the science of construction.
As has been indicated to you, I enjoy the position of immediate past president of the Construction Specifications Institute, an organization created for the prime purpose of improving construction specifications. I do not appear today as an official representative of that organization, but rather as an individual specifications writer. As such, I can speak freely to you on today's subject.
As you realize, there are two principal parts to construction documents: 1 the plans, be they architectural or engineering; and 2 the specifications. The realm of specifications covers many facets: specifications for building construction; specifications for heavy engineering projects such as dams, roadways, power plants. sewage treatment plant, and water works, to name but a few; maintenance work, for which millions of dollars are spent annually; landscape work; and all phases of manufacturing-aircraft, automobiles, furniture, accessories, etc.
Let us examine just one of these facets-building construction. In any building construction, whether it be residential, commercial, churches, schools-large or small-specifications are involved. Specifications for residences may have from 10 to 12 sections; commercial buildings may have 22 to 30 sections; and monumental buildings sometimes need from 40 to 50 sections. But large or small, one section invariably appears in any specification-"Masonry Work," which, of courses, includes masonry materials and mortars. This brings us to the subject of today's meeting. "Problems in Specifying Mortars."
With respect to masonry mortars, there are many items on which more definite information is needed, and needed particularly in non-scientific language, so that it may become a working tool of the specifications writer. It is the specifications writer who must reduce all aspects of construction materials to clear, concise, and complete delineation of what is to be used, and quality of the work and, in many cases, where the materials are to be used, when such information is not readily incorporated on the drawings. Masonry mortar and its uses fall into the later category.
As a general rule the type, size and kind of masonry units and the overall design of walls are established by the architectural designers well in advance of development of details and preparation of specifications. The color of mortar may be similarly preselected. In most cases, masonry units are selected on the basis of achieving maximum aesthetic results without too much concern with the methods of attaining maximum wall integrity. It remains for the detailer and specifications writer to come up with solutions to all the problems involved, both with respect to requirements for accessory materials and for control of construction work in the field.
Mortar is an accessory material. Its sole function is to hold masonry units apart and to bond them together to form, for all practical purposes, a homogeneous watertight structure. But the performance of masonry depends almost altogether on how well this accessory-mortar does it job, and the class of workmanship going into construction of the assembly. In these respects, mortar is as important as reinforcing steel in concrete, fasteners in structural framing, or felts in built-up roofing. But the selection of the proper mortar for the specific job involved is far from being as simple as the selection of suitable reinforcing steel, structural steel fasteners, or roofing felts.
So much of the information available from mortar material manufacturers and from other authorities is contradictory. Manufacturers of proprietary masonry cements