A company is planning to design and build a structure that must be so free of magnetic effects that ordinary steel reinforcement cannot be used. Are there any nonferrous metals or other materials that can be used as reinforcement?
Following are some materials, including nonmetals that you might investigate: Aluminum. This metal is nonmagnetic. If no calcium chloride will be used in the concrete and moisture is not continually available to support corrosion, there should be no difficulty with aluminum. If such difficulties are anticipated, a coating can be applied to the aluminum. Additional data concerning the use of aluminum as reinforcement could be obtained by contacing Reynolds Metals Company, Project Development Department, Richmond, Virginia 23261. Data from this company indicates that tensile strengths of 72,000 psi can be obtained with aluminum. Monel metal. According to the Mechanical Engineers' Handbook by Marks, Monel metal is feebly magnetic. K Monel is nonmagnetic down to a temperature of -110°F. Tensile strengths of K Monel range from 90,000 to 170,000 psi depending on its treatment in manufacture—hot rolled, cold drawn, or cold drawn and heat treated. Austenitic manganese steel. This is a nonmagnetic alloy containing about 12 percent manganese and 1 percent carbon. When the steel is quenched from a high temperature, a homogeneous austenite is retained and the alloy has the high toughness, strength and ductility characteristics of austenitic steel. Stainless steel. Alloys containing 20 to 30 percent nickel are nonmagnetic. Physical property data on such steel could perhaps be obtained from any steel company or warehouse handling stainless steels. Wood. Bamboo has been extensively used in the orient as reinforcement for concrete. Studies of the use of bamboo as reinforcement are under way at Lehigh University, Bethlehem, Pennsylvania 1 8105. Glass fiber. Glass has high tensile strength. Strands of glass fibers have been used as reinforcement in concrete but the user must be concerned about avoiding alkali attack on the glass (for example by using an alkali-resistant glass or by protecting it from direct contact with the concrete) as well as avoiding fracture from the notch effect of scratches. Pertinent information might be obtained from Owens Corning Fiberglas Corporation, Fiberglas Tower, Toledo, Ohio 43659. A word of caution on nonmagnetic metals is in order, especially Monel metal, austenitic manganese steel and stainless steel. If one of these is to be considered, the physical properties of the specific alloy to be used (for example, the particular Monel metal) should be determined. This is necessary to ensure that creep, fatigue, and other concrete properites will be within usuable limits. It is also necessary to know the yield point and tensile strength of the material to be used.