Concrete Construction published articles in August and September about a new linseed oil emulsion for concrete curing and antispalling protection, but we hear that linseed oil use is being discontinued. How can this be?
Linseed oil, like concrete and steel, can take a variety of forms. At least four kinds of commercial products are offered for use on concrete. One product, linseed oil emulsion, described in Concrete Construction was developed in 10 years of research by the United States Department of Agriculture's Northern Marketing and Nutrition Research Laboratory at Peoria. The USDA emulsion for single application as a curing and antispalling agent--linseed double agent on concrete--was patented in 1966. Another kind of product includes other emulsions made for a specific order, a specific job or to meet a bid specification. Emulsions are simply mixtures of oil in water with other materials--emulsifiers, soaps, detergents--to make them mix. Unless a formula is defined and followed carefully, the emulsion is not defined and will vary. It will be better some times than others. A third kind includes solutions of the oil in solvents like kerosene, mineral spirits, turpentine or even gasoline. These solutions, sometimes called cutback, have been applied to cured concrete to reduce spalling or scaling. Some people say concrete does not need antispalling protection and have discontinued using solutions. These may be what you have heard about. In some of these areas, however, more elaborate efforts to stop spalling or to repair the concrete are being tried. The fourth kind of product we know about is a chemically modified linseed oil. The National Flaxseed Processors Association has more information on it.