I guess we should share that with the fence / railing manufacturers and installers that have millions (ten's of millions?) of aluminum fence posts set in concrete?
How does an industry that is cosmetic and driven by cost have to do with a handrail that someones life can depend on. The fencing industry also imbeds wood post in concrete and continues to do so at of ease of construction even though its bad to the longivity of the fence.
Quoted from ACI 222.3R-11.
"3.5.2 Aluminum—Aluminum reacts with alkali hydroxides in portland cement paste, resulting in the liberation of hydrogen gas and alteration of the aluminum to various hydrous aluminum oxides (Monfore and Ost 1965). When aluminum powder is added to portland cement paste, the formation of hydrogen gas can be used to make highly air-entrained (cellular) concrete or mortar, or expansive grouts when used in lesser amounts. In each instance, the desired property is attained when the concrete or mortar is plastic. Because fine aluminum powder reacts completely when the concrete or mortar is plastic, no subsequent volume change occurs after hardening, unlike the continued corrosion of residual aluminum. Aluminum in solid forms, such as conduit, sheets, or rods, chemically reacts similar to finely powdered aluminum, but at a slower rate due to a lower surface area. The reactions initially generate hydrogen gas, and sometimes small bubbles remain on the aluminum surface. These voids are inconsequential; however, reactions occurring after the concrete hardens result in the formation of hydrous aluminum oxides, such as gibbsite, boehmite, and bayerite, with an attendant in-place volume increase. Significant corrosion of solid aluminum products can produce two important phenomena: • Reduction of the aluminum cross section—the corrosion can be sufficiently extensive to completely corrode conduit or pipe walls; and • Increase of the volume of the corrosion products— sufficient stress can cause the encasing concrete to rupture. A similar phenomenon is responsible for concrete cracking due to corrosion of aluminum posts and balusters (Wright 1955) inserted in concrete and due to aluminum window frames in contact with concrete. The reported number of cases involving corrosion of aluminum (Copenhagen and Costello 1970; McGeary 1966; ENR 1964; Wright 1955; Wright and Jenkins 1963) is large enough to caution against using aluminum in or in contact with concrete, unless the aluminum is properly coated using certain plastics, lacquers, or bituminous compounds (Monfore and Ost 1965). Anodizing gives no protection (Lea 1971). The addition of calcium nitrite was also found to improve the corrosion resistance of aluminum in contact"
I will trust the concrete industry says over what fencing contractors say/do.
metalcreteindustries.com
