Abstract: Methods of reducing hydroxyl ions in concrete pore solutions are provided. Such methods are useful in providing resistance to gels which form in concrete due to the alkali-silica (ASR) reaction. The methods comprise adding a salt or mixture thereof to the concrete, in aqueous or solid form, the salt or salt mixture having cations higher in valence than the anions. The methods also comprise adding an acidic phosphate or a silicon-containing alkoxide to the concrete. The methods further comprise resisting and/or inhibiting ASR in airfield runway concrete pore solutions by applying a soluble salt or a mixture of soluble salts in solution or a deicing salt mixture in situ to the runway concrete. All of the above methods are useful in reducing hydroxyl ions in concrete. Such methods can be used to resist ASR in fresh concrete, in concrete that is setting, or in hardened concrete.

Abstract: The present invention relates to a method of immobilizing aqueous waste, including low level nuclear waste, by converting the waste to a solid. Solidification is accomplished with the addition of a compound having the formula Me(II)O or Me(II)(OH)2 in combination with compounds of the general formula Me(II)O.R2O3, R2O3, R(OH)3 or ROOH, where Me is a cation selected from the group consisting of Ca, Ba, Sr, Mn, and Zn, and R is selected from the group consisting of Al, Fe and Cr. Exemplary compounds of the above formula include commercially available calcium aluminate cements, which when added to the waste in combination with a hydroxide of a divalent metal, bind the nitrate ions or nitrite ions in the waste and convert it to a solid.

Abstract: The present invention provides methods for resisting corrosion of metal elements in concrete, and associated compounds and structures. Acid mine drainage sludge is used as a source of a precursor compound that reacts with a source of anion to form a chloride-sequestering compound. The precursor compound may have the formula 2Me?(II)O·(Y(2?x),Y?x)O3+qMe?(II)O, where at least one of Y and Y? is present; Y and Y? are different and are independently selected from the group consisting of Al, Fe, Cr, and not present; Me? is a cation and is selected from the group consisting of Ca, Ba, Sr, Mn, and Zn; x is a number ranging from 0 to 2; and q is a number ranging from 0 to 2; and combinations thereof. In a preferred embodiment, the precursor compound has the formula 2CaO(Fe(2?x),Alx)O3+CaO.

Abstract: A method of resisting corrosion of metal elements in concrete is provided. It includes introducing into concrete containing metal elements, at least one combination compound capable of sequestering chloride ions having the formula 3Me(II)O.(R,R?)2O3.Me(II)(anion)2.nH2O, where R and R? are different and are independently selected from the group consisting of Al, Fe and Cr; anion is selected from the group consisting of NO2, NO3 and OH, n is 0 to 24, and Me(II) is a cation and is selected from the group consisting of Ca, Ba, Sr, Mn, Zn and combinations thereof. In one embodiment of the invention, concrete structures may be rehabilitated by providing an overlay containing the combination compound, with the overlay being provided in situ or as a preformed member and with possible use of a slurry in combination with an overlay segment.

Abstract: In some embodiments, alternate sources of aluminum or calcium are provided in various ways including the desired compounds. The further object of the present invention contemplate in situ creation of the compound in interest in fresh concrete and as a slurry which can be employed in remediation of existing concrete structures. A method of resisting corrosion in concrete containing metal elements is provided. It includes introducing into fresh concrete, containing metal elements, at least one compound capable of sequestering chloride ions. The method may also involve employing a compound which is capable of establishing a corrosion resistant oxide layer on the metal reinforcing elements. The invention also includes certain compounds which may be employed in the method as well as concrete structures containing the compounds.

Abstract: In some embodiments, alternate sources of aluminum or calcium are provided in various ways including the desired compounds. The further object of the present invention contemplate in situ creation of the compound in interest in fresh concrete and as a slurry which can be employed in remediation of existing concrete structures. A method of resisting corrosion in concrete containing metal elements is provided. It includes introducing into fresh concrete, containing metal elements, at least one compound capable of sequestering chloride ions. The method may also involve employing a compound which is capable of establishing a corrosion resistant oxide layer on the metal reinforcing elements. The invention also includes certain compounds which may be employed in the method as well as concrete structures containing the compounds.