Please use this identifier to cite or link to this item:
|Title:||Potential applications of alkali-activated alumino-silicate binders in military operations|
|Authors:||United States. Assistant Secretary of the Army (R & D)|
Malone, P. G.
Randall, Charlie A.
|Publisher:||Geotechnical Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||Miscellaneous paper (U.S. Army Engineer Waterways Experiment Station) ; GL-85-15.|
Abstract: A preliminary study was undertaken to evaluate the potential applications of alkali-activated alumino-silicate binders in military operations. Alkali-activated binders are produced by mixing a concentrated alkali-solution (such as potassium or sodium hydroxide) with a fine-grained, non-crystalline alumino-silicate (such as granulated slag or fired clay). The resulting reaction is reported to produce a series of calcium hydrosilicates (tobermorites) and mixed calcium sodium aluminum silicates (zeolites) and hydrogarnets. The hardened binder shows exceptionally strong bonding to aggregate and the binder/aggregate mixes have been reported to show as much as 27 MPa or 4,000 psi unconfined compressive strength in four hours. Strengths as high as 175 MPa or 25,000 psi can be developed in 28 days. Heats of reaction are very low and external heating is usually needed to insure rapid curing. Alkali-activated binders usually have low water content, high density and low permeability. Sulfate resistance is high and the binder does not accelerate corrosion of reinforcing steel. An alumino-silicate binder that can be cured to develop high early strength and good bonding characteristics may be adaptable to Army repair and construction needs. Major areas that are identified as requiring special construction materials are repair of lines of communication including repair and restoration of paved surfaces such as roadways, runways and bridge decking and the construction of roads and airfields. Rapid-setting high-strength binders could also be employed in movement of military traffic over beaches and soft soil. Alkali-activated binders have a number of properties that make them potentially useful for expedient construction and repair. Raw materials are stable in storage and can be used with substandard aggregate without loss of strength. A minimum of make-up water is required and water quality is relatively unimportant (salt water can be used if necessary). Bonding to materials other than asphalt is excellent. Alkali-activated binders have low toxicity and require no organic solvents for mixing or clean-up. Most equipment used to handle portland cement concrete can be made to operate with alkali-activated binders. Heat curing allows the binder to be placed under adverse conditions. A small-scale pavement patching demonstration using a commercially developed alkali-activated binder showed that a 1.62 x 1.62 m pavement patch (18-cm-thick) could be placed and cured in four hours and would develop sufficient strength to carry a 12.2 metric ton load on a F4 fighter wheel.
|Rights:||Approved for public release; distribution is unlimited.|
|Appears in Collections:||Miscellaneous Paper|