Potential Applications of Alkali-Activated Alumino-Silicate Binders in Military Operations

摘要

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 stron 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 ad 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.