Basaltic Crushed Rock Stabilized with Cementitious Additives: Compressive Strength and Stiffness, Drying Shrinkage, and Capillary Flow Characteristics

Research was undertaken to increase knowledge of the properties of local stabilized pavement materials to facilitate their wider use in road construction and rehabilitation. Laboratory tests involved testing for the unconfined compressive strength (UCS), shrinkage, and capillary behavior of crushed basaltic rocks stabilized with two conventional cementitious binders—general purpose cement and lime—and two cementitious binders comprising industrial waste products—blended cement and alkali-activated slag. The alkali-activated slag and blended cement significantly increased UCS of untreated material and performed as well as or better than such traditional binders as general purpose cement. Overall, lime performed poorly as a stabilizer of crushed basaltic rocks, primarily because the fine content containing clay minerals was not significant in the crushed basaltic rock composition. UCS of stabilized materials increased significantly as binder content increased; UCS could be described as a function of binder quantity. Ultimate shrinkage increased with binder content for general purpose cement and alkali-activated slag, but for blended cement, behavior was different. The rate of drying shrinkage was relatively high at the early stage of shrinkage. Generally, alkali-activated slag produced less shrinkage compared with general purpose and blended cements. Capillary rise and water absorption were also measured. Test results indicated that the rate of capillary rise and amount of water absorbed by the material matrix decreased with the increase of binder content. The research indicated that the use of binders with industrial by-products could be a viable option in stabilization of crushed basaltic rock materials.