Title: Pumpability of Non-Sand Concrete with Anti-Segregative Additives
Author(s): Felix E. Amparano and Yunping Xi
Publication: Materials Journal
Appears on pages(s): 695-703
Keywords: cement additives; coarse aggregate; concrete
Non-sand concrete is a concrete which only contains normal portland cement, water and coarse aggregate. The use of non-sand concrete has expanded into many areas such as: drainage pipes, wells, small retaining walls, pavements (for local roads and parking lots). One of the disadvantages of such concrete is the difficulty in mixing and placing due to the stiff consistency of the mixture caused by the low water-cement ratio required to prevent segregation. This problem could be much less burdensome, or even eliminated, if methods of placing could be developed using conventional concrete placement methods. The investigation reported in this paper explored one such method, that is, the placement by pumping in which the concrete was made pumpable by adding several admixtures. Pumping characteristics are base on the mixture's ability to provide good slump and excellent cohesiveness. The test results include compressive and flexural strengths, permeability, unit weight, and the potential for the mixture to be pumped successfully. The purpose of this research was to obtain a pumpable non-sand concrete mixture, within the specified design parameters, which does two purposes that is, exhibits excellent pumping characteristics and yields equal or higher strength values than that of mixtures made without admixtures. The results indicated very good performance of mixtures containing silica fume concurrently with the hydroxyethyl cellulose admixture. This holds true for non-sand concrete mixtures containing 12.7 mm and 6.35 mm maximum size aggregates.