Title: Applications of Statistical Models for Proportioning Underwater Concrete

Author(s): K. H. Khayat, A. Yahia, and M. Sonebi

Publication: Materials Journal

Volume: 96

Issue: 6

Appears on pages(s): 634-640

Keywords: admixtures; concretes; density; consistency tests; statistical tests; strength; underwater construction (placing); water-reducing agents.

DOI: 10.14359/788

Date: 11/1/1999

Abstract:
A factorial design was carried out to model mathematically the influence of five key parameters on slump consistency, washout mass loss, and compressive strength that are important for the successful development of underwater concrete. The parameters considered in this study were the content of cementitious materials, water-to-cementitious material ratio, (w/cm) sand-to-total aggregate ratio, (s/a) and concentrations of antiwashout admixture and high-range water reducer. The derived statistical models are valid for a wide range of mixture proportioning and reveal the order of influence of each parameter on the modeled responses. The utility of such models to optimize concrete mixtures to achieve good balance between slump consistency, washout resistance, compressive strength, and cost is discussed. Examples highlighting the usefulness of the models are presented using contour diagrams to demonstrate single and coupled effects of mixture parameters on consistency and washout resistance. Cost analysis is carried out to show trade-offs between material cost and specified consistency and washout resistance levels that can be used to identify economic mixtures. The paper establishes the usefulness of the mathematical models as a tool to facilitate the test protocol required to optimize high-performance concrete for underwater applications.