01373211

Component

Concrete with partial replacement of cement with metakaolin has the distinct advantage for highway structures providing high visibility due to its white color. Introduction of metakaolin along with reduced water results in increased strength and reduced permeability in concrete. In this investigation, the effects of water content and cement replacement with metakaolin, at various levels, were studied experimentally in two phases. First, the upper limit for cement replacement with metakaolin to achieve reduced permeability was established by maintaining a constant water-to-binder ratio of 0.45. A two-factor factorial design was used to implement analysis of variance (ANOVA) table and obtain an empirical model based on multiple regression analysis. The mixtures were then refined to include the effect of water content. The water-to-binder ratios selected were 0.35, 0.30, and 0.25. For each series of water-to-binder ratios, four levels of cement replacement with metakaolin were selected: 0, 5, 10, and 15%. Two critical aspects of concrete performance were investigated, namely compressive strength and permeability. Using statistical analysis, empirical models were developed to quantify the effects of water and metakaolin content on concrete compressive strength and permeability. Each of these empirical models is expressed as a function of two independent variables: percent replacement of cement with metakaolin, and water-to-binder ratio. The experimental results and statistical analysis performed indicated that contribution of metakaolin to achieve high-performance is more significant than reduced water content. This paper presents the outcome of this comprehensive experimental investigation and statistical analysis.

This paper was sponsored by TRB committee AFN20 Properties of Concrete

01362476

12-1737

English

15p

2012

Transportation Research Board 91st Annual Meeting

Digital/other

Figures; References; Tables

Analysis of variance; Compressive strength; Concrete; Permeability; Regression analysis; Water cement ratio

Metakaolin

Highways; Materials; I32: Concrete

Transportation Research Board Annual Meeting 2012 Paper #12-1737

TRIS, TRB

Feb 8 2012 5:05PM