Pumice based blended cement concretes exposed to marine environment: Effects of mix composition and curing conditions

Results of an investigation on concrete specimens made with different plain (ASTM Type I, II, and V) and blended cements incorporating different percentages of finely ground pumice up to 30% (as cement replacement) exposed to marine environment for a period of 1 year are presented. Different combinations of mixing water and initial curing conditions simulating cast-in-situ and precast conditions of concreting in marine environment are studied. Blending of Type I and Type II cements with pumice (between 10% and 20%) has shown better resistance against seawater attack than Type V cement with low C3A. The performance of pumice based concrete mixtures is assessed based on the strength reduction criteria and is supported by data from rapid chloride permeability, porosity and differential scanning calorimetry tests. It is recommended that Type I cement with pumice content between 10% and 20% would be a better choice in marine environment. Results also show that the use of precasting instead of casting-in-situ could considerably mitigate the deleterious effect of marine environment on concrete specimens.