Compatibility between base concrete made with different chemical admixtures and surface hardener

Abstract

Many cases of cracking and detachment of the concrete surface have appeared in concrete floors where surface hardeners were used in Portugal. The main causes for cracking and delamination of trowelled concrete pavements are several and it is essential to control bleeding and the time available to perform the finishing operations. Several base concretes were made with different chemical admixtures and one type of surface hardeners. The purpose of this study was evaluating the influence of the “open time” for each chemical admixture. Results show that the type of chemical admixture has a great importance in the control of the “open time” and consequently avoiding cracking and detachment.