Research of different concrete shrinkage reducing strategies effectiveness

Abstract

Concrete and reinforced concrete is one of the most widely used construction material in hydraulic, civil, and transport engineering structures. These structures must have special durability, safety and longevity to avoid various accidents and failures, which have a negative effect to environment. One of the problem causing concrete and reinforced concrete deterioration is shrinkage, which cause internal structural defects and cracking. There are several strategies how to reduce shrinkage in concrete during hardening and to get crack-free concrete. The first strategy is to use special additives and admixtures (expansive, shrinkage reducing, fibres) and the second strategy is to use special concrete curing. Reviewing the scientific works it was not determined which strategy and which materials appling in different strategies is most effective. Therefore, it is important to compare different strategies and materials appling in different strategies for concrete shrinkage reduction. During the research four different materials were used to reduce the shrinkage of concrete (first strategy): expansive admixture (E), shrinkage reducing admixture (SRA), , polypropylene fibres (PPF), monofilament macro synthetic fibres (MMF) and one concrete curing material (P) (second strategy). All research tests were performed according to standard methods. In research were estimated that the best results on shrinkage deformations show shrinkage reducing admixture (SRA), concrete curing material (P) and expansive admixture (E).