Effects of crystallized capillary impermeability admixtures on mechanical and durability properties of concrete and mortar

Concrete is the most used building material today. It has many advantages as well as disadvantages. One of the most important disadvantages is that concrete has a permeable structure. Good concrete must be durable. The condition of durability is that the concrete is impermeable. The permeability of concrete is related to its porous structure. The small void makes the concrete impermeable. Harmful substances such as sulfate and chloride are transported with water to the concrete. These substances damage the concrete over time and shorten its service life of the concrete. Today, many studies are carried out to reduce the permeability of concrete. In these studies, the concrete has been studied to have the minimum permeability by using mineral and chemical additives. Thus, it is aimed to increase the service life by minimizing the permeability of the concrete. In this thesis, the effects of concrete admixtures providing capillary impermeability on the mechanical and durability properties of concrete and mortars were investigated. The purpose of the experiment is to determine how effective the additives are against impermeability and strength. Experiment started by preparing samples by adding different admixture ratios to CEM-I 42.5R Portland cement. The flexural and compressive strengths of the samples, which were kept in water for 28 days by adding 1% and 2% liquid and powder additives, were measured. Scanning Electron Microscopy (SEM), X-Ray Diffraction Analysis (XRD), and Thermogravimetric Analysis (TGA) analyses were performed to determine the microstructural characterizations of the specimens after the resistance tests. Analysis and test results showed that the addition of crystalline admixture increased the compressive strength but did not affect the flexural strength. However, the analysis results showed that both liquid admixtures and powder admixtures play an important role in durability as they support crystal formation, fill the voids, and increase impermeability.