Investigation of the Mechanical Properties of Ultra High Performance Concrete Unarmed and Armed with Steel fibers, Polypropylene and Polyvinyl alcohol

Concrete as the most consuming material Construction has long been a response to the growing needs of the human community, whose parameters are constantly changing. Scientists' research over the past two decades has led to the emergence of a new type of concrete with high properties and high compressive strength, which is known as concrete with ultra high performance. The main goal of the present study is to achieve a mixing design with a compressive strength suitable for ultra high performance concrete, without the use of fibers. First, the basic mixing plan has been considered, and with the change in the type and size of materials and also by applying different curing, the compressive strength of the samples has reached 212 MPa. To create ductility and absorption of energy in concrete made with mixing design The present research has used polyvinyl alcohol fibers, polypropylene fibers and steel fibers as a single and hybrid for the reinforcement of concrete. Maximum usable fibers, ductility, and compressive strength that make the fibers mentioned Single and hybrid for this concrete are determined and compared with each other. The results of this experimental study showed that samples containing 2% fiber had the best mechanical performance, as well as samples of 1.5% polypropylene fibers and 0.5% polyvinyl alcohol fibers The most ductility for concrete has been created.