Aspects and optimization of the mixture for high performance concrete

¹ Faculty of Civil Engineering, Department of Building Materials and Diagnostics of Structures, VSB - Technical University of Ostrava, Ludvíka Podéště 1875/17, 708 00 Ostrava-Poruba, Czech Republic.
² STAVBY VANTO, s.r.o., nam. Svobody 362, 6804 Kunovice, Czech Republic

^* Corresponding author: jan.jerabek@vsb.cz

Abstract

High-performance concrete is currently receiving a lot of attention in research due to its properties and wide range of uses. This paper is focused on HPC, where the optimization of the mixture is specifically addressed regarding the technological solution of construction. The first reference variant uses an approach that is suitable for processing at a concrete plant. An alternative solution is intended for the processing of dry concrete mixture, which can be bagged and the concrete itself produced at the construction site. The paper deals with the comparison of two HPC based on the same input and quantity of raw materials except for the superplasticizer. The purpose is to determine the HPC behaviour and properties of a reference mixture with conventional liquid superplasticizers and a mixture using powdered superplasticizer. The experimental program includes tests of the mechanical properties of compressive strength and flexural strength, where growth was monitored during the first 28 days, split tensile strength and velocity of ultrasound wave. Attention is also paid to fresh mixture tests. Although in the long term the mechanical properties of tested materials were very similar, the difference was determined during the first few days and weeks of hardening, when in mixture using powdered superplasticizer strength characteristics were increasing noticeably slower than in case of referential mixture.