Objectives:
The main objective of this WP is experimental testing of hardened concrete samples reinforced with basalt-boron fibers to investigate the most important material parameters. The material properties will be determined based on compressive strength tests, tensile strength tests, three-point bending tests etc. To fulfill the objective of this WP fresh concrete mixes with various doses of basalt-boron fibers of two different types of boron-basalt fibers added will be prepared.
Expected results and deliverables:
- Performance parameters for of the influence of basalt-boron additives the hardened concrete established.
Current status:
The mechanical properties of fresh concrete were studied using a shrinkage and shrinkage test, and the presence of air in the concrete mix (porosity). The mechanical properties of hardened concrete were also investigated using tests for compressive strength, tensile strength, shrinkage and tensile strength at three points.
After analyzing the results of tests in hardened concrete, we can conclude that the addition of BBF to heavy concrete leads to a slight loss of water, so it is necessary to change the composition of concrete by adding more water or a certain type of plasticizer. The test results showed that BBBF-7 and BBBF-10 show the best mechanical properties. With decreasing or increasing the dosage of basalt-boron fiber, the mechanical properties of concrete deteriorate.
Experiments with neutron source revealed that addition of BBF as a dispersed concrete reinforcement could improve the neutron radiation shielding of plain concrete by up to 25%. On the basis of mechanical tests, it turned out that compressive strength, tensile splitting strength and flexural of concrete reinforced with BBF were lower by up to 15% than analogous values for plain concrete. Simultaneously, shrinkage strain of BBF concrete was lower by about 10% than of plain concrete. Fracture process zone development on the surface of samples was investigated by Digital Image Correlation (DIC) using camera with the 36 megapixel matrix that allowed to obtain pixel size of 18 mm resulting in the length resolution equal approximately 60 pixel/mm Experiments revealed that basalt fibers infused with boron oxide as a concrete dispersed reinforcement improved the ability of limiting microcracking area and bridging macro-cracking by up to 28%.
There are some photos of above tests on Figures .
