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The level of energy consumption in renovation activities of buildings has huge advantages
over the demolition of old buildings and the construction of new structures. Such renovation activities
are usually associated with the simultaneous strengthening of their elements, such as externally
bonded carbon fibre reinforced polymer (CFRP) lamellas or sheets on vertical and horizontal surfaces
as structural reinforcements. This means the process of refurbishing a building, as well as the
raw materials themselves have a significant impact on CO2 emissions and energy consumption.
This research paper demonstrates possibilities of replacing state of the art, highly energy-intensive
CFRP lamellas with basalt fibre reinforced plastics as energy-efficient structural reinforcements for
building constructions. The mechanical and thermal properties of basalt fibre reinforced polymer
(BFRP) composites with variable matrix formulations are investigated. The article considers macroand
microstructures of innovative BFRP. The investigations focus on fibre–matrix interactions with
different sizing formulations and their effect on the tensile strength, strain as well as modulus
of elasticity.
Carbon fibre reinforced epoxies (CFRE) are a class of high performance, light-weight composites
that show outstanding, weight-specific (thermo-)mechanical properties. A glassy and
highly cross-linked epoxy matrix provides the composite with a high thermal resistance, but
makes the CFRE also inherently brittle and susceptible to cracks and impacts. One strategy
to overcome this drawback and to improve fracture toughness of epoxy matrices is to modify
the underlying morphology with additional substructures (domains in the nano and/or micron
size range). This allows increasing the energy that is required to initiate or propagate a crack
within the material. The present work contributes to a better understanding of the effect
of substructure-forming, self-assembling block copolymers (BCP) and pre-formed core-shell
rubber particles (CSR) on the toughness and impact behaviour of thin CFREs and their epoxy
matrices. Using a new thermo-optical measurement technique, it is shown that the phaseseparation
process of BCP-rich domains is solely driven by the degree of cure of the epoxy
matrix. Also, it is found that the process of BCP phase-separation, e.g. the BCP-rich domain
size, changes strongly in the presence of carbon fibres. Low concentrations of BCPs (7wt.-%)
yield a 2.5-fold enhancement of the resistance to interlaminar fracture of the CFRE (Mode),
already. Using CSR particles, on the other hand, the energy required to initiate delamination
(Mode II) within the CFRE increases by 160 %. Subsequently, by a hybridization of BCP
and CSR modifiers, after low energy impacts, when both load cases occur in combination, a
synergistic damage volume reduction by more than 67% is achieved. Hence, the generated
material systems and the acquired understanding allow future CFRE based structures to be
even thinner than current design solutions, without affecting their structural integrity under
impact loads.