Collecting data from existing bio ash concrete constructions
DTI will be responsible for this task.
Due to the approval of a Danish National Application Documents to EN206-1, bio ash concrete has been in provisional use in Denmark for concrete for passive environments since 2002. Moreover, bio ash was investigated in the Danish “Green Concrete” project, where part of a highway bridge owned by the Danish Road Directorate was cast with bio ash concrete for aggressive environment.
In co-operation with UNICON who has delivered bio ash concrete over the past few years a list of bio ash concrete structure will be compiled. The list is evaluated based on availability and diversity in concrete type and construction type, and two structures are selected for inspection – one in passive and one in aggressive environment. Already now, two candidate structures are known: i) a highway road cover exposed to ambient conditions since 2002, and ii) an underground sewage construction in connection with waste water detention tanks situated within the AWS catchment area. The inspection of the structures will include visual documentation (photos/videos), macro- and microstructure description (petrographic examination according to TI-B5), as well as documentation of concrete strength from drilled cores.
Progress indicators – 1) Structure for field inspection identified, 2) Field inspections performed.
Expected results - A report with the findings of the field inspections will be issued. In the report, possible correlation between inspection results and concrete composition, casting method, etc., are sought. The report will tentatively compare the field performance of bio ash concrete with that of traditional concrete – the comparison can only be tentative as all existing bio ash concrete structures are still very young. Nevertheless, the analyses performed will provide some indication as the expected long-term performance of bio ash concrete through traditional indicators such as strength and microstructure (e.g. carbonation depth).
Constraints - Even though bio ash concrete has been delivered almost exclusively for use in passive environment it may be difficult to locate a construction in passive environment suitable for inspection. The reason being that concrete for passive environment is often delivered in small quantities, and used in structures that are not readily accessible to inspection, i.e. there is a risk that is will not be possible to locate a structure in passive environment that can be inspected. However, access to the two structures (aggressive environment) already mentioned will be possible for completion of this task.