| Summary: | Recent years, method of concrete strengthening has been a rising issue. In structure
of concrete or concrete repairing works, the most Important element is that the bonding
itself. The surface preparation of concrete substrate will give differ results in term of
bonding behavior. Performance of a structural system such beams and slabs are relies on
behavior of the bonding between the old and new concrete. The research intended at
studying the bonding strength between the old and new foamed concrete due to surface
preparations. Factors such as roughness of surface, compaction, and concrete curing affect
the bond. In this study, the surface of the old concrete were partially chipped using a light
jackhammers and differed in terms of its numbers. The research was also to observe failure
mode pattern due to different number of chippings. Samples were tested for two different
methods namely Splitting Test and Slant Shear Test. The slant shear tests were conducted
to investigate the bonding strength in term of shear. For slant shear test, 12 blocks sizing
100 mm x 100 mm x 400 mm were prepared. Meanwhile, the slant shear test was
conducted to measure the axial tensile strength of a concrete submitted to compression
along its length. For this test, 12 cube specimens ofize 150 mm x 150 mm x 150 mm were
prepared. These tests were conducted on 28 days after standard air curing because at day 28
the concrete had fully achieved its true strength. Foamed concrete was used to reduce the
self-weight of the structural element compared to the conventional concrete. For each
testing method, three samples were prepared and differed in term of surface roughness of 0,
10, 20 and 30 number of drill holes. From the results, S30 for Splitting test and SR30 Slant
shear test showed the highest in terms of bonding strength compared to lower surface
roughness with values of 2.17 N/mni2 and 21.73 N/mrn2 respectively. However,
all
types
of surface roughness are failed intermof bonding.
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