TY - JOUR
T1 - Improving bond strength and mass transport properties of spacer-concrete interface with textured spacers
AU - Muslim, F.
AU - Wong, H. S.
AU - Chiu, T. K.Q.
AU - Buenfeld, N. R.
N1 - Funding Information:
F. Muslim gratefully acknowledges the financial support for her PhD study provided by the Indonesian Endowment for Education (LPDP). We thank Mr. Richard Man and Mr. Andrew Morris for their help with the laboratory work including sample preparation and splitting tensile strength testing. The research leading to this publication benefitted from EPSRC funding under grant No. EP/R010161/1 and from support from the UKCRIC Coordination Node, EPSRC grant number EP/R017727/1, which funds UKCRIC’s ongoing coordination.
Publisher Copyright:
© 2021, The Author(s).
PY - 2021/10
Y1 - 2021/10
N2 - Spacers are important devices used in all concrete structures to support reinforcing steel and achieve the required cover. However, spacers induce a weak, porous and microcracked interface that facilitates ingress of aggressive agents. This paper aims to address the problem by developing a method to produce cementitious spacers with a range of small-scale surface textures including grooves, squares, rectangles, hemispheres and pyramids. The textured spacers were cast in Portland cement mortar or concrete, cured up to 28 days, and tested for tensile bond strength, accessible porosity and mass transport properties. The properties were correlated to surface characteristics to establish the effects of texture on spacer-concrete interface. Results show that textured spacers promote mechanical interlocking with concrete, thereby increasing bond strength, resistance against microcracking and pressure-induced flow. The use of certain textures can compensate for the negative effects of spacers, achieving similar bond strength and permeability to monolithic concrete without the interface.
AB - Spacers are important devices used in all concrete structures to support reinforcing steel and achieve the required cover. However, spacers induce a weak, porous and microcracked interface that facilitates ingress of aggressive agents. This paper aims to address the problem by developing a method to produce cementitious spacers with a range of small-scale surface textures including grooves, squares, rectangles, hemispheres and pyramids. The textured spacers were cast in Portland cement mortar or concrete, cured up to 28 days, and tested for tensile bond strength, accessible porosity and mass transport properties. The properties were correlated to surface characteristics to establish the effects of texture on spacer-concrete interface. Results show that textured spacers promote mechanical interlocking with concrete, thereby increasing bond strength, resistance against microcracking and pressure-induced flow. The use of certain textures can compensate for the negative effects of spacers, achieving similar bond strength and permeability to monolithic concrete without the interface.
KW - Bond strength
KW - Durability
KW - Interfacial transition zone
KW - Reinforcement spacer
KW - Surface texture
KW - Transport properties
UR - http://www.scopus.com/inward/record.url?scp=85115193857&partnerID=8YFLogxK
U2 - 10.1617/s11527-021-01782-y
DO - 10.1617/s11527-021-01782-y
M3 - Article
AN - SCOPUS:85115193857
SN - 1359-5997
VL - 54
JO - Materials and Structures/Materiaux et Constructions
JF - Materials and Structures/Materiaux et Constructions
IS - 5
M1 - 191
ER -