TY - JOUR
T1 - Influence of supplementary cementitious materials on microstructure and transport properties of spacer-concrete interface
AU - Muslim, F.
AU - Wong, H. S.
AU - Choo, T. H.
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 Hope Construction Materials, Lafarge-Holcim and Elkem for provision of materials. We also thank Mr. Evangelos Pastras, Ms. Xianyi Yu, Mr. Zheng Gu, Mr. Joshua Agbede and Mr. Andrew Morris for their assistance with the laboratory work. 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 Elsevier Ltd
PY - 2021/11
Y1 - 2021/11
N2 - Reinforcement spacers are a critical component of concrete structures. Their presence affects microstructure and transport properties of concrete cover though this is not widely appreciated. This paper presents the first study to determine whether the negative effects of spacers can be mitigated through the use of supplementary cementitious materials such as silica fume, fly ash and blast-furnace slag. Concrete samples (>200) with different spacers, binders, curing and drying regimes were prepared and tested for diffusion, permeation, absorption, electrical conductivity, carbonation and microstructure. It was found that spacers increase all transport properties, the extent depending on type of spacer, drying regime and transport mechanism. The spacer-concrete interface is weak, porous and micro-cracked, and this lowers the resistance of concrete to ingress of aggressive agents. The beneficial effects of SCMs (strength enhancement and densification) and prolonged curing (120-day) are insufficient to overcome the negative effects of spacers. Implications for durability are discussed.
AB - Reinforcement spacers are a critical component of concrete structures. Their presence affects microstructure and transport properties of concrete cover though this is not widely appreciated. This paper presents the first study to determine whether the negative effects of spacers can be mitigated through the use of supplementary cementitious materials such as silica fume, fly ash and blast-furnace slag. Concrete samples (>200) with different spacers, binders, curing and drying regimes were prepared and tested for diffusion, permeation, absorption, electrical conductivity, carbonation and microstructure. It was found that spacers increase all transport properties, the extent depending on type of spacer, drying regime and transport mechanism. The spacer-concrete interface is weak, porous and micro-cracked, and this lowers the resistance of concrete to ingress of aggressive agents. The beneficial effects of SCMs (strength enhancement and densification) and prolonged curing (120-day) are insufficient to overcome the negative effects of spacers. Implications for durability are discussed.
KW - Blended cement (D)
KW - Durability (C)
KW - Interfacial transition zone (B)
KW - Microstructure (B)
KW - Spacers
KW - Transport properties (C)
UR - http://www.scopus.com/inward/record.url?scp=85112803474&partnerID=8YFLogxK
U2 - 10.1016/j.cemconres.2021.106561
DO - 10.1016/j.cemconres.2021.106561
M3 - Article
AN - SCOPUS:85112803474
SN - 0008-8846
VL - 149
JO - Cement and Concrete Research
JF - Cement and Concrete Research
M1 - 106561
ER -