Autogenous self-healing of fibre cements

Jack Harris, Yanjun Zhou, Juliana Calabria-Holley, Kevin Paine

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The University of Bath has developed an innovative fibre cement capable of achieving flexural strengths in excess of 30 MPa. These fibre cements are manufactured by a bespoke method at a low water/cement ratio (less than 0.2). Consequently after hardening there is a considerable quantity of unhydrated cement (a quaternary blend of Portland cement-fly ash-silica fume and limestone) left in the paste. As a result of this it has been considered that after cracking these fibre cements will have significant potential for autogenous healing primarily as a consequence of the hydration of this unhydrated cement and associated pozzolanic reactions. This paper reports on research carried out to test this hypothesis. A number of fibre cements were cast and then cracked after 28 days of curing. The fibre cements were then subject to a number of healing regimes. It was shown that substantial post-crack healing did occur in fibre cements; conventional fibre cements cast at a higher w/c ratio (0.5) were shown not to heal. The precise mechanism of healing was, however, less clear and appears to be due to the leaching of calcium hydroxide and its subsequent carbonation rather than delayed hydration. Reasons for this are discussed in the paper.
LanguageEnglish
Title of host publicationUKIERI Concrete Congress
Subtitle of host publication Concrete: The Global Builder: Working together for durable and sustainable infrastructure
EditorsRavindra K Dhir, S P Singh, Raman Bedi, Sanjay Goel
StatusPublished - 8 Mar 2019
EventUKIERI Concrete Congress, Concrete: The Global Builder: Working together for durable and sustainable infrastructure - Jalandhar, India
Duration: 5 Mar 20198 Mar 2019
https://ukiericoncretecongress.com/ucc2019/

Conference

ConferenceUKIERI Concrete Congress, Concrete: The Global Builder
Abbreviated titleUCC2019
CountryIndia
CityJalandhar
Period5/03/198/03/19
Internet address

Cite this

Harris, J., Zhou, Y., Calabria-Holley, J., & Paine, K. (2019). Autogenous self-healing of fibre cements. In R. K. Dhir, S. P. Singh, R. Bedi, & S. Goel (Eds.), UKIERI Concrete Congress: Concrete: The Global Builder: Working together for durable and sustainable infrastructure

Autogenous self-healing of fibre cements. / Harris, Jack; Zhou, Yanjun; Calabria-Holley, Juliana; Paine, Kevin.

UKIERI Concrete Congress: Concrete: The Global Builder: Working together for durable and sustainable infrastructure. ed. / Ravindra K Dhir; S P Singh; Raman Bedi; Sanjay Goel. 2019.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Harris, J, Zhou, Y, Calabria-Holley, J & Paine, K 2019, Autogenous self-healing of fibre cements. in RK Dhir, SP Singh, R Bedi & S Goel (eds), UKIERI Concrete Congress: Concrete: The Global Builder: Working together for durable and sustainable infrastructure. UKIERI Concrete Congress, Concrete: The Global Builder, Jalandhar, India, 5/03/19.
Harris J, Zhou Y, Calabria-Holley J, Paine K. Autogenous self-healing of fibre cements. In Dhir RK, Singh SP, Bedi R, Goel S, editors, UKIERI Concrete Congress: Concrete: The Global Builder: Working together for durable and sustainable infrastructure. 2019
Harris, Jack ; Zhou, Yanjun ; Calabria-Holley, Juliana ; Paine, Kevin. / Autogenous self-healing of fibre cements. UKIERI Concrete Congress: Concrete: The Global Builder: Working together for durable and sustainable infrastructure. editor / Ravindra K Dhir ; S P Singh ; Raman Bedi ; Sanjay Goel. 2019.
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AB - The University of Bath has developed an innovative fibre cement capable of achieving flexural strengths in excess of 30 MPa. These fibre cements are manufactured by a bespoke method at a low water/cement ratio (less than 0.2). Consequently after hardening there is a considerable quantity of unhydrated cement (a quaternary blend of Portland cement-fly ash-silica fume and limestone) left in the paste. As a result of this it has been considered that after cracking these fibre cements will have significant potential for autogenous healing primarily as a consequence of the hydration of this unhydrated cement and associated pozzolanic reactions. This paper reports on research carried out to test this hypothesis. A number of fibre cements were cast and then cracked after 28 days of curing. The fibre cements were then subject to a number of healing regimes. It was shown that substantial post-crack healing did occur in fibre cements; conventional fibre cements cast at a higher w/c ratio (0.5) were shown not to heal. The precise mechanism of healing was, however, less clear and appears to be due to the leaching of calcium hydroxide and its subsequent carbonation rather than delayed hydration. Reasons for this are discussed in the paper.

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