Life cycle design of polypropylene fiber reinforced cement-based composites

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Fiber reinforcement is now used for concrete applications globally to reduce shrinkage and temperature cracking, control crack widths, and provide structural reinforcement. A number of fiber types are used which include metallic fibers, polymeric fibers, and natural fibers. Of the natural fibers, asbestos fibers are used in developing countries due to their low cost and high strength as a reinforcement material in a cementitious matrix. However, asbestos has documented human health impacts which can be severe in developing countries. Polypropylene (PP) is a thermoplastic polymer that has found wide adoption for concrete fiber reinforcement. Its use has been for control of shrinkage and temperature cracking rather than as structural reinforcement of fiber reinforced concrete (FRC) due to its low bond strength in cementitious matrices. The hydrophobic nature of PP leads to low chemical bonding between fibers and the surrounding cementitious matrix. Polarity control through additive copolymerization shows substantive promise in modifying the hydrophobicity of PP to be more hydrophilic. Leveraging this hydrophilic nature, modified PP fibers can be used to structurally reinforce cementitious matrices through formation of a stronger bond with the surrounding cementitious matrix. This thesis presents a novel material design methodology which leverages multi-scale modelling and experimental testing to develop a more sustainable replacement for asbestos fiber cement roofing tiles in developing countries. At micron-scale, single fiber pullout tests are used to determine the chemical and frictional bond strength of untreated and treated PP fibers in a cement matrix. At the millimeter-scale the composite response is analytically modelled to predict bridging stress versus crack width relationships. This response is used to determine the flexural behavior of structural roofing tiles. At the meter-scale (and kilometer-scale of distribution chains), life cycle assessment models are created to quantify the social, environmental, and economic impacts of the new composites. These are used for material composite design at all scales. Ultimately, a polypropylene-based fiber for reinforcing concrete will be created using life cycle assessment as a guiding design tool and with the ability to displace harmful asbestos reinforced concretes in developing countries.


Type of resource text
Form electronic; electronic resource; remote
Extent 1 online resource.
Publication date 2015
Issuance monographic
Language English


Associated with Ali, Subhan Mustafa
Associated with Stanford University, Department of Civil and Environmental Engineering.
Primary advisor Lepech, Michael
Thesis advisor Lepech, Michael
Thesis advisor Billington, Sarah L. (Sarah Longstreth), 1968-
Thesis advisor Deierlein, Gregory G. (Gregory Gerard), 1959-
Advisor Billington, Sarah L. (Sarah Longstreth), 1968-
Advisor Deierlein, Gregory G. (Gregory Gerard), 1959-


Genre Theses

Bibliographic information

Statement of responsibility Subhan Mustafa Ali.
Note Submitted to the Department of Civil and Environmental Engineering.
Thesis Thesis (Ph.D.)--Stanford University, 2015.
Location electronic resource

Access conditions

© 2015 by Subhan Mustafa Ali
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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