Effect of interfacial transition zone on the Young's modulus of carbon nanofiber reinforced cement concrete

Journal Article · Tue May 15 04:00:00 EDT 2018 · Cement and Concrete Research

DOI:https://doi.org/10.1016/J.CEMCONRES.2018.02.014· OSTI ID:22806482

Zhu, Xingyi ^[1]; Gao, Yuan ^[2]; Dai, Ziwei ^[1]; Corr, David J.; Shah, Surendra P. ^[2]

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1. Key Laboratory of Road and Traffic Engineering of Ministry of Education, Tongji University, Shanghai 200092 (China)
2. Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL 60208 (United States)

Identifying the properties of the region where the cement paste meets the aggregate surface (interfacial transition zone, ITZ) is critical to understanding the strength and fracture behavior of carbon nanofiber (CNF) reinforced cement concrete. In this study, the finite element method is employed to investigate the effect of the ITZ on the Young's modulus of cement concrete made with CNF. The numerical models for cement concrete with and without CNF are constructed based on the digital image processing technique. To consider the interface effect, the concept of ''effective aggregate'' is put forward, namely, the Young's modulus and Poisson's ratio for each aggregate particle are replaced by an effective Young's modulus and effective Poisson's ratio, in which the effect of thickness and the Young's modulus of ITZ is taken into account in an averaged manner. Then, the quantitative nanomechanical mapping (based on atomic force microscopy) technique is adopted to measure the Young's modulus and thickness of ITZ with and without CNFs, which are further used as the input parameters in the numerical model. The numerical simulation results are verified by experimental testing, which indicates that the ITZ effect should be considered when implementing the numerical simulation. In addition, this analysis shows that compared with the plain cement concrete, CNFs can greatly enhance the mechanical properties of ITZ, which will in turn improve the Young's modulus of cement concrete significantly. Finally, the effect of thickness and Young's modulus of ITZ on the Young's modulus of CNF reinforced cement concrete is also discussed.

• OSTI ID: 22806482
• Journal Information: Cement and Concrete Research, Journal Name: Cement and Concrete Research Vol. 107; ISSN 0008-8846; ISSN CCNRAI
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
ATOMIC FORCE MICROSCOPY
CARBON FIBERS
CEMENTS
COMPUTERIZED SIMULATION
CONCRETES
FINITE ELEMENT METHOD
FRACTURES
IMAGE PROCESSING
MECHANICAL TESTS
NANOFIBERS
POISSON RATIO
SURFACES
THICKNESS
YOUNG MODULUS