Engineering Commons^™

An Investigation On The Effects Of Cellulose Nanofibrils On The Performance Of Cement Based Composites, Hosain Haddad Kolour

Electronic Theses and Dissertations

Cellulose nanofibrils (CNFs) are hydrophilic biodegradable nanoparticles (typically, less than 0.2 mm in length and 20-50 nm in width) that can be extracted from various plants, trees, and recycled paper stock. Their low density, low toxicity, relatively low cost, high aspect ratio, and high specific surface enable functionalization. In this work, the effects of CNFs on selected properties of cement paste, mortar, and concrete were investigated. For the cement pastes, rheology tests using a simple rheometer showed a reduction in workability as CNF dosage increased. Free shrinkage tests showed an increase in shrinkage at high w/c ratios but a decrease …

Feasibility Of Hybrid Thermoplastic Composite-Concrete Load Bearing System, Camerin M. Seigars

Electronic Theses and Dissertations

Thermoplastic composites have many advantages over thermoset composites such as being recyclable, rapidly manufacturable, and more impact resistant. The goal of this thesis is to assess the feasibility of using thermoplastic composites in structural applications through literature review, mechanical testing, design of a load-bearing hybrid composite-concrete structures, and the implementation of thermoplastic composites for tensile reinforcement of concrete. The study had four objectives covering the stated goal.

1. Conduct a literature review to direct thermoplastic material selection
2. Characterize thermoplastic material mechanical properties using standardized mechanical testing
3. Design a hybrid composite-reinforced concrete beam, and
4. Develop thermoplastic shear connectors to develop composite action …

The Confinement Effects On The Fiber Pullout Response Of Ultra-High Performance Concrete (Uhpc, Arden Mcswain

Honors College

Fiber pullout tests were conducted on more than ninety 10 mm by 10 mm cylindrical concrete specimens with a single, straight steel fiber embedded 10 mm in the center of the concrete specimen. Each specimen was subjected to one of three levels (90 N, 2000 N, 4000 N) of confining force applied by a steel fixture and a servo-hydraulic Instron test frame was used to conduct fiber pullout tests. A previously published fiber pullout model was used to determine the approximate bond strength and frictional stress experienced by the fiber-concrete matrix for each of the three confinement levels. Results show …