Title: Pedagogical Techniques used to Teach Fresh and Hardened Concrete Properties

Author(s): Kacie C. D’Alessandro, Andrei Ramniceanu, Jacob D. Henschen, Matt O’Reilly

Publication: Symposium Paper

Volume: 359

Issue:

Appears on pages(s): 39-53

Keywords: portland cement, hydration, maturity, microstructure, active learning, in-class demonstrations, concept mapping, inquiry-based learning, daily quiz technology, reinforced concrete pier, strengthening, theoretical model, ultra-high performance concrete

DOI: 10.14359/51740289

Date: 11/1/2023

Abstract:
This paper presents pedagogical techniques used to teach fresh and hardened properties of concrete. Fresh properties of concrete include the evaluation of slump, unit weight, and air content. The hardened properties of concrete include compressive and tensile strengths. Students typically have little to no prior experience working with concrete. Since concrete structures date back to Ancient Rome, many students assume concrete is a basic material that has not changed in centuries, and they do not view concrete as an engineered material. Therefore, their understanding of how concrete is an engineered material and its use is essential. This paper focuses on how both fresh and hardened concrete properties are taught in the classroom to best introduce students to concrete as an engineered material. The pedagogical methods focus on engaging students using experiential education through hands-on laboratory activities, projects, and game-based learning activities. Examples of the pedagogical approaches are presented herein, and they are supported by lessons learned by the authors based on their experience implementing these methods in the classroom. two environmental conditions, sustained elevated temperatures (ST) and freeze-thaw (FT) cycles. The concrete cylinders were wrapped with a single layer of GFRP and CFRP wrap. GFRP wraps improved concrete strength by up to 30% and ductility in excess of 600% for ambient condition specimens, while the enhancements in strength and ductility under the same conditions by CFRP wraps were about 70% and 700%, respectively. The strength enhancements were reduced severely for specimens tested under ST protocol beyond the glass transition temperature (Tg) with a minor reduction in ductility enhancement. On the other hand, freeze-thaw conditioning showed minimal effect on strength and ductility enhancements provided by the FRP wraps. The current and past findings were then used to suggest environmental reduction factors for the design of FRP wraps. A comparison of these factors with ACI 440.2R-17 showed that environmental factors suggested by the ACI code were not applicable at temperatures beyond Tg.