The major environmental impact of concrete comes from the CO₂ emissions, produced during the cement manufacturing process. The main goal of this research project is to evaluate the efficiency of limestone powder as a partial cement replacement, in order to reduce energy consumption and CO₂ emissions. This study utilizes limestone powders, with different particle sizes, to replace a portion of Portland cement using various ratios. Due to the dilution effect when partially replacing cement, there is a reduction in the concrete’s physical properties. To assess the dilution effect, a modification to Féret’s equation is used to calculate an efficiency factor for the limestone powder when compared to cement. To measure the environmental impact, a life cycle assessment is conducted on concrete made with limestone powder combined with cement. This allows for an evaluation of the various cement/limestone powder ratios that will maximize the environmental benefit, with minimal reduction in concrete strength. Additional microstructural analysis using petrographic examination was completed to provide a visual understanding of the distribution of the limestone particles within the cement paste. The results indicate that the efficiency of limestone powder in partially replacing cement can be achieved by particle packing and particle distribution in the concrete and the benefits of emission reductions exceed the loss in compressive strength when higher levels of limestone powder is used to replace cement.

The objective of this study was to carry out a mixed methods construction education study seeking to improve student learning. This study uses project-based learning (PrBL) and milestone deliverable pedagogy to teach a concrete industry project management course and compares the outcome to a control (non-PrBL) version of the same course. The intervention course was designed as a full semester learning experience for students. The students worked as project managers from start to finish constantly contributing to the completion of their team project. In the control scenario, delivered in Fall 2013, students were required to carry-out a traditional project due at the end of the semester. This study examines the impact of having the course project become the main learning mechanism and considers and measures the ways in which PrBL affects student performance. Pre and post questionnaires regarding self-perceptions of learning and skill development were administered and project and course grades were used to assess the impact of PrBL on the students’ performance. The questionnaires revealed a minimum increase of students’ perception of their understanding of 48%. The course grade comparison showed an average of 13% point increase in all student grades when the PrBL pedagogy was implemented.

The development of non-proprietary Ultra-High Performance Concrete (UHPC) is one way to reduce the initial cost of construction. However, workability is a major issue for which such mixtures are not practical in field conditions. Ultra-high performance cannot be achieved in field conditions if the concrete is not placed, finished, and compacted properly during placement. In this research, six UHPC mixtures were developed (three with steel fibers and three without fibers) using materials which are readily available on the local marketplace with water-to-cementitious materials ratios ranging between 0.17 to 0.30. The workability was determined using standard ASTM flow table apparatus, and specimens were prepared to determine compressive strength, splitting tensile strength, and permeable porosity. Flow table test exhibited flow values greater than 250 mm. Such high workability of the mixtures was achieved by optimizing the silica fume content and water reducing admixture dosage. These mixtures exhibited compressive strengths greater than 120 MPa and splitting tensile strengths greater than 5.10 MPa in both ambient and elevated curing temperatures. Results indicated that UHPC can be produced with a water-to-cementitious materials ratio as high as 0.30. Steel fibers helped to increase splitting tensile strength due to fiber-matrix interactions. Very low permeable porosity (1.7–16.7%) was observed which indicates superior durability due to the significant reduction of ingress of deleterious ions.