Developing Techniques and Gradation Limits
One of the most sought-after concepts in concrete has been a method of proportioning aggregates and paste for a predictable workability. The amount of aggregates in a mixture can drastically impact the workability (Abrams 1918, Powers 1968). If a mixture is too sandy, the workability can drastically decrease and the stiffness of the mixture increase. If the mixture does not have enough sand, the mixture is too “bony” and will not have the plastic and stickiness characteristics need for the placement and finishing for an application (Powers 1938). While the conquest of a proportioning method has created numerous theories to approach this, the popular techniques of proportioning slip formed pavements, which were talked about in Slip Formed Pavements, can be supported by some logical reasoning. However, a limited amount of research has been conducted into these theories and a deeper understanding into the proportioning of aggregates research needs to be conducted.
To take on this task for slip formed pavements, our team created a workability test called the Box Test and a workability performance measurement using WR was also validated. Over 500 mixtures were used to evaluate the popular proportioning techniques of slip formed pavements and develop gradation limits. For more details of this research, please refer to the document below. Also, presentations from the American Concrete Institute (ACI) conference are shown below over the development of the limits.
To take on this task for slip formed pavements, our team created a workability test called the Box Test and a workability performance measurement using WR was also validated. Over 500 mixtures were used to evaluate the popular proportioning techniques of slip formed pavements and develop gradation limits. For more details of this research, please refer to the document below. Also, presentations from the American Concrete Institute (ACI) conference are shown below over the development of the limits.
ODOT OGC Pavement Report.pdf | |
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Spring 2013 ACI Presentation over Coarse Aggregate
Below is a YouTube video of the spring 2013 ACI presentation over optimized graded concrete. This presentation mainly focuses on the Box Test, evaluating different gradation proportioning methods, and developing gradation limits.
Spring 2014 ACI Presentation over Fine Aggregate
Below is a YouTube video of the spring 2014 ACI presentation over the impacts of fine aggregate gradation. This presents the impacts of coarse sand and fine sand on a slip formed pavement mixture.