Date of Award

Spring 4-24-2015

Document Type

Thesis

Degree Name

Master of Science (MS)

First Advisor

Wil V. Srubar III

Second Advisor

Mija H. Hubler

Third Advisor

Yunping Xi

Abstract

Pervious concrete has been widely used in pavement applications to help alleviate environmental issues related to urban stormwater runoff and pollution. While horizontal infrastructure (e.g., pavements) represent the majority of applications over the past few decades, pervious concrete is now being considered for other building infrastructure applications, such as sound barriers, insulation, and vertical garden walls. These new applications necessitate different physical and mechanical properties (e.g., ultra-high porosities) than pervious pavements. In response to this need, this research defines macroporous pervious concrete (MPC) as a pervious concrete with a minimum porosity of 30% and proposes it as a possible material solution for these new applications. The objective of this work was to characterize the mechanical and physical properties of the MPC under simulated field conditions. Due to the anticipated low strength of ultra-high porosity concrete, the impact of two binder additives, namely sand and titanium dioxide (TiO2), on the compressive strength of MPC was investigated. In addition, the effect of recycled aggregates on the mechanical and physical properties was assessed herein. To compare permeability of MPC to normal (< 30% porosity) pervious concrete, a modified Carman-Kozeny equation was proposed to predict permeability. Results demonstrate that MPC has a lower compressive strength and higher permeability than normal pervious concrete. Additionally, the use of recycled aggregates in lieu of virgin aggregates in MPC does not compromise its mechanical properties, but does impact MPC physical properties. Rather than being controlled by the parameters of unit weight, porosity, and aggregate type that usually govern the mechanical properties of normal pervious concrete, the strength of the MPC binder solely governs its mechanical performance. Furthermore, the data show that cement-binder additions of 7% sand or 2.5% TiO2 improve compressive strengths of recycled-aggregate MPC by 19% and 7%, respectively and that simultaneous use of both additives increase MPC compressive strength by 28%.

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