Crack sealing is considered one of the least expensive and cost effective maintenance activity used on pavements. In some cases, crack sealing suffers from premature failure due to various material, environmental, and construction issues. A survey that was conducted as part of this study showed that the highest sealant failure year occurring on the second year. Therefore, any attempt to increase the sealants’ service life by addressing and improving the sealant properties and their resistance to failure will benefit the effectiveness of this treatment.

The goal behind this study was to evaluate the potential improvement in performance of hot applied sealant material commonly used in the Phoenix area, and evaluate the performance of using a neat binder modified with crumb rubber (at 5 and 10% by weight of binder) as a low-grade sealing material. The sealants was also modified with crumb rubber at 2.5, and 5% by weight fo the sealant. Six ASTM tests were conducted for the comparison. These tests are the Standard Penetration Test (SPT) and Cone Penetration Test (CPT), Resilience Test, Softening Point Test, Brookfield Viscometer Test, and Dynamic Shear Rheometer (DSR).

The results showed that adding only crumb rubber to a neat binder for its potential use as a crack sealant is inadequate to meet the specifications expected for sealants. However, the modification of the sealant with crumb rubber showed some benefits, such as increased elasticity and decreased temperature susceptibility. A crumb rubber content of 2.5% by weight of the sealant was recommended.

As the number of heat waves are expected to increase significantly into the future in the U.S. Southwest, new insight is needed into how urban infrastructure can be repositioned to protect people. In the Phoenix metro area infrastructure have largely been deployed over the past half century, during a time when climate change was not a concern. Now, as the county struggles to protect people from heat, there is a need to reassess how existing and new infrastructure can be positioned to reduce health impacts while improving sustainability. Using a neighborhood in Mesa, Arizona as a case study, we assess how changes to transportation infrastructure, building infrastructure, and landscaping can reduce heat exposure. A number of strategies are considered including the optimal deployment of heat refuges, deploying less convective surface materials, and deploying more thermally preferable building materials. The suite of strategies could be considered by cities throughout the Phoenix metro area.