Date of Award

January 2016

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Civil Engineering

First Advisor

Dr. Nabil Suleiman

Abstract

Various types of additives have been applied in the past to Hot Mix Asphalt (HMA) to improve pavement performance. Different techniques including Warm Mix Asphalts (WMA) have helped to increase the workability and strength of pavement as well as decrease greenhouse gas emissions and production costs. Pavement construction can be a challenge in regions with short construction seasons due to various factors including cold weather. It is believed that additives can be a solution for some of those challenges due to lower rate of cooling for such mixes.

This study is carried out to evaluate two hot mix asphalts in the field. One has been modified with the Proprietary additive (creating a non-conventional mix), while the other is kept as a conventional hot mix asphalt with PG 58-28 binder. Asphalt mix field samples for the study were collected from a Cass County, North Dakota project in Summer 2015. Both the conventional and non-conventional specimens were subjected to three different types of tests: rut resistance tests, moisture sensitivity tests, and compaction aid tests.

Six specimens from each conventional and non-conventional mix categories were tested for rut resistance using the Asphalt Pavement Analyzer (APA). The results indicated that the non-conventional mix had higher rut resistance than the conventional mix. Eight specimen from each mix category were tested for moisture sensitivity using the Modified Lottman test under dry and wet conditions. The results showed that the non-conventional mix had higher strength than the conventional mix under both dry and wet conditions. Finally, three specimens from each mix category were compacted at three different temperatures. The air voids of the mixes were compared with the corresponding compaction temperatures. The results suggested that the non-conventional mix had lower air void content, thus better compactibility was achieved than conventional mix. The overall results of the study indicate that Proprietary additive can work as a warm mix additive in North Dakota with favorable performance compared to conventional HMA mixes.

Download

Share

COinS