Computer methods in intelligent compaction

The term "intelligent compaction" is now heard often enough to make one believe that the method used for documenting the quality of hot-mix asphalt pavement has evolved to a more modern state than is actually the case. In fact, the current process for determining the density of an asphalt mat uses 1960's technology. The nuclear density gauge was a major break through in the mid-1960's and quickly became the state-of-the-art for measuring asphalt density. It revolutionized the asphalt paving industry because it allowed the owner of the project to check the density of the asphalt mat much more quickly than methods used up to that time. That ability, coupled with improved asphalt production methods led to tremendous increases in constructor productivity. Now, however, the owner rarely checks the density of the asphalt mat during the paving and compaction process. The responsibility for quality control (QC) of the paving and compaction process has largely been given to the contractor. This shift in responsibility comes at a time when the construction industry as a whole is faced with the worst labor shortage in history, limiting the number of qualified QC technicians and equipment operators. Recently, researchers introduced a patented system that, when mounted on a vibratory asphalt compactor, can render an asphalt density reading (in pounds per cubic foot) every one-second in real-time. Details of the system and its successes and limitations have been documented in the literature. This paper briefly describes the system and details the essential contributions made by computer hardware and software to a successful onboard asphalt density measuring system.