Sales/Marketing
Quality Assurance
Quality has become one of the most important consumer decision factors in the selecting among competing products and services. This is true not only for individual consumers but also for large corporations, government organizations and the taxpaying public as a group. In its broadest sense, quality is a degree of excellence: the extent to which … Read more
HMA Manufacturing
HMA is produced in a plant that proportions, blends, and heats aggregate and asphalt to produce an HMA that conforming to job mix formula (JMF) requirements. There are two basic types of HMA plants commonly in use today: the batch plant, and the drum plant. Batch plants produce HMA in individual batches while drum plants … Read more
Asphalt
“Asphalt” is a dark brown to black, highly viscous, hydrocarbon produced from petroleum distillation residue. This distillation can occur naturally, resulting in asphalt lakes, or occur in a petroleum refinery using crude oil. In 2001, the U.S. produced almost 35 million tons of asphalt at a rough value of around $6 billion. Roads and highways … Read more
Construction
Construction quality is crucial to the long-term pavement performance. Construction factors such as surface preparation, placement, joint construction and compaction/consolidation have an overwhelming effect on pavement performance, which cannot be ignored or compensated for in mix or structural design. Other construction considerations such as plant operations, mix transport and quality control procedures can also directly … Read more
Materials
Pavements are a conglomeration of materials. These materials, their associated properties, and their interactions determine the properties of the resultant pavement. Thus, a good understanding of these materials, how they are characterized and how they perform, is fundamental to understanding pavement. This section will emphasize what each material is, how it is characterized and the … Read more
Pavement Types
Basically, all hard surfaced pavement types can be categorized into two groups, flexible and rigid. Flexible pavements are those which are surfaced with bituminous (or asphalt) materials. These can be either in the form of pavement surface treatments (such as a bituminous surface treatment (BST) generally found on lower volume roads) or, HMA surface courses … Read more
Superpave Overview
“Superpave” is an overarching term for the results of the asphalt research portion of the 1987 – 1993 Strategic Highway Research Program (SHRP). Superpave consists of (1) an asphalt binder specification, (2) an HMA mix design method and (3) HMA tests and performance prediction models. Each one of these components is referred to by the … Read more
Dowel Bars
Dowel bars are short steel bars that provide a mechanical connection between slabs without restricting horizontal joint movement. They increase load transfer efficiency by allowing the leave slab to assume some of the load before the load is actually over it. This reduces joint deflection and stress in the approach and leave slabs. Dowel bars … Read more
Batch Plant & Mix Design
Batch Plant The asphalt originated from Lakeside Industries’ drum plant (see Figure 1) in Issaquah, WA which is approximately 20 miles from the project site. This counter flow drum plant uses natural gas or diesel fuel to dry/heat the aggregate. The fuel source can be changed as necessary to use the least expensive fuel available. … Read more
HMA Recycling
HMA is one of the most recycled products in the U.S. It is estimated that as much as 91 million tonnes (100 million tons) of HMA are milled off roads during resurfacing and widening projects each year (APA, 2001a[1]). Of this amount, 73 million tonnes (80 million tons) are recycled as “reclaimed asphalt pavement” (RAP … Read more
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