![]() Select the optimum asphalt binder content.Determine the density and other volumetric properties of the samples.Passing values of stability and flow depend upon the mix class being evaluated. This testing machine is specific to the Marshall mix design method. Test the samples in the Marshall testing machine (see Figure 2) for stability and flow.This hammer is specific to the Marshall mix design method. Compact these trial mixes using the Marshall drop hammer (see Figure 1).There should be at least two samples above and two below the estimated optimum asphalt content. For instance, two to three samples each might be made at 4.5, 5.0, 5.5, 6.0 and 6.5 percent asphalt by dry weight for a total of 10 to 15 samples. Prepare a series of initial samples, each at a different asphalt binder content.In the Marshall method, this step can be broken up into 5 substeps: Optimum asphalt binder content determination.Often, aggregate from more than one source is required to meet gradation requirements. ![]() For each mix design, gradation and size requirements are checked. Private labs may or may not run periodic aggregate physical tests on a particular aggregate source. Different agencies/owners specify different methods of aggregate acceptance. Typically, the Marshall mix design method consists of three basic steps: The Marshall method is very popular because of its relative simplicity, economical equipment and proven record. The basic concepts of the Marshall mix design method were originally developed by Bruce Marshall of the Mississippi Highway Department around 1939 and then refined by the U.S. This section briefly discusses the Marshall mix design method. Like the Hveem and Superpave methods, the Marshall method has been proven to produce quality HMA from which long-lasting pavements can be constructed. Most private laboratories use the Marshall method because it is a proven method and requires relatively light, portable and inexpensive equipment.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |