AASHTO R 75-16 pdf free download

AASHTO R 75-16 pdf free download.Developing a Family of Curves.
1. SCOPE
1.1. This standard practice provides a process for dcvctoping a family of curves usrng multiple individual moisturcdensty relationships (curves) developed according to T 99 or T I go.
1.2. The values stated in SI units arc to bc regarded as the standard.
2. – REFERENCED DOCUMENTS
2.1. AISIITO S1uncIards
• T 99, Moisture-Density Relations of’ Soils Using a 2.5-kg (5.5-tb) Rammer and a 305-mm
(12-in.) Drop
• T 180. Moisture-Density Relations of Soils Using a 4.54-kg (l0-lb) Rammer and a 457-mm
(18-in.) Drop
3. TERMINOLOGY
3.1. DefIniiion.c:
3.1.1. /an,th ol curves—a group 01 soil moisture-density relationships (curves) determined using I 99 or T 180, which reveal certain similaritics and trends characteristic of the soil type and source.
3.1.2. spine—-smooih line extending through the point olmaximum dcnsity’optimum moisture content of a family of moisture-density curvcs.
4. SIGNIFICANCE AND USE
4.1. All curves used in a family must be developed using a single Method: A, B. C, or D of T 99 or T 180.
4.2. Curves arc plotted on a graph: the family is developed by drawing a smooth line through the maximum density optimum moisture points. Al least three curves arc required to form a single lam ii y.
4.3. Gencrally, it will be found that higher unit mass soils assume steeper slopes with maximum dry densities at lower optimum moisture contents, while the lower unit mass soils assume flatter, nKwe gently sloped curves with higher optimum moisture contents (Figure 1).
5. DEVELOPING A MOISTURE-DENSITY FAMILY OF CURVES
5.1. Sort the curves by Method (A. B, C, or D of T 99 or T IXO). At least three curves arc required per family.
5.2. Select the highest and lowest maximum dry densities from those selected to assist in determining thc dcircd scale of the subsequent graph.
5.3. Plot the maximum density and optimum moisture points of the selected curves on the graph.
5.4. Draw a smooth, “best fit,” curved line through the points creating the spine of the family of curves (Figure I).
5.5. Remove maxinium density and optimum moisture points that were not used to establish the spine.
5.6. Add the moisturedensity curves associated with the points that were used to establish the spine. It is not necessary to include the portion of the curves over optimum moisture.
Note I —Intermediate template curves using slopes similar to those of the original moisture- density curves may be included when maximum density points are more than 2.0 Ih& apart. Template curves are indicated by a dashed line. 5.7. Plol the 80 percent otoiJurnum moisture range when desired: 5.7.1. Using the optimum moisture of an existing curve, calculate X0 percent o optimum flKNSIUFC and plot this ‘alue on the curve. Repeat for each curve in the family. 5.7.2. Draw a smooth, ‘tbest Iit,’ curved Irne connecting the KO percent of optimum moisture points plotted on the curves that parallel the spine. 6. KEYWORDS 6.1. Family of curves: rmisturedensity relationships.AASHTO R 75-16 pdf download.