Pavement Material Session 07-08 Matakuliah: S0753 – Teknik Jalan Raya Tahun: 2009
Bina Nusantara University 3 Contents Pavement Classification ( material ) Pavement Base course Pavement material and Testing laboratory
Bina Nusantara University 4 Asphalt Asphalt is bitumen. Bitumen is the organic binder, composed of HC with low melting point thermoplastic polymers and oils. Asphalt mix is composite of aggregate and bitumen.
Bina Nusantara University 5 Asphalt Mix The aggregate use as in the concrete that should be clean and angular. Aggregate should have distribution of grain sizes to provide a high packing factor and good mechanical interlock between aggregate grains. AB
Bina Nusantara University 6 Composite and binder Binder is just enough for the aggregate particle to touch, but voids are minimized. Excess binder is weakening asphalt under load due to viscous deformation. When asphalt mix is compress, the binder can squeeze into voids. Too much void space permit water to enter the structure; increase the rate of deterioration of asphalt and may also embrittle the binder
Bina Nusantara University 7 Operation of Asphalt Mix
Bina Nusantara University 8 Operation of Asphalt Mix
Bina Nusantara University 9 Asphalt Mix Problem Asphalt (bitumen) in asphalt mix soften at relative low temperature because it is a thermoplastic polymer.
Bina Nusantara University 10 Base Course Sand Aggregate
Bina Nusantara University 11 Sand Chemically sand = silica (SiO2) Fine minerals The order of 0.1 to 1.0 mm diameter Contain at least some absorbed water Fill voids between the coarser aggregate Giving high packing factor Reducing amount of open (or interconnected) porosity in the finished concrete Reducing disintegration of the concrete due to repeated freezing and thawing during service
Bina Nusantara University 12 Aggregate Gravel & Rock Aggregate must be clean, strong, and durable Angular aggregate particles provide strength due to mechanical interlocking between particles More surface on angular particles may form voids or cracks The large size of aggregate is preferred Aggregate particles should not be larger than about 20% of the thickness of the structure or it will cause the holding defect
Bina Nusantara University 13 Pavement Material & Testing Laboratory
Bina Nusantara University 14 Pavement Material & Testing Laboratory
Bina Nusantara University 15 Pavement Material & Testing Laboratory 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. Army. Currently, the Marshall method is used in some capacity by about 38 states.
Bina Nusantara University 16 Pavement Material & Testing Laboratory Currently, the Marshall method is used in some capacity by about 38 states. The Marshall method seeks to select the asphalt binder content at a desired density that satisfies minimum stability and range of flow values (White, 1985).
Bina Nusantara University 17 Pavement Material & Testing Laboratory This appended test was eventually recommended for adoption by the U.S. Army because: It was designed to stress the entire sample rather than just a portion of it. It facilitated rapid testing with minimal effort. It was compact, light and portable. It produced densities reasonably close to field densities.
Bina Nusantara University 18 Pavement Material & Testing Laboratory The Marshall mix design method consists of 6 basic steps : Aggregate selection. Asphalt binder selection. Sample preparation (including compaction). Stability determination using the Marshall stability and flow test. Density and voids calculations. Optimum asphalt binder content selection.
Bina Nusantara University 19 Pavement Material & Testing Laboratory