A project thesis submitted to the Civil Engineering Program Universiti Teknologi PETRONAS as partial fulfillment of the requirement for An example of permanent deformations is rutting, which is caused by repeated traffic loads that exceed the ability of the pavement structure to maintain its original profile. The particle size distribution or gradation of aggregates is one of the most influential properties in the creep performance analysis.
This report presents the mix design and creep performance data of four grades; gap-graded, continuous-graded, open-graded and dense-graded. The creep performance evaluation is done using the Dynamic Creep Test and the result shows that the dense graded mix gives the best creep resistance. Material deformation occurs as a result of long-term exposure to stress levels that are below the materials yield or ultimate strength.
The rate of this damage is a function of the material properties and the exposure time, exposure temperature and the applied load (stress). An example of a permanent deformation is rutting, which is caused by repetitive traffic loading that exceeds the capacity of the pavement.
PROBLEM STATEMENT
By preparing different bitumen mixtures with different gradations of aggregates; gap graded, continuous graded, open graded and dense graded mixtures.
LITERATURE REVIEW AND THEORY
AGGREGATE GRADATION
Read and Whiteoak (2003) discussed that a continuously graded mixture is one that contains fractions of different (but not necessarily all) sizes throughout the range, while a gapped mixture is one where the sizes are discontinuous. The traditional British standards specifying asphalts have evolved from describing asphalt as gap-graded or continuously gradated. FAE< PROJECTU • DEXEPPA COX . graded materials) while BS 4987 applies to coated macadam (permanently graded.
Dense bituminous macadam gives a surface structure due to the stone content in the material, and compacted may have low. Continuously graded materials include dense bituminous macadam, which is commonly used for road subgrades and supports, and for wearing courses on minor roads.
Lit 'ASA PP. X1KMAYLAX CHEF EEC 4299
AGGREGATE PROPERTIES
- Sieve Analysis Test
The physical and mechanical properties of crushed granite aggregate and oil palm shell (OPS) are shown in Table 3. The physical properties such as specific gravity, water absorption and fineness modulus of sand are listed as 2.56 respectively. As mentioned in chapter 2, the literature review is done to strengthen the knowledge on this topic.
Four tests were conducted which are the Siphon Analysis, Marshall Mix, Marshall Stability Test and Dynamic Creep Test. JKR Standard Specification for Roadworks (continuously graded, refer Table 5 and densely graded, refer Table 7.
JKR Standard Specification for Road Works (continuous graded, refer Table 5 and dense graded, refer Table 7 )
Federal Highway Administration (Open graded, referTable 6)
To determine the gradation of the aggregates
Aggregates (coarse and fine)
Set of sieve
Mechanical sieve shaker
The aggregates are sieved for 5-10 minutes on the mechanical sieve
Aggregates retained on each sieve are weight and percentage passing each sieve is computed
Aggregates proportions are then calculated
- Marshall Mix
UTP Highway Engineering Laboratory Manual
To prepare the bituminous mixture samples
Aggregates (based on specified grading)
Bitumen
Marshall Compactor
Aggregates (which had been oven dried previously) and filler are placed in the mixer and mixed dry about 1 minute. Then, appropriate amount of
The material is then placed in the mould. The material is distributed evenly by tamping the material (using steel rod) 15 times around the
Material is then compacted using Marshall Compactor with 76 blows on
When specimen is cooled down to room temperature it is extruded from the moulds using extruder
- Marshall Stability Test
To determine the optimum binder content that should be used in the
Bathwater
Marshall Stability equipment
Sample is weighed in air and in water using the Buoyancy Balance Test
Then, sample is placed in the Marshall Stability testing machine and
Results arethen analysed to determine the optimum binder content
- Dynamic Creep Test
Universal Testing Machine manual
British DD226 test setup
To determine the creep performance of bimminous mixture samples
Bituminous mixture samples (prepared earlier) 2. Universal Testing Machine (UTM)
The circulating-air environmental chamber is set to 40 °C
The British DD226 standard testing is set up
Setup parameters (pre-load)
Setup parameters (loading)
Test data is stored automatically and graphs are shown in the next chapter
- Gap Graded
- Continuous Graded
- Open Graded
- Dense Graded
- MARSHALL STABILITY TEST
- Gap Graded
- Continuous Graded
- Open Graded
- Dense Graded
The voids in mineral aggregates (VMA) and voids in the total mixture values are obtained from calculations. Marshall test in air in water. density Stability Flow VMA Voids in the total mixture. asphalt content Figure 11: Stability vs. AC weight of mii<%). Percentage of air voids in compacted mixture using the average of the limits given in the JKR Standard Specification for Road Works [i.e.
From the graph, linear equations for the new Smix are obtained (equations are shown in Figure 31).
Sbit)v =
From the Dynamic Creep Test performed, the creep stiffness for each sample is recorded (refer to Appendix 4). Average Smix refers to the average creep stiffness of the mix based on the results of the Dynamic Creep Test. To find the pit depth, the first step is to calculate the viscous component of the bitumen stiffness modulus, (Sbit)v.
XiXAI )OOR PROJIXETX -XYEJSEIEFA'iI0\. Sbit)v = the viscous component of the stiffness modulus of the bitumen rj == the viscosity of the bitumen as a function of PT and ring and ball.
Rj = CmXHx
E-05 Gapgraded Power(Gapgraded)
As shown in Figure 32, the grade with the highest rut depth is a gap graded mix, followed by open graded and continuous graded mix. Close-graded mix shows the lowest rut depth, indicating the highest resistance to creep. As described by Uzan, mm track depth is taken as the maximum allowable track depth for maintenance purposes.
For the dispersion mix, the coarse aggregate used is only 25%, while the fine aggregate used is 63%. Since the amount of coarse aggregate is small, stone-to-stone contact is minimal. Stone-to-stone contact is very important, as bituminous mixtures develop their strength both due to the joint of the aggregate and the viscosity of the binder.
Larger sizes make coarse aggregates more likely to make physical contact or aggregate. Interlocking properties have been shown to be important for increased rutting resistance of surface layers in high. Comparison of Graded-Grade Mixture with Open-Grade Mixture; coarse aggregates used in open graded mixes are much higher (90%) than those used in empty graded mixes (25.
Although the average rut depth shows that open graded mix is the third best mix in terms of creep resistance, other aspects such as durability and strength must also be considered. For densely graded mix, the coarse aggregate used is 51%, the fine aggregate used is 42%, while the filler used is 7. Compared to slot graded and open graded mix, the coarse aggregate and fine aggregate used are "optimal"; not too much coarse aggregate, not too much fine aggregate.
The optimal content of coarse aggregate ensures good sealing properties, while the optimal amount of fine aggregate helps to fill the air voids. 1998), air voids play an important role in the durability and stability of pavements. While for continuous mix, coarse aggregate used is 54%, fine aggregate used is 38% and aggregate used is 8%. Aggregate proportions are similar to densely graded mixes, but continuous graded mix has lower rut resistance compared to densely graded mix.
IAYAEA BY EUiMAYEXi CliU EXCY 4299
High permeability to water encourages the stripping of the bitumen from aggregate particles, and also endangers the underlying layer and the base layer.
CHAPTERS
CONCLUSION AND RECOMMENDATION
Other tests such as the Flaking and Elongation Index and the Los Angeles Abrasion Test should also be performed to study the effect of aggregate shape on the behavior of the wheels. An example of a coarse aggregate that can be used is crushed limestone, while a fine aggregate that can be used is mining sand. In addition to studying aggregate properties and their effects on creep performance, other tests such as fatigue testing and wheel tracking testing can be performed to measure strength and durability.
Hawai 'i Asphalt Paving Industry (HAPI), HAPIAsphalt Pavement Guide
Works."
Rubber modified dense surface layer, wjyw.gjes^emson.edii/arts/DGSCpdf wjyw.gjes^emson.edii/arts/DGSCpdf. Rubber Modified Open Friction Course, wwwxe_s.clemson.edu/arts/OGFC.pdf wwwxe_s.clemson.edu/arts/OGFC.pdf.
IAYAX ! BY. XECjAYEAX CE1Y EEC 4299
APPENDIX
FHWA
Trial Mix 8
Since the a value is -ve, eliminate this mix
IAL2
ENDK2
Gbcm* Pta VMA =100-
Gbam
Pca + Pfa + Pmf
Gbca Gbfa Gbmf
Pca = percentage weight of coarse aggregate Pfc = percentage by weight of fine aggregate Pmf - percentage weight of mineral filler. Gbca = bulk specific gravity of coarse aggregate Gb& = bulk specific gravity of fine aggregate Gbmf = bulk specific gravity of mineral filler.
100 vJrap
Pta Pac
Gea Gac
THiB,-C
ForN = 1
ForN*1
P ntinuous
