15 Based on Table 3.1, it can be seen that the parameter of this research are aggregate, both
coarse and fine; marshall properties. Moreover, this research is presented variable namely asphalt concrete modified crumb rubber 3, 4 and 5 and bitumen content 4.5, 5,
5.5, 6 and 6.5.
3.3 Data
Based on Table 3.1 , it can be seen that this research use both coarse and fine aggregates. The coarse aggregate use should have rough surface, angular sharp and clean from other materials
that could interfere with the binding process. Aggregates are used in the form of crush stone in the dry condition. The types of test conduct on aggregates are as follows.
a. Sieve Analysis
This examination is intended to determine the gradation, both coarse aggregate and fine aggregates. Examination procedures refer to AASHTO T27 - 88
b. Specific Gravity and Absorption
Investigation of procedures for coarse aggregate refers to AASHTO T84-88
c. Infinity of Aggregate to Asphalt
Examination procedures refer to the AASHTO T19-88
d. Abrasion with Los Angeles Machine
Examination procedures refer to the AASHTO T96-87 Then, in terms of fine aggregate using, fine aggregate consists of clean sand, fine materials
results split stone or a combinationof both in the dry condition. Inspection types for fine aggregate are as follows:
a. Sieve Analysis
Examination procedures refer to the AASHTO T 27-88. perpustakaan.uns.ac.id
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b. Specific gravity and absorption
Inspection of procedures for fine aggregate refers to AASHTO T84-88. Moreover, in terms of filler inspection, the examination of filler includes:
Absorption: Procedures for checking the sieve analysis for the filler refers to the Bina
Marga 2010 standard with 3 for absorption.
Specific Gravity:Inspection of procedures for filler refers to Bina Marga 2010
standard with 2.5 gramcc. Data collection techniques implemented with an experimental method to several test
specimens tested in the laboratory. The data used in this study include primary data and secondary data.
3.3.1 Primary Data
Primary data is data collected directly through a series of experiments conducted themselves with reference to the existing manual instructions, for example by conducting research testing
directly. The data included in primary data are as the follows:
a. Data Examination Asphalt. b. Data Marshall Properties Test.
c. Data Indirect Tensile Strength Test ITS. d. Data Unconfined Compressive Strength Test UCS.
3.3.2 Secondary Data
Secondary data is data obtained indirectly derived from research or other sources for material same type. In many ways the researcher must receive secondary data according to
what it is. Secondary data used in this study, namely: a. Examination of aggregate data.
b. Testing ITS of AC mixture in previous studies. c. Testing UCS of AC mixture in previous studies.
d. Permeability testing of AC mixture in previous studies. perpustakaan.uns.ac.id
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3.3.3 Sample Preparation of Material
Aggregates used in this study consist of coarse aggregate, fine aggregate and filler. Coarse aggregate is defined as the aggregate retains on sieve size 4.75 mm No.4 while fine
aggregate is defined as the aggregate passing sieve size 4.75 mm No.4 and retains on sieve size 75 μm No.200.
A- Specific Gravity and Absorption of Aggregates. a.
Fine Aggregate
Specific gravity water absorption test of fine aggregate according to these specifications AASHTO T-84 for determination of specific gravity water absorption
of aggregates.
1. Apparatus
a Balance 0 - 6 kg b Pycnometer, Figure 3.1. Volume content for the container needs to be reproduced
within ± 100 mm. c Mold, metal in the form of a frustum of cone with acceptable dimensions of 40 ± 3
mm inside diameter at top, 90 ± 3 mm inside diameter at the bottom, and 75 ± 3 mm in height.
d Tamper, metal having a mass of 340 ± 15g and having a flat circular tamping face of 25 ± 3 mm in diameter.
b. Coarse Aggregate
Specific gravity and water absorption test of coarse aggregate according to AASHTO T 85, for determination of specific gravity water absorption of aggregates.
1. Equipments Apparatus
a Wire basket b Oven 300˚C
c Container for filling water and suspending the basket d An air tight container
e Balance 0-10 kg f Shallow tray absorbent clothes.
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2. Preparation of sample
The sample to be tested is separated from the bulk by quartering or by using sample divider.
3. Procedure
a About 2 kg of the aggregate sample is washed thoroughly to remove fines, drained and then placed in the wire basket and immersed in distilled water at a
temperature between 22 to 32˚C with a cover of at least 50 mm of water above the top of the basket Immediately after the immersion the entrapped air is removed
from the sample by lifting the basket containing it 25 mm above the base of the tank and allowing it to drop 25 times at the rate of about one drop per second. The
basket and the aggregate should remain completely immersed in water for a period of 24 ± 0.5 hours afterwards.
b The basket and the sample are then weighed while suspended in water at a temperature of 22 to 32 ˚C. The weight is noted while suspended in water W1 g.
c The basket and the aggregate are then removed from water and allowed d To drain for a few minutes, after which the aggregates are transferred to one of the
dry absorbent clothes. e The empty basket is then returned to the tank of water, jolted 25 times and weights
in water W2 g. f The aggregates placed in the dry absorbent clothes are surface dried till no further
moisture could be removed by this clothe. g Then the aggregate is transferred to the second dry cloth spread in a single layer,
covered and allowed to dry for at least 10 minutes until the aggregates are completely surface dry. 10 to 60 minutes drying may be needed. The surface dried
aggregate is then weighed W3 g. h The aggregate is placed in a shallow tray and kept in an oven maintained at a
temperature of 110 ˚C for 24 hours. It is then removed from the oven, cooled in air tight container and weighed W4 g.
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B- Aggregate Gradation
The percentages of aggregates required for every sieve size were determined according to the Indonesian standards. Then the samples retained were calculated using the percent passing
for every sample size. Table: 3.2 summaries the upper and lower limit According to Indonesian standards.
Table. 3.2. Gradation Limits For Wearing Course SIEVE SIZE
UPPER LIMIT SPECS.
LOWER LIMIT SPECS.
In Mm
34 19.1
100 100
12
12.5 90
100
38 9.5
72 90
4 4.76
43 63
8
2.38 28
39.1
16 1.18
19 25.6
30 0.59
13 19.1
50 0.279
9 15.5
100
0.149 6
13
200 0.074
4 10
Pan
C-Preparing The Bitumen Samples
In this study will use three types of bitumen: Asphalt 6070 pen, and crumb rubber modified 0, 3, 4, and 5 The bitumen contents for these samples will be rank as 4.5 to 6.5
of the total weight according to ASTM 3515-96 . It has been made the tests for bitumen to
know the physical properties of bitumen.
1. Penetration Test
The penetration test is one of the oldest and most commonly-used tests on asphalt cements or residues from distillation of asphalt cutbacks or emulsions. The standardized procedure for
this test can be found in ASTM D5 ASTM, 2001. It is an empirical test which measures the consistency hardness of asphalt at a specified test condition. In the standard test condition, a
standard needle of a total load of 100 gr is applied to the surface of an asphalt sample at a temperature of 25°C for 5 seconds. The amount of penetration of the needle at the end of 5
seconds is measured in units of 0.1 mm or penetration unit. Figure 3.3 shows a penetration test for bitumen.
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20 Softer asphalt will have a higher penetration; the penetration test can be used to designate
grades of asphalt cement, and to measure changes in hardness due to age hardening or changes in temperature.
Penetration Test Setup
a. Pour the sample into the hood asphalt penetration, let stand 1-2 hours at room temperature soak in a tub of water 25 ° C, for 1-2 hours, clean the needle penetration and
plug. b. Put weight 50 ounces in the needle holder so that the total weight to 100gramsMove the
following sample cup penetration into the tub of water with a temperature below 25°C penetration testers
. c. Set the needle to see the specimen surface Asphalt
d. Remove the needle for 5 + 0.1 seconds. e. Click and read bookmark penetration rate.
f. Lift the needle slowly, test at least 3 times on the same sample.
2. Softening Point Test
The ring and ball softening point test ASTM D36 measures the temperature at which asphalt reaches a certain softness. When asphalt is at its softening point temperature, it has
approximately a penetration of 800 or an absolute viscosity of 13,000 poises. This conversion is only approximate and can vary from asphalt to another, due to the non-Newtonian nature of
asphalts and the different shear rates used by these different methods, Where the Figure 3.4 shows the Softening point Tools.
Testing steps:
a. Preheat asphalt + 25 gr up liquid. b. Put 2 pieces of rings on the brass plate that has been smearedtalk-glycerol.
c. Pour the sample into a ring mold, let stand at room temperature for 30minutes. d. Flatten the sample surface with a knife.
e. Attach the second specimen; Insert the glass vessel containing distilled water. f. Temperatures 5+1ºC
Insert thermometer for determination of softening point. g. Put the steel ball on the test objectSoak in water at 5°C for 15 minutes Heat the vessel
with water temperature rise 5ºCmin. h. Set the heating rate for the first 3 minutes 5 + 0.5ºCmin.
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3. Specific Gravity Test of Bitumen
The test method most often used to determine Gmm is AASHTO T 209. Within the method, there are several options for determining the Gmm but all utilize the same basic principle of
measuring the mass and volume of the loose mix sample to determine its maximum specific gravity. The options within AASHTO T 209 differ by the type of sample container and
whether the container is filled with water or submerged in a water bath. There are three container choices: bowl, flask, or pycnometer.An outline of the procedure is as follows:
a. The dry mass of the loose mix samples are first determined and the mix is then placed in a tare container of one of the types previously mentioned
. b. Water is added to the container to completely cover the sample and a vacuum is applied
to remove entrapped air .
c. The container is then filled with water and the mass determined or it is placed in a water bath and the mass determined
. d. From these mass determinations, the volume of the loose mix and thereby its Gmm is
determined.
4. Ductility Test
The ductility test ASTM D113 measures the distance a standard asphalt sample will stretch without breaking under a standard testing condition 5 cmmin at 25°C. It is generally
considered that asphalt with a very low ductility will have poor adhesive properties and thus poor performance in service. Specifications for asphalt cements normally contain
requirements for minimum ductility, where figure 3.6 ductility test of bitumen machine.
Testing steps:
a. Heat until the liquid asphalt b. Cover the mold with mold ductility glycerin attaches the base plate
c. Pour the test material in the mold of the end to end untilfull d. Refrigerate the mold at room temperature 30 - 40 minutes, and averaged
e. Soak in the tub soaking temperature 25˚C, 30 minutes f. Remove the specimen from the base plate and the sides of the mold. Attach thetest
specimen and the tensile testing machine with a speed of 5 cm per minute until the specimen broke
. g. Read the distance between the specimen holders as broken specimen cm.
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5. Indirect Tensile Strength Test
The crack width formation is dependent on the early tensile strength of concrete. The principle of critical steel ratio also applies in this situation. The amount of reinforcement
required to control early thermal and shrinkage movement is determined by the capability of reinforcement to induce cracks on concrete structures. If an upper limit is set on the early
tensile strength of immature concrete, then a range of tiny cracks would be formed by failing in concrete tension. However, if the strength of reinforcement is lower than immature
concrete, then the subsequent yielding of reinforcement will produce isolated and wide cracks which are undesirable for water-retaining structures. Therefore, in order to control the
formation of such wide crack widths, the concrete mix is specified to have a tensile strength normally measured by Brazilian test at 7 days not exceeding a certain value e.g. 2.8Nmm
2
for potable water. A cylindrical specimen is loaded diametrically across the circular cross section. The loading
causes a tensile deformation perpendicular to the loading direction, which yields a tensile failure. By registering the ultimate load and by knowing the dimensions of the specimen, the
indirect tensile strength of the material can be computed. Below is a figure showing the load fixture and a principal picture of the loading. The detail of ITS formula is presented in
formula 2.2.
6. Indirect Tensile Stiffness Modulus ITSM
The ITSM test is a non-destructive procedure for determining stiffness modulus using repeated load indirect tension. The results are used to assess:Load spreading, Temperature
susceptibility, Durability water sensitivity. The evaluation of the stiffness modulus of bituminous mixtures was done. On the basis of indirect tensile laboratory test results, a
practical model for stiffness modulus prediction in pavement bearing capacity analysis was established and calibrated. The indirect tensile stiffness modulus is shown in Table 3.4 and
can be calculate with formula 2.12.
Table 3.3.ITSM Test Crumb Rubber
20
o
C 40
o
C 50
o
C 6070
3 3
3
3 3
3 3
4 3
3 3
5 3
3 3
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3.3.4 Samples Production of Bitumen Mixtures 1. Samples for Marshall Stability Test
The numbers of samples required are: Three samples for each Percentage of bitumen and 15 samples for each type of bitumen:
Asphalt 6070 pen and Crumb Rubber modified 0, 3, 4, and 5 According to Table 3.4. It is Shows the distribution and number of samples of Marshall testing for each type of
bitumen.
Table 3.4. Number Of Samples Of Marshall Testing. ASPHALT TYPE
PB -1 PB -0.5
PB PB +0.5
PB +1
4.5 5
5.5 6
6.5
AC- Asphalt 6070 Pen
3 3
3 3
3
AC 3 Crumb Rubber 3
3 3
3 3
AC 4 Crumb Rubber 3
3 3
3 3
AC 5 Crumb Rubber
3 3
3 3
3 Total of samples =15 x 4= 60
2. Sample Testing for Unconfined Compressive Strength UCS at OBC
The Unconfined Compressive Strength UCS can be calculated with formula 2.13. The numbers of sample required are:
Two samples of each type of bitumen: Asphalt 6070 pen and Crumb Rubber modified 0, 3, 4, and 5 at each different temperature at OBC; According to Table 3.5
Table 3.5.The Numbers Of Samples Of UCS With Different Temperatures. ASPHALT TYPE
TEMPERATURE TISTING 30 ºC
40 ºC 60 ºC
AC- Asphalt 6070 Pen 3
3 3
AC 3 Crumb Rubber 3
3 3
AC 4 Crumb Rubber 3
3 3
AC 5 Crumb Rubber
3 3
3 Total of samples = 3 x 3 x 4= 3
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3. Sample Testing for Indirect Tensile Strength ITS at OBC
The numbers of sample required are: Three samples of each type of bitumen: Asphalt 6070 pen and Crumb Rubber modified
0, 3, 4, 5 at each different temperature at OBC; According to Table 3.6. It is shows the number of samples of ITS with different temperatures.
Table 3.6. The Number Of Samples Of ITS With Different Temperatures. ASPHALT TYPE
TEMPERATURE TISTING 30 ºC
40 ºC 60 ºC
AC- Asphalt 6070 Pen 3
3 3
AC 3 Crumb Rubber
3 3
3
AC 4 Crumb Rubber
3 3
3
AC 5 Crumb Rubber
3 3
3 Total of samples = 3 x 3 x 4= 36
3.4 Analysis
This research will be started with the sample preparation of materials, as follow: The researcher will conduct the research start from the problem of waste tire that getting higher
than before. Then the researcher will prepare for sample materials, such as aggregate, asphalt 6070 pen, and wet process crumb rubber. In the wet process, the straight binder is initially
pre-heated to around 190
o
C in a tank under hermetic conditions and then transported to a blending tank, where crumb rubber is added. The digestion process, which is the
incorporation of rubber in the conventional binder, continues for a period of 1 to 4 hours, at a temperature of 190
o
C. The process is facilitated by a mechanical agitation produced by a horizontal shaft Visser, 2000. Then, the sieve analysis of crumb rubber is 300. Then,
another material that should be tested is aggregate. In the context of this research, the researcher will test the sieve of aggregate, absorption, specific gravity, gradation and impact.
Moreover, another material for this research is asphalt 6070 pen. The asphalt will be mixed with crumb rubber with 0, 3, 4, 5 combination. Then, the mixture will be test for
penetration, softening point, ductility, coating and specific gravity. In terms of penetration test, the standard that will be used is ASTM D5, for softening point is
ASTM D36, for specific gravity is AASHTO T 209, for ductility is ASTM D113. Then, after all of the test meet the requirement, the next step is focusing on the asphalt mixture with
Marshall Design. Then the test that will be conducted are permeability test, UCS with ITSM 15. Then, the researcher will do comparison between asphalt mixture in terms of strength and
durability perpustakaan.uns.ac.id
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3.4.1 Strength
Compressive Strength is measured on materials, components, and structures. By definition, the ultimate compressive strength of a material is that value of uniaxial
compressive stress reached when the material fails completely. The compressive strength is usually obtained experimentally by means of a compressive test. The apparatus used
for this experiment is the same as that used in a tensile test. However, rather than applying a uniaxial tensile load, a uniaxial compressive load is applied. As can be
imagined, the specimen usually cylindrical is shortened as well as spread laterally. A Stress
–strain curve is plotted by the instrument and would look similar to the following: The compressive strength of the material would correspond to the stress at the red point
shown on the curve. In a compression test, there is a linear region where the material follows Hookes Law. Hence for this regionwhere this time E refers to the Youngs
Modulus for compression. In this region, the material deforms elastically and returns to its original length when the stress is removed.
3.4.2 Durability
Durability. In this study, regression models will be sought that would accurately predict Durability Factors by one or more aggregate andor concrete mixture characteristics.
Thus, Durability is the dependent variable and the aggregate concrete mixture characteristics are the independent variables. The dependent variable is also known as
the “response variable”, and the independent variables are also known as “predictors” or “regressors”. If not included in an interaction, independent variables are also known as
“main effects”. Several different types of regression models were desired, based on the
sort of data that was to be included in each model. For instance, one type of model consisted of aggregate-only independent variables. Usually, model accuracy is sacrificed
by using fewer orless definitive but easier test methods. In terms of durability, the calculation can be conducted with formula 2.14.
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3.5 Flow Chart
The process framework for this study is summarized in Figure 3.1.
No
Yes
Yes No
START Sample Preparation of Materials
Aggregate Asphalt 6070
Impact Gradation
Absorption, SG Sieve Analysis
Wet Process Crumb Rubber Sieve Analysis 16
Mix with Crumb Rubber 3, 4, 5
Standards
Penetration Ductility
Softening point SG
Coating
Marshall Design to get OBC [UCS ITS tests OBC 30ºC, 40ºC, 60ºC] [ITSM 20 ºC, 40 ºC, 50 ºC]
Comparison of results AnalysisBitumen content
Analysis of ITS, UCS PermeabilityTest OBC
AC-Asphalt 6070, Mix with Crumb Rubber 0, 3, 4, 5 Opt. Mixture Composition
Standards
END
Figure 3.1.Flow Chart For Laboratory Process And Analysis
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CHAPTER IV RESULT AND DISCUSSION
4.1General
The main materials used in this research were aggregate, asphalt and crumb rubber. All properties of the materials used were measured for further analysis consideration. Several
tests were conducted in order to measure their properties according to the specification reffered were ASTM.
4.1.1 Asphalt
The properties of asphalt analysed were specific gravity, penetration, softening point and ductility as seen in the Table 4.1, the asphalt properties can fulfil all requirements.
Table 4.1. Properties Of Asphalt Type of
Examination Penetration
0.1mm
a
Specific Gravity
Softening Pointº C
c
Ductility Cm
a
Results 65.27
1.061 52
107.5
Specifications 60-70
Min. 1 ≥ 48 °C
≥ 100 For the detail calculation see appendix A2-A3-A4
In terms of penetration, the calculation comes from all results of penetration for mixture on temperature 25
o
C. Based on the sample result, this research used 3 three samples for penetration with 68 mm, 65.8 mm and 62 mm for result. Then, the average for penetration
score was 65.27 mm. Based on the research result, the penetration for asphalt is 65.27 mm, it means that the penetration met the standard from Bina Marga 2010 with 60-70 mm.
Then, in terms of specific gravity, the asphalt for this research also met the specification. The asphalt for this research has 1.061 for specific gravity, while specification of specific gravity
from Bina Marga 2010 is Min.1. The result of 1.061 gram from many factors, such as weight of asphalt, asphalt content,
asphalt specific gravity. Take an example, the calculation for the first sample, weight of asphalt was calculated as follow:
The weight of asphalt = weight of picnometer filled with asphalt - weight of picnometer with cover
= 54 - 37 = 17 gram perpustakaan.uns.ac.id
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