Analysis Stability Of Asphalt Concrete Binder Course (AC-BC) With Fly Ash And Bottom Ash Substitution Material

Fly ash and bottom ash are ash produced from the process of burning coal as a source of energy in the steam generating unit of a coal-fired power plant (PLTU). Bottom ash is ash that forms at the bottom of a coal-burning furnace and settles there. In this research, fly ash is used as filler substitution and bottom ash is used as fine aggregate substitution (sand). The purpose of the study was to obtain a suitable Job Mix Design (JMD) for Asphalt Concrete - Binder Course (AC-BC) with fly ash and bottom ash substitution materials. To determine the effect of optimum asphalt content on the values of stability, flow, Marshall Quotient, VMA, VIM and VFB obtained from result of the Masrhall test. Based on the results of Marshall testing, the results show that Analysis Stability Of Binder Course Asphalt Concrete (AC-BC) With Fly Ash And Bottom Ash Substitution Material produces the highest VMA value of 14.462% and the highest VIM value of -1.88%, meaning that there are many gaps in the mixture containing asphalt so that it becomes waterproof and hermetic. The highest stability and MQ values are stability of 1955.55.34 kg and MQ of 1241.13 kg/mm. The appropriate Job Mix Design (JMD) for Asphalt Concrete - Binder Course (AC-BC) with fly ash and bottom ash substitution materials is the composition of Fly Ash at 0%, 50%, and 60% of the total cement while for the use of Bottom Ash from the total sand at 0%, 50%, and 60%.


Introduction
Asphalt roads in Indonesia require maintenance or restoration to address worn-out pavements, cracks, potholes and other general deterioration.Flexible pavements are made of aggregates and binders that carry the traffic load.Most of the time, crushed stone or river stones are used as aggregates, and binders for pavements include clay, cement, and asphalt [1].Waste utilization is currently progressing.It may also lessen the need for non-renewable natural resources like stone and sand, in addition to lowering the quantity of garbage that builds up over time.When coal is burned in the steam generating unit of a steam power plant (PLTU), ashes known as fly ash and bottom ash are created.Nonetheless, due to their massive production, the majority of ash types-including fly and bottom ash-are disposed of in landfills [2].1321 (2024) 012021 IOP Publishing doi:10.1088/1755-1315/1321/1/012021 2 Fly Ash is the term for ash produced from combustion gases that fly freely in the air and are captured by ash capture machines such as electrostatic precipitators or filter bags [3].Bottom ash, on the other hand, is the ash that forms at the bottom of a coal-burning furnace and settles there.Bottom ash is often used in construction applications, such as a substitute for sand in concrete mixes, road embankments, and sound barriers.It is coarser and heavier than fly ash.Both types of solid waste are left over from coal-fired power plants and if not managed properly can damage the environment.To reduce the adverse impact on the environment, adequate treatment and management is required.

Aggregate
Two aggregate grades were produced using crushed limestone [4].Aggregate is one of the most important elements in pavement construction, according to [5].Road construction projects may consist of 90-95% aggregate by weight or 75-85% aggregate by volume.Aggregates can be divided into three parts based on their grain size: In accordance with the description of Division 6 of the General Highway Specifications 2018 the following requirements or standards have been established for coarse aggregate, fine aggregate, and filler materials.

Coarse Aggregate
For design mixes, the material left after passing sieve number 4 (4.75 mm) called coarse aggregate should be strong, durable, not contained clay or any other materials that aren't wanted, and clean.With one or more flat surfaces crushed, the coarse aggregate should have the required angles and have a weight percentage exceeding 4.75.mm.Table 1 illustrates the coarse aggregate required for highways.

Asphalt Concrete Binder Course
Asphalt Concrete Binder Layer is a bituminous base layer that is used as a base and binder.It also has an asphalt bitumen-rich concrete layer that is about 5 to 6% thicker than the base layer (e.g., ATB = treated substrate).The gravel base layer serves as the load-bearing component of the road layer and contains only about 4.5 percent asphalt.General requirements are load capacity (beam effect, high value stability), the ability to transfer loads from vehicle wheels to the underlying layers, and a waterproof surface which means water cannot easily enter the vehicle through cracks or holes without immediate repair of the underlying layers [6].

Fly Ash
A byproduct of burning coal in power plants is fly ash.Fly ash is used as a filler in AC-BC laston mixes.
Fly ash is the final coal waste to be released from the combustion chamber.Fly ash is a light graycolored powder.Fly ash, an inorganic oxidant, has 58.20% silicon dioxide (Sio2).Fly ash also includes iron oxide (Fe2O3), calcium oxide (CaO), magnesium oxide (MgO), calcium oxide (TiO2), aluminum oxide (A12O3), carbon, and passive rust (P2O5).Fly ash from B3 waste has a high concentration of heavy metals.Figure 1 depicts the physical form of bottom ash.

Bottom Ash
In this test, the AC-BC Laston mixture was filled with bottom ash waste (fine aggregate).The ash that remains after burning coal in a steam power plant's boiler is known as bottom ash.Bottom ash is pozzolanic and comes in two varieties: dry bottom ash and wet bottom ash, also known as boiler slag.
The size of the microscopic particles depends on the kind of furnace.Figure 2 bellow depicts the physical form of bottom ash.

Methods
An experimental approach was used in the analysis methodology of this research.Conducted in the laboratory of road pavement Faculty of Engineering, Sultan Agung Islamic University Semarang with the aim of obtaining data that can be processed with the aim of developing waste.This research activity uses non-functional or waste materials with materials from coal in the form of bottom ash and fly ash which will become a substitute for substitutes and mixtures of fine aggregates and fillers where each mixture in this research is carried out based on the Asphalt Concrete Binder Course (AC-BC) mixing system with Bina Marga inspection procedures.The research and testing scheme is a series of testing stages planned methodically by the researcher so that everything from the beginning of the research process to the data collection stage and the conclusion of the proposal can be done appropriately in accordance with applicable standards and easy to understand.This research is in the form of testing related to Indonesian Standards.If there are procedures that are not listed in the SNI, then other common procedures such as AASHTO, ASTM, and other procedures are used.

Marshall Test
The most popular laboratory technique for evaluating the performance of hot mixes is Marshall testing, which involves utilizing Marshall instruments to measure the plastic mixtures' stability and fatigue values [7].A press fitted with a 2500 kg testing or proving ring is known as Marshall test equipment.The cylindrical proving ring with a diamater of 10 cm and a height of 7.5 cm is prepared in the laboratory in a test specimen mold using a pounder weighing 4.356 kg or 10 pounds and a drop height of 45 cm or 18 inches, loaded with a capacity of 50 mm/minute.
A number of test specimens with varied amounts of asphalt were subjected to the Marshall test in order to determine the ideal mix content [8].The results of the test specimens with varying asphalt content were tested and analyzed to obtain: 1. Asphalt content with percentage of voids in the mixture.

Results and Discussion
Using the Marshall testing method, an asphalt penetration 60/70 standard combination and a mixture supplemented with fly ash and bottom ash as aggregate substitutes were compared for AC-BC flexible pavement.The research's findings are listed below, and they will be explained in the following manner.:

Optimum Asphalt Content Research Results
Planning the optimum asphalt content with asphalt levels including 4%; 4.5%; 5%; 5.5%; 6%.Then conduct tests by selecting the optimum asphalt content of the 5 variations and intended for determining the asphalt content on the test specimen.Asphalt content testing uses 3 specimens in each variation of asphalt content so that a total of 21 specimens from the 7 variations are intended.After conducting research on each test specimen with the same research method by testing the properties of various mixtures including Bulk Density, Air voids, PRD air voids, Voids in aggregate, Voids filled with asphalt, Marshal stability, melting, and Mashall Qoutient.In this test, the optimum asphalt content was found to be 5.7%.

Job Mix Design
The planned asphalt composition is by substituting Fly Ash with levels of 0%, 50%, 60% of the total cement while for the use of Bottom Ash from the total sand with levels of 0%, 50% and 60%.The composition of each mixture appears in the table that follows :

Marshall Test Result
The Marshall test's output, the value of Optimum Asphalt Content, will serve as the Marshall parameters.The Optimum Asphalt Conten value is obtained after obtaining a number of criteria.The metrics that were acquired include MQ (Marshall Quotient), stability, flow, VMA (Void in Mineral Aggregates), VIM (Void in Mix), and VFB (Void Filled Bitumen).
The Marshall Test examination results are displayed in a graph that includes all of the Marshall Test parameter values, which have been found to meet the requirements of the 2018 Bina Marga General Specifications (revision 2), including VMA (Void in Mineral Aggregates), VIM (Void in Mix), VFB (Void Filled Bitumen), stability, flow, and MQ (Marshall Quotient).
The results obtained from the Marshall test in the study were divided into 7 compositions, namely the Marshall test results for normal composition test specimens, sand + bottom ash 50% combination test specimens, fly ash 50% + bottom ash 60% combination test specimens, fly ash 50% + bottom ash 50% combination test specimens, stone ash + fly ash 60% combination test specimens, bottom ash 50% + fly ash 60% combination test specimens, bottom ash 50% + fly ash 50% combination test specimens with 3 test specimens each per composition.Based on the test the result is stated below: 1.According to the findings of the tests conducted on fly ash and bottom ash, it was determined that fly ash waste could be used in place of filler and that bottom ash could be used in place of fine aggregate (sand) because all test requirements were satisfied and the warm asphalt mixture standards were in line with the 2018 Bina Marga general specifications in refinement 2 section 6.4, that the filler contains material that passes the No.200 sieve (75 µ) at least 75% of its weight with the results of passing the No.200 fly ash sieve, namely 100% and 100%.(75 µ) at least 75% of its weight with the result of passing the No.200 fly ash sieve, namely 100% and fine aggregate has a maximum No. 200 sieve of 10% with the result of passing the No.200 bottom ash sieve, namely 0.29% and has a sand equivalent value in fine aggregate of at least 50% with the result of sand equivalent for bottom ash of 53.028%.Silica (SiO2) in fly ash is chemically formed with calcium hydroxide through the hydration process of cement and binding agents.In addition, bottom ash and fly ash have good adhesion and cohesion.
2. Based on the Marshall test results and Marshall parameters, the results show that the ASPHALT CONCRETE -BINDER COURSE (AC-BC) ANALYSIS WITH FLY ASH AND BOTTOM ASH SUBSTITUTION MATERIALS AC-BC produces the highest VMA value of 14.462% and the highest VIM value of -1.88%, meaning that there are many gaps in the mixture containing asphalt so that it becomes waterproof and hermetic.Fly ash and bottom ash can strengthen the bond between aggregate and asphalt and maintain the slip resistance of asphalt on aggregate.The highest stability and MQ values are stability of 1955.55.34 kg and MQ of 1241.13 kg/mm.The high stability value means that the mixture cavity is low, so that the gap between the mixture can be filled with material, resulting in strength in the mixture.The use of fly ash and bottom ash can increase flexibility, shear resistance, high inter-grain locking.Fly ash contains pozzoland compounds that increase stability.The highest MQ means the mix has strength and resistance to deformation.Fly ash and bottom ash make the cohesion of the mixture increase, the density of the mixture increases, and the interlocking between aggregates increases.In addition, it produces the lowest flow value of 1.58 mm, the shape change is small and bottom ash is good at melting. 3. To obtain a suitable Job Mix Design (JMD) for Asphalt Concrete -Binder Course (AC-BC) with fly ash and bottom ash substitution materials.The planned asphalt composition is by substituting Fly Ash with levels of 0%, 50%, and 60% of the total cement while for the use of Bottom Ash from the total sand with levels of 0%, 50%, and 60%.For the first composition, namely: 1) Normal Job Mix Design In the normal asphalt mixture here the composition used does not use additional FABA (Fly Ash and Bottom Ash) materials but only uses a standard mixture as we often see when making asphalt.
2) Job Mix Design 50% Fly Ash Substitution In the 50% Fly Ash Substitution Asphalt Mix here the composition used is almost the same as the composition used by the normal asphalt mixture, but in this mixture Fly Ash is added by 223.2 grams or 18.6% of 100% of the entire mixture.
3) Job Mix Design for Fly Ash 50% and Bottom Ash 50% Substitution In the Fly Ash 50% and Bottom Ash 50% Substituted Asphalt Mix here the composition used is almost the same as the previous composition only in the composition of the asphalt mixture used at this time using 2 mixtures at once, namely Fly Ash and Bottom Ash with additional results from Fly Ash of 223.2 grams or 18.6% of 100% and Bottom Ash of 30.0 grams or 2.5% of 100% of the entire mixture.
4) Job Mix Design for Fly Ash 50% and Bottom Ash 60% Substitution In the Fly Ash 50% and Bottom Ash 60% Substituted Asphalt Mix here the composition used is almost the same as the previous composition, it's just that the composition of the asphalt mixture used at this time only differs in the division of its composition, namely Fly Ash and Bottom Ash with the additional results of Fly Ash of 223.2 grams or 18.6% of 100% and Bottom Ash of 24.0 grams or 2.0% of 100% of the entire mixture.

5) Job Mix Design of 60% Fly Ash Substitution
In the 60% Fly Ash Substitution Asphalt Mix, the composition used here is only using Fly Ash mixture material, which is 60% with a composition weight of 179.04 grams or 14.92% of 100% of the entire mixture.
6) Job Mix Design for Fly Ash 60% and Bottom Ash 60% Substitution In the Fly Ash 60% and Bottom Ash 60% Substituted Asphalt Mix here the composition used is almost the same as the previous composition, it's just that the composition of the asphalt mixture used at this time differs from the percentages, namely Fly Ash and Bottom Ash with additional results from Fly Ash of 179.04 grams or 14.92% of 100% and Bottom Ash of 24.0 grams or 2.0% of 100% of the entire mixture.
7) Job Mix Design for Fly Ash 60% and Bottom Ash 50% Substitution In the Fly Ash 60% and Bottom Ash 50% Substituted Asphalt Mix here the composition used is almost the same as the previous composition, it's just that the composition of the asphalt mixture used at this IOP Publishing doi:10.1088/1755-1315/1321/1/01202113 time differs from the percentages, namely Fly Ash and Bottom Ash with additional results from Fly Ash of 179.04 grams or 14.92% of 100% and Bottom Ash of 30.0 grams or 2.5% of 100% of the entire mixture

Conclusion
Based on data analysis from tests carried out at the Sultan Agung Islamic University Semarang's Pavement Laboratory of the Faculty of Engineering, it can be concluded that fly ash waste and bottom ash can be used in place of filler and fine aggregate (sand), respectively, because all test requirements were met and the warm asphalt mixture standards in the 2018 Bina Marga general specifications were met.

Table 4 .
Job Mix Design With Fly Ash 50%

Table 5 .
Job Mix Design With Fly Ash 50% and Bottom Ash 50%

Table 8 .
Job Each test object is 3 test objects with the aim of comparing each test object where if one of the test objects is not in accordance with the 2018 revision 2 Bina Marga technical specifications and 2 other test objects according to the 2018 revision 2 Bina Marga technical specifications, different tests can be compared with the results.The table below provides specifics about the test objects: The standard AC-BC asphalt mixture with the addition of wax produces the highest VFB value of 133.33% which means the amount of asphalt that fills large voids.The content