The quality of asphalt concrete in flexible pavements plays a major role in the performance and durability of these pavements. The literature review revealed that Superpave mix design provides better performance than Marshall method, especially for roads exposed to heavy traffic loadings and climatic changes.

What is the Superpave method?

The Superpave system ties asphalt binder and aggregate selection into the mix design process, and considers traffic and climate as well. The compaction devices from the Hveem and Marshall procedures have been replaced by a gyratory compactor and the compaction effort in mix design is tied to expected traffic.

What is Marshall mix design method?

The Marshall Mix Design method was originally developed by Bruce Marshall of the Mississippi Highway Department in 1939. The main idea of the Marshall Mix Design method involves the selection of the asphalt binder content with a suitable density which satisfies minimum stability and range of flow values.

When was Superpave created?

After five years of intensive research and testing, SHRP introduced the Superpave system in 1992.

What is the main difference between Superpave and Marshall mix design methods?

Marshall mix design primarily address the determination of asphalt binder content, while Superpave addresses all element of mix design. The Marshall design/construction method requires in most cases compaction 95% or greater of the maximum lab value.

What is Superpave binder?

A New Approach to Asphalt Mix Design Rather than a specific process or procedure, Superpave is a performance-based specification for asphalt binder and volumetric mixture design. … A system of classifying asphalt binder based on its performance response to temperatures and aging characteristics.

What is dust to binder ratio?

During design, mixtures that are above the maximum density line at the 2.36-mm (for 19-mm or smaller mixtures) or 4.75-mm (for 25-mm or larger mixtures) critical sieve should have a dust-to-binder ratio of no more than 1.4.

What pavement distress is evaluated by the Superpave testing?

Using the Superpave system, materials and mixes can be designed to reliably perform under any conditions of load and environment. It evaluates the binders’ abilities in resisting rutting, fatigue and low temperature cracking based on their rheological properties at the anticipated pavement temperatures.

What is Superpave 19?

Superpave 19.0 Binder course mix for Traffic Category A, B, C, D, and E roads. Superpave 19.0 is similar to the traditional HL 4, HL 8, and (HS) HL 8 mixes according to OPSS 1150. Superpave 25.0 Large stone binder course mixes for use when thicker binder course lifts are required.

What is Superpave testing?

Overview. The Superpave Shear Tester (SST) (Figure 1) is used to characterize a HMA mixture’s resistance to permanent deformation (rut resistance). … Results from the RSCH test are used to determine the accumulation of permanent shear strain with load repetitions.

Article first time published on

What is 19mm asphalt?

Asphalt Paving ‐ 19mm Binder Course 19mm Binder Course is applied in one layer, is as strong as regular base and has a sufficient amount of liquid asphalt to roll into a very durable surface. The difference is that the texture is coarser than 9.5mm Wearing Course.

How do you perform a Marshall stability test?

1. Specimens are heated to 60 ± 1 °C either in a water bath for 30 – 40 minutes or in an oven for minimum of 2 hours.
2. The specimens are removed from the water bath or oven and place in lower segment of the breaking head. …
3. The flow meter is placed over one of the post and is adjusted to read zero.

What is Marshall test on asphalt?

The Marshall Test is a popular and proven method to measure the load and flow rate of asphalt specimens, beginning with compaction into molds using manual or automated Marshall Compactors, and conditioned in a Water Bath at the specified temperature.

Which are the two major parameters considered in Marshall mix design?

9. Which are the two major parameters considered in the Marshall mix design? Explanation: Density and stability are the two important features that are used in the Marshall mix design procedure.

What parameters are calculated in Marshall mix design?

Gmm = maximum specific gravity of paving mixture (no air voids) Pmm = total loose mixture = 100% Ps = aggregate, percent by total weight of mixture (P1 + P2 + P3 + Pn) Pb = asphalt, percent by total weight of mixture. Gse = effective specific gravity of aggregate. Gb = specific gravity of asphalt.

What are the steps in bituminous mix design?

• Aggregate selection.
• Asphalt binder selection.
• Sample preparation (including compaction)
• Stability determination using the Hveem Stabilometer.
• Density and voids calculations.
• Optimum asphalt binder content selection.

What does Rice mean in asphalt?

The Rice Test for Specific Gravity of Asphalt is a common test that measures the Theoretical Maximum Specific Gravity (Gmm) of asphalt specimens. The test is an integral part of the quality assurance of asphalt mixtures. Free and entrapped air is removed from the asphalt sample to prepare for the test.

What is PG grade?

The Performance Grade (PG) system is the method of categorizing an asphalt cement binder. used in asphalt pavement relative to its rated performance at different temperatures.

How does the Superpave binder specification relate to performance?

SHRP research developed the Superpave binder specification to be generic, performance based and climate driven. It addresses the pavement distresses of rutting, fatigue, and thermal cracking. Complete testing requires a lengthy process in person-hours and elapsed time.

Is Superpave an HMA?

Superpave consists of (1) an asphalt binder specification, (2) an HMA mix design method and (3) HMA tests and performance prediction models. Each one of these components is referred to by the term “Superpave”.

What is the best grade of asphalt?

The 60-70 grade is usually used only in pavements where traffic is very heavy such as principle city streets and very heavily trafficked rural highways. The second grade, 85-100, is by far the most widely used material for plant mixes and is suitable for most pavements.

What is Aashto m320?

AASHTO M 320, 2021 Edition, 2021 – Standard Specification for Performance-Graded Asphalt Binder. This specification covers asphalt binders graded by performance. Grading designations are related to the average seven-day maximum pavement design temperature and the minimum pavement design temperature.

What is the Superpave 12.5 FC2?

Superpave 12.5 FC2 Surface course mix for use on Traffic Category D and E roads that provides superior rutting resistance and skid resistance through aggregate selection. Superpave 12.5 FC2 is similar to the traditional DFC mix according to OPSS 1150.

What is HL3 asphalt?

HL3A – This driveway grade asphalt results in a smoother finish, perfect to define the look of your entire home or business. HL3 – This commercial grade asphalt is used in situations where a more durable surface is needed. HL8 – Base asphalt is used for multi layered applications.

What is FC2 asphalt?

Surface course mixes requiring superior Page 4 skid resistance are specially designated as 12.5 mm FC1 and 12.5 mm FC2 mixes (FC stands for Friction Course) and they are similar to the HL 1 and DFC mixes.

What grade PG is needed for 98 reliability?

The common minimum reliability used is 98%, so that means when the PG 64-10 binder is selected, the asphalt binder in the AC pavement should perform satisfactorily under normal traffic condition at the location where the extreme pavement temperature are within the range of −10°C and 64°C throughout its service life …

What is PG bitumen?

Performance Grade (PG) Bitumen is bitumen which is graded based on its performance at different temperatures. In Superpave grading system, binders are classified according to their performance in extreme hot and cold temperatures and called as performance grade (PG) bitumen.

What are the different methods used to grade asphalt binders?

Three different asphalt grading systems are normally used; they are penetration grading system, viscosity grading system and performance grading (PG) systems.

Which property is most important for asphalt binder?

Typically, the most important physical properties are: Durability. Durability is a measure of how asphalt binder physical properties change with age (sometimes called age hardening). In general, as an asphalt binder ages, its viscosity increases and it becomes more stiff and brittle.

What is i5 asphalt?

The I-5 or top is commonly used for homeowners and businesses. I-4 or Commercial top consist of a mixture of ¾ inches of stone and is used when added stability ans strength is needed for the asphalt. … The oil content is added to the mixture to combine, then applied to the area for the asphalt driveway.

What is B mix asphalt?

4.2.1 Conventional Mix B It is a Marshall 50 blow designed HMA, using 150/200 A penetration grade asphalt cement, with a typical design asphalt content of ± 6.0%.