In spite of the advances made in agiculture,many people around the world stil go hungry. Why is this the case? What can be done about this problem?

1. Introduction Annually, the

asphalt

concrete

pavement

system suffers failures and road maintenance costs, one of the main reasons for which is cracking. The resistance of the

pavement

against the cracking mechanism is directly related to the ductility and toughness of the

asphalt

binder

. Using a higher amount of recycled materials can expose the

asphalt

pavement

to cracking and reducing

performance

. In

Oregon

, cracking as s destructive agent of

asphalt

pavement

is very common, finding precise test methods and at the same ,time low cost in order to investigate the influence of recycled materials on the behaviour of

asphalt

pavement

has become a necessity. The purpose of

asphalt

mix

design

is to determine an economical and optimum relation between aggregates and binders so that the resulting

mixture

provides sufficient stability to resist deformation and cracking under vehicle loads. The main mission of the

asphalt

mixtures

using in pavements is to stand up to traffic loading under various weather conditions. The Marshall, Hveem and Superpave methods are the three most common

asphalt

mixture

design

methods,

however

, the latter

mix

design

procedure received more attention from engineers and

asphalt

designers after being introduced in the 1990s. The Superpave system is designed based on the

asphalt

binder

and aggregate selection, a

performance

-based hybrid process

,

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so that traffic and environmental condition are

also

taken into account. Superpave

mix

design

consisted of three different

design

levels (

level

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levels

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1,2,3) based on complexity grade,

although

levels 2 and 3 were discarded due to high complexity [1 and 2]. Currently,

asphalt

mix

design

is based on the compatibility between

asphalt

binder

and aggregate and some other characteristics

such

as the physical properties of aggregates.

Although

,

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asphalt

mixture

properties are directly affecting the long-term behaviour of

asphalt

mixtures

, most state Departments of

Transportation

(DOTs) and

asphalt

contractors do not attention to

this

feature.

For example

, the voids determined in the mineral aggregate (VMA)

is

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are

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dependent on the accurate measurement of the physical properties of aggregates, while other considerable issues [3].

In addition

, the volumetric

mixture

design

procedure does not provide a solid approach toward the use of new materials (polymers, additives, rubbers) in

asphalt

mixtures

and there is still no comprehensive understanding of the use of high-volume of reclaimed

asphalt

pavement

(RAP) and its interaction with virgin

binder

matrix.

Hence

, the results of simple volumetrics evaluation may not be reliable. Due to all these reasons, using

performance

tests for cracking and rutting in

asphalt

mixture

design

can be considered

as

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a

design

necessity to be able to determine a more accurate amount/volume of

asphalt

binder

. Many studies are underway to develop a new

method

for

performance

verification-based

mix

design

. The

Oregon

Department of

Transportation

(ODOT) has recently developed a test

method

called

performance

-based balanced

mix

design

, which can be effectively used to evaluate the cracking mechanism in

asphalt

pavements. It has been found that in

this

method

, indices

such

as the typical flexibility index (FI) can be measured with good accuracy for polymer-modified

asphalt

mixtures

produced in the factory and modified,

although

more experimental tests are needed to determine the results accurately. References [1] Sreedhar, S., Coleri, E., Obaid, I.A. and Kumar, V., 2021. Development of a Balanced

Mix

Design

Method

in

Oregon

to Improve Long-Term

Pavement

Performance

.

Transportation

Research Record, 2675(12), pp.1121-1137. [2]

Coleri

Correct your spelling

Colour

, Erdem, Shashwath Sreedhar, and Ihsan Ali Obaid. Development of a Balanced

Mix

Design

Method

in

Oregon

. No. FHWA-OR-RD-21-03.

Oregon

. Dept. of

Transportation

. Research Section, 2020. [3] West, Randy, Carolina Rodezno, Fabricio Leiva, and Fan Yin. "Development of a framework for balanced

mix

design

." Project NCHRP (2018): 20-07.