The end result of a successful mix design is a
recommended mixture of aggregate and asphalt binder
. This recommended mixture, which also includes aggregate gradation and asphalt binder type is often referred to as the job mix formula (JMF) or recipe.
How do you calculate job mix formula?
The job-mix formula for each mixture shall
establish a single percentage of aggregate passing each required sieve size and a single percentage of bituminous material to be added to the aggregate
.” Here you see HMA mix specimens, with OGFC specimens on the left and dense-graded mix specimens on the right.
What means job mix?
job mix
The set of jobs actually being executed within a multiprogramming system at any one time
.
What is meant by asphalt job mix formula?
Another term for mix design is the “job mix formula” or “JMF”. The two main components in hot mix asphalt are
mineral aggregate and the liquid asphalt binder
. … The selected aggregate is prepared and passed through a series of sieves that are placed on top of each other in decreasing size.
What is mix design of asphalt?
Mix design is a process to manipulate three variables: (1) aggregate, (2) asphalt binder content and (3)
the ratio of aggregate to asphalt binder with the objective of obtaining an HMA
that is deformation resistant, fatigue resistant, low temperature crack resistant, durable, moisture damage resistant, skid resistant …
What is blending of aggregates?
Aggregate blending is a process that blends available aggregates to create a blend that meets gradation specifications while minimizing the unit cost of the blend. … Aggregate blending is
a process for determining the appropriate proportions of aggregates so that the blend meets gradation specification limits
.
How do you make a concrete mix?
- Step 1: Slump Flow. …
- Step 2: Aggregate Size. …
- Step 3: Mixing Water and Air Content. …
- Step 4: Concrete Strength and Water/Cement Ratio. …
- Step 5: Coarse Aggregate. …
- Step 6: Fine Aggregate. …
- Step 7: Adjustment for Moisture in Aggregates. …
- Step 8: Summary Design.
What is Marshall mix design?
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
.
How do you perform a Marshall stability test?
The basic Marshall test consists essentially of crushing a cylinder of bituminous material between two semi-circular test heads and recording the maximum load achieved (i.e. the stability) and the deflection at which the maximum load occurs (i.e. the flow).
How is Marshall mix design calculated?
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.
What is Type 3 asphalt?
IKO Asphalt Type 3 is a
proven waterproofing material
and is suitable for use in selected damp proofing and waterproofing applications. The product is oxidized bitumen intended for use with glass felts, modified rolls, insulation and cover boards with a slope of 0–3:12 (0-25%).
What is the minimum thickness of asphalt?
Asphalt Thickness:
Asphalt driveways need to be a minimum of
2” thick
and are typically 3” (compacted).
What are the main objectives of performing a mix design?
Objectives of Mix Design
1)
To achieve the designed/ desired workability in the plastic stage
. 2) To achieve the desired minimum strength in the hardened stage. 3) To achieve the desired durability in the given environment conditions. 4) To produce concrete as economically as possible.
Why do we blend aggregates?
A. Aggregate blending is the process of intermixing two or more fine
or coarse aggregates to produce a combination with improved grading or other properties
.
What is well graded aggregate?
Well graded : Well-graded aggregate has
a gradation of particle size that fairly evenly spans the size from the finest to the coarsest
. A slice of a core of well-graded aggregate concrete shows a packed field of many different particle sizes. It is characterized by the S- shaped in gradation curve.
How is combined aggregate gradation calculated?
Determine the theoretical combined gradation from the individual gradations. This is done by
multiplying the percent retained on each sieve for the individual gradations by the relative portion of the aggregate volumes
. Then total the percent retained of each product for each sieve size.
