1.
TITLE: Loss angles abrasion and aggregate
impact value.
2.
AIM OF THE
EXPERIMENTS: To knowledge the difficulties course of Aggregate that through Angles abrasion loss test.
In experiment 7, The
test is to determine the total impact value of coarse aggregates as IS: 2386
( Part IV ) – 1963
3.
THEORY:
In experiment 6, The Testing for Loss Angles Abrasion in Machine composes a
hollow through steel cylinder and closed in both ends, an inside having diameter of 28" and an inside
length 20". Cylinder is placed in the shafts stub that will be attached to both ends of the
steel cylinder, which do not enter and mounted in such a way that it can be
rotated around its center in a horizontal position. Slot is provided in the
cylinder for the introduction of the test sample and that it can be closed
dust-tight with the removable cover closed in place. The cover is designed to
preserve the Contour of the cylindrical inner surface. They are placed on the
shelf so the charges do not fall into the cover or come in contact with them
during the probationary period. Steel rack removable radial projection 3-
½" into the cylinder and extending its full length is mounted along one
thing of the interior surface of the cylinder. Also, The shelf is such
thickness and so mounted by bolts or other approved means to be strong &
firm. The position of the shelf, which is like the distance from the shelf to
the opening of the measure along the perimeter of the cylinder, which should be
in the direction of rotation of at least 50 ".If It stops the lid on the
bottom, so it can be difficult to access the site, and move the barrel through
the panel and then the weight of the external push forward and then reverse
with the withdrawal of move the barrel to the wanted position.
In experiment 7, the
road aggregate it was has been
manufactured to a specified grading stockpiled,
transported, spread loaded into trucks, tipped, and set up when was
manufactured. Some degradation may take place and result in a change in grading
and the production of excessive and undesirable fines if the aggregate is weak.
However, when an aggregate complying with a specification at the quarry in the
pavement, it may fail to do so. It can be quite high for the Granular base layers and surfacing to be prone
to repeated loadings from big truck tyres and stress at the contact points of
aggregate particles. These crushing tests can manifest aggregate properties
vulnerable to mechanical degradation of this form. The table below shows requirements.
A . KAIKADE, J . (2005).
4. APPARATUS:
Experiment
6:
Standard Sieves , Los Angeles Machine , Drying Oven , Steel balls Charge , Scales and
1.70
mm(No.12) sieve.
Figure 6.1: Equipment’s of experiment
Experiment
7:
· Weighing Tools: Impact testing machine conforming to IS: 2386 Sieves
and sizes 10 mm 2.36 mm and 12.5 mm).
·
A cylindrical metal measure
of ( 75 mm dia.)+( 50 mm depth ).
5.
MATERIALS:
Experiment 6
Aggregate
Coarse
6. EXPERIMENT METHOD:
Experiment 6:
1.Wash
and so oven‐dry
5000 grams sample of the aggregate - dry to a constant mass at
230 ºF ( + / - 9)( 110 ° C ( + / -
5 )) nest sieves in order of decreasing size of the opening, and place
sample of aggregate on the top sieve.
2.
sample of separate to the individual size fractions with sieving
material retained weight in each sieve.
3. Reassemble material sieved to the required grades - the total
mass of the nearest record 1 gram.
4.
Rotate the drum for five-hundred revolutions at a constant speed of 30 to
thirty -three rpm - approximately a quarter-hour - shelf
recommendations up charge + sample at
bottom of drum - charge
+ sample dropped as drum goes
around crushing - charge & sample roll at lower side grinding.
5. It should remove sample from machine.
6. Dry Sieve over a No. 12 sieve
7.
Passing Material=degraded
8.
Retained Material=intact
9.
Wash and oven retained dry material ( if required )
10.
Near of weigh 1 gram
11.
Calculate percent loss because abrasion with calculating the difference between
the original sample of weight and larger particles for retained material. The difference weight is reported as a percent from the
original weight and called " loss
of percent ".
Experiment 7
1) The sample test
should adjust to following grading:
Passing on IS : (12.5 mm
)Sieve 100 %
Retention through IS: (
10 mm ) Sieve 100 %
2) The sample which
will be oven-dried for four hours from 100 to 110 oC temperature and cooled.
3) The measure is about
one - third full prepared aggregates and compacted with (25 ) strokes of the
compacting rod.
A more similar quantity
of aggregates will be added and a further tamping of ( 25 ) given strokes. The
measure will finally be filled to surplus, tamped (25)times and the overflow
aggregates struck off, using a tamping rod for straight edge. The net weight
aggregates in the measure will be determined to the nearest g ( Weight A ).
A) The
effect testing machine cup will be fixed securely properly on the foundation of
the machine. The total of the sample test
placed in it and tamped by(25) strokes for tamping rod.
B) The hammer will be
elevated to ( 380 mm ) over an upper surface of the aggregates in the cup and
allowed to fall freely onto the aggregates. sample test will be prone to an
overall total of ( 15 )such blows, and each one will be delivered at an
interval which not less than one second.
7.
DATA
AND RESULTS OF THE EXPERIMENTS:
Loss angles
abrasion
2500 grams of 9.5 mm
2500 grams of 12.5 mm
Retained from 1.7mm = 4285 grams
LAN= ( 5000 - 4285
/ 5000 )
* 100% = 14.3%
Aggregate impact
value
1-
The sample will removed by IS sieve (2. 36mm). The fraction moving will be
through ( Weight B ) and the fraction salvaged on the sieve will be ( Weight
C). So, if the overall weight B+C is
less than first ( weight A ) by more the 1 gram, the end result will be
rejected and a new test will be achieve.
2-
The weight of rate fines formed to the overall sample weight should be as a
percentage.
Weight
1= 38.2 grams
Weight
2= 33.6 grams
W. of
Coarse Aggregate =Weight 2 – Weight 1 =38.2-33.6= 4.6grams
passing A = 33.6 + 4.6 = 38.2grams
retuning B
= 33.6grams
Aggregate
impact value= ( B / A ) x
100 %
Aggregate
impact value= ( 33.6 / 38.2) x 100% =
87.95 %
8. Discussion
Experiment 6:
The Loss angles test to
scrape test pilot. Therefore it is not directly linked to the performance in
the field of aggregates. Observations generally do not reveal A good
relationship between the values of Loss angles abrasion and field performance. Loss Angles friction
loss is able to field performance expected. Specially, the test may not be
satisfying for some types of aggregates. Some aggregates, such as some
limestone and slag, tend to perform adequately in the field but have high Loss
angles abrasion. Loss angles abrasion loss seems to be well related with dust
be during handling and production of HMA in those aggregates with higher Loss
Angles. values of abrasion loss and
usually generate more of dust. Through the result gained in the experiment, it
is clear that rubble fit in the use of construction such as the foundation
because it was given less than 17% and this resists external affecting factors.
We all used, 11 balls for 500 cycles and which gave required result of specifications
Experiment 7:
This experiment discussed the geological
description of the aggregate, particle size and the source quarry. Also, it
showed the applied force, dry is different in the weight and the masses
of material after sieving while
calculations for result was 5.3% .
Moreover, it will discussed the results using in the range and collect results
using from other group, then compare the
obtained values. Millard, R.S. (1993).
9. Conclusion
The experiment
investigated the possibility of assuming
the loss angles abrasion from the crushability index and the results of loss angles abrasion, density, crushability
and porosity tests . These tests were analyzed using multiple regression
analyses and simple. Important relations
were generally gained from both multiple regression analyses and simple.
The Simple equation is practical and reliable enough for the estimation of the
loss angles abrasion from crushability index. However, who wants to make more
precise assumption which can alternatively using two multiple regression
equations.
No comments:
Post a Comment