The steel reamed wheels of animal driven vehicles also cause considerable abrasion of the road surface. Therefore, the road aggregates should be hard enough to resist abrasion. Resistance to abrasion of aggregate is determined in laboratory by Los Angeles test machine. Many tests have been developed to empirically characterize aggregate properties without, necessarily, strong relationships to the performance of final products incorporating an aggregate. The Los Angeles (L. A. abrasion test is a common test method used to measure of degradation of mineral aggregates of standard grading resulting from a combination of action including abrasion and grinding. The standard Los Angeles abrasion test is ASTM C131: Resistance to degradation of small-size coarse aggregate by abrasion and impact in the Los Angeles Machine. Aggregate abrasion characteristics are important because the constituent aggregate in HMA (Hot Mix Asphalt) must resist crushing, degradation and disintegration in order to produce a high quality HMA. The standard L.
A abrasion test subjects a coarse aggregate sample (retained on the No. 19. 0 mm sieve) to abrasion, impact, and grinding in a rotating steel drum containing a specified number of steel spheres. As the drum rotates, a self-plate picks up the sample and the steel spheres, carrying them until they are dropped to the opposite site of the drum creating an impact-crushing effect. The contents then roll within the drum with an abrading and grinding action until the self plate impacts and the cycle is repeated. After the prescribed number of revolutions, the contents are emoved from the drum and the aggregate portion is sieved to measure the degradation as percent loss. 2. 0 Objective a) The objective of this test is to ascertain the degradation of aggregates by abrasion and impact. 3. 0 Apparatus/Equipments The apparatus used in this test are : a. Los Angeles abrasion machine (plate 2) b. Sieves (19mm, 12. 5mm, 9. 5mm, 1. 7mm and pan) c. Sieve shaker (plate 3) d. Balance (accurate to 0. 01g) 3. 1 Picture and the Use of the Equipment Name and picture| Function| Figure 3. 1: L. A abrasion machine| * The L. A.
The Term Paper on Key Tests for Aggrgates
Key Tests for Aggregates The following Key tests to be done on coarse aggregates before using to make the quality concrete are as follows: * Aggregates Crushing Value Test * Aggregates Impact Value Test * Aggregates Abrasion Value Test * Water Absorption Test Aggregates Crushing Value Test: Object This method of test covers the procedure for determining the Aggregate crushing value of coarse ...
Abrasion Machine is used as a quality control tool for aggregates, including crushed rock, gravel and slag. The testing method determines the degradation when subjected to abrasion, attrition, and impact and grinding. | Figure 3. 2: Sieve Shaker| * Use to shake sieves by subjecting vibration toward them. | Figure 3. 3: Balance| * A balance is used to measure mass to a moderate degree of precision and accuracy. | Figure 3. 4: Sieve| * It is use to separate particles of different sizes. * Each sieve has different size of holes * Usually be used with sieve shaker| . 0 Methodology 4. 1 Procedure Approximately 5000g of aggregates including 2500 ± 10g of 19 mm to 12. 5 mm sizes and 2500 ± 10g of 12. 5 mm to 9. 5 mm sizes are used in this test. (Note that this is for aggregates graded mainly between 20 mm and 10 mm size. Sample requirements of other aggregate gradations such as 40 mm to 10 mm, 10 mm to 5 mm, and 5 mm to 2. 5 mm – are given in the ASTM and CSA standards. ) This test procedure is explained below: 1. The sample is washed and dried and later the weight is obtained. 2. The sample is placed in L. A. Abrasion Machine. 3.
Eleven steel balls are added in the machine. 4. The drum is rotated for about 500 revolutions at 30-33 rpm. 5. After being rotated, the sample is removed from the drum and is sieved on no. 12 sieve. Later the sample that is retained on the sieve is washed and dried at the temperature of 1050C to 1100C. The weight of the sample is taken after the sample is cooling down. 4. 2 Flow Chart 4. 3 Picture of the Procedure 5. 0 Result/Calculation Table 5. 1: Result of LAA test Aggregate Size (mm)| Weight Of Sample Before (g)| Weight Of Sample After Abrasion (g)| Loss (g)| 19 – 12. 5| 5000 500 2500| 4190| 810| 12. 5 – 9. 5| | | | Calculation: Weight loss= (Weight of sample before abrasion) – (Weight of sample after abrasion) = 5000 – 4190 = 810 g = 0. 81 kg Percent loss= (weight loss / Total weight of sample) x 100 = 8105000 x 100 = 16. 2% < 30% (JKR standard requirement) The result obtained in this experiment shows that the percent loss due to degradation of aggregates by abrasion is 16. 2%. As the percent loss of the sample is below the range of standard requirement of maximum 30% by JKR, thus the sample is suitable to be used for road works. . 0 Discussion 1. In this experiment, 2500 g of aggregate of size between 14 – 12. 5mm and 12. 5 – 9. 5mm respectively (total of 5000g) is mixed and poured into the Los Angeles Abrasion machine together with 10 standard steel balls (lack of one from the standard test) and operated for 500 revolutions at 30 – 33 rpm. After that, the sample is sieved through sieve of size 1. 7 mm and the weight retained is weighted. 2. From the test, the weight loss of the 5000g of sample after abrasion is 810g. It translate into a 16. 2% of loss, which is still within the JKR requirement standard (
Narrative Sample Essay
Note: The below essays were not edited by EssayEdge Editors. They appear as they were initially reviewed by admissions officers. SAMPLE ESSAY 1: Brown, achievement: Martial arts competition A faint twinge of excitement floated through my body that night. A hint of anticipation of the coming day could not be suppressed; yet to be overcome with anxiety would not do at all. I arduously forced those ...
