道路工程材料(申爱琴版)作业集料水泥(英文版).docx

Assignment forRoad Engineering MaterialsChapter 1 Chapter 2Name：Class：NO. ：SCHOOL OF HIGHWAY COLLEGECHANG’AN UNIVERSITYOCTOBER 31, 2013Chapter one AggregateHere are two kinds of stone, and the test results are shown in following table. Which kind of stone has better performance?Solution: Step 1, the porosity of these two stone can be calculated as the following formula:And the .Step 2, the value saturation-water coefficient of A stone is 0.75, which is higher than the B stone’s, 0.65.Step 3, the higher porosity of stone is, the better water absorption gets and the worse frost resistance is. So is the saturation-water coefficient. From what has been mentioned above, the stone A apparently gets a higherporosity of stone and saturation-water coefficient, so the stone A is worse at frost resistance. Conclusion: stone B has better performance.Please describe the difference between strength indexes of stone and aggregate, and the test methods.Solution:The major strength index for stone isuniaxial compressive strength.The result of measuring uniaxial compressive strength test is represented as resilient modulus with triaxial chamber with external LVDT’s and load cell. And the prepare sample can be cube (in road engineering) or cylinder (in bridge engineering).The major strength index for aggregate is crushing value. And the test method is in the below.Procedure to determine Aggregate Crushing Valuei)The aggregates passing through 12.5mm and retained on 10mm IS Sieve are oven-dried at a temperature of 100 to 110oC for 3 to 4hrs.ii) The cylinder of the apparatus is filled in 3 layers, each layer tamped with 25 strokes of a tamping rod.iii) The weight of aggregates is measured (Weight ‘A’).iv) The surface of the aggregates is then leveled and the plunger inserted. The apparatus is then placed in the compression testing machine and loaded at a uniform rate so as to achieve 40t load in 10 minutes. After this, the load is released.v) The sample is then sieved through a 2.36