道路工程材料(申爱琴版)-作业-集料&水泥(英文版)

Assignment for Road Engineering MaterialsChapter 1 & Chapter 2Name：Class ：NO. ：SCHOOL OF HIGHW AY COLLEGECHANG’AN UNIVERSITYOCTOBER 31, 2013Chapter one Aggregate1.Here 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 theB 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 higher porosity of stone and saturation-water coefficient, so the stone A is worse at frost resistance.Conclusion: stone B has better performance.2.Please describe the difference between strength indexes of stone and aggregate,and the test methods.Solution:a)The major strength index for stone is uniaxial compressive strength. The result ofmeasuring uniaxial compressive strength test is represented as resilient moduluswith triaxial chamber with external LVDT’s and load cell. And the prepare sample can be cube (in road engineering) or cylinder (in bridge engineering).b)The major strength index for aggregate is crushing value. And the test method is in thebelow.Procedure to determine Aggregate Crushing Valuei)The aggregates passing through 12.5mm and retained on 10mm IS Sieve are oven-driedat a temperature of 100 to 110o C for 3 to 4hrs.ii) The cylinder of the apparatus is filled in 3 layers, each layer tamped with 25 strokes ofa 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 2.36mm IS Sieve and the fraction passing throughthe sieve is weighed (Weight ‘B’).vi) Two tests should be conducted.Aggregate crushing value = (B/A) x 100%.3.Please describe the classification of aggregate from deferent perspectivesSolution：Solution:Notification: There is some other types of aggregate by different standards●Crashed gravel●Crushed sand●Stone chip●Filler●Slag4.There are two kinds of aggregate, and the test results are shown in followingtable. Please describe the difference of the performance of these two kinds of aggregate.Solution:The lower crushing value is, the better anti-crushing performance aggregate gets. And so is the Los Angeles abrasion ration. So, the aggregate B has a better anti-crushing and anti-crushing and abrasiveness performance.The higher polishing value is, the better anti-slip performance aggregate gets. So, theaggregate A has a better anti-slip performance.5.Please describe the definition, the test and the calculation methods of densitiesof aggregate, and give the rank of different densities.Solution:a) True density:Definition: the mass of a unit volume of the impermeable portion ofmaterial, including the solid and impermeable pore..Test: Le Chatelier flask methodCalculation method:b) Apparent density:Definition: the mass of a unit volume of the impermeable portion ofmaterial, including the solid and impermeable pore.Test: Wire basket methodsCalculation method:c) Bulk density:Definition: the mass of a unit volume of material under natural status,including solid, permeable and impermeable pores.Test: Wire basket methods for coarse aggregateFlask method for fine aggregateCalculation method:d) Stacking density：Definition: dry mass per unit volume of aggregate under some stacking methods.including：Loose density, Tamping density, Compaction density Calculation method:Rank:6.The gradation curves of three kinds of aggregate are show in right Fig. Pleasejudge the gradation categories, and the structure ofasphalt mixture consisted of these aggregateSolution:Gradation A is the gap gradation. One or more intermediateparticle sizes aggregates are missing.Gradation B is the continuous gradation. The particlesdistribute on each sieve size from the large to small.Gradation C is the open gradation. The particles distribute on larger sieve size.7.Discuss the differences between gradation and fineness modulus of fineaggregate Have sand A and sand B, which have the same fineness modulus, the same gradation?Solution:Gradation, the particle sizes and size distribution, refers to the proportion by mass or weight of aggregate particles distributed in special particle-size ranges, not only to individual fine and coarse aggregate , but also to the combined or mixed aggregateFineness modulus, a value which statistically represents the coarse or fine condition of fine aggregate, is statistically determined by the percentage of coarse aggregateSo, the different gradation can have the same fine modulus, and the same fine modulus may not represent the same gradation.Sand A and sand B can have the same the same fineness modulus but not the same gradation.8.Sieving test results of 500g sand are shown in table. Please fill the blank, andcalculate the fineness modulus.sieve size9.5 4.75 2.36 1.18 0.6 0.3 0.15 Pan（mm)mi(g) 0 20 15 40 115 125 155 30ai(g) 0 4 3 8 23 25 31 6Ai(g) 0 4 7 15 38 63 94 100Pi(g) 100 96 93 85 62 37 6 02.052。