Solve the following problems 1. Compute the CBR of the soil sample shown if the sample with the same surcharge imposed upon it is subjected to a penetration by a pinston plungger 1.95 inches in diameter. The CBR value of the standard crushed rock for 0.10 inch penetration is 1000 lb/in² and for the 0,20 inch penetration is 1500 lb/in². Penetration (in) 0.025 0.050 0.075 0.100 0.150 Load (lb) 705 1129 1422 1631 1896 crushed stone (sp.gr. 2.70) sand (sp. gr. 2.65) limestone dust (sp. gr. 2.70) asphalt cement (sp. gr. 1.01) 2. A 53.5 kN wheel load has a maximum pressure of 0.62 MPa. This pressure is to be uniformly distributed over the area of tire contact on the roadway. Assuming the subgrade pressure is not to exceed 0.14 MPa, determine the required thickness of flexible pavement structure, according to the principle of the cone pressure distribution. 3. A plant mix is composed of materials combined in the following proportions by weight 50% 39% Materials Sand Penetration (in) 0.200 0.300 0.400 0.500 Crushed Gravel Limestone Dust Asphalt Cement 5% 6% Load (lb) 2102 2359 The compacted mixture has a bulk sp. gr. of 2.36 after rolling. Determine the porosity of the compacted mixture. 4. An asphaltic concrete is made up the following materials proportion by weight as shown 45% crushed stone (sp. gr. 2.67) sand (sp. gr. 2.70) 44% stone dust (sp. gr. 2.60) 7% asphalt cement (sp. gr. 0.98) 4% Compute the weight of a 50 mm thick suface course in kg/m². 2574 2675 5. From the given data of a particular asphalt concrete pavement mixture, compute the percent voids, if the measured bulk specific gravity is 2.37 Specific Gravity 2.64 2.64 2.82 1.02 Percent of Weight 40.0 44.7 9.0 6.3

Concrete materials are meant for supporting structures, building foundations and they act as several load-bearing structures. Over time, due to environmental conditions, and based on the constituent materials used, concrete materials are subjected to a g…