Define and discuss the following: (a) the terms maximum aggregate size and grading, as used in concrete technology. (b) What considerations control the choice of the maximum aggregate size of aggregate in a concrete? (c) Discuss the reasons why grading limits are specified.

Laboratory specific gravity and absorption tests are run on two coarse aggregate sizes, which have to be blended. The results are as follows: Aggregate A: Buck specific gravity = 2.395; absorption = 4.69% Aggregate B: Buck specific gravity = 2.601; absorption = 0.51% What is the specific gravity of a mixture of 50]% aggregate A and 50% aggregate B by weight?

A field sand cone test is performed on a layer of compacted fill.  determined that the fill soil has a maximum dry unit weight of approximately 120 pcf. Determine the relative compaction of the compacted fill. Unit weight of dry uniform of sand: 95 pcf Weight of sand to fill the cone: 1.10 lb weight of jar + cone + sand (before test): 16.5 lb Weight of jar + cone + sand (after test): 10.5 lb Weight of moist soil excavated from hole: 6.60 lb Moisture content of soil from hole: 10 %

10. A sample of coarse aggregate weighs 1072 g when oven- dried, 1091 g when saturated surface-dried, and 667.6 g when submerged. Calculate the bulk specific gravity, apparent specific gravity, and absorption.

(c) Table 1 shows the mass of fine aggregates used to conduct a specific gravity test. Calculate the; i) Dry bulk specific gravity ii) SSD bulk specific gravity i) Apparent specific gravity iv) Aggregate absorption. Table 1 Mass of Aggregate 600 g SSD Mass of Aggregate 589 g Mass of pycnometer with water 710 g Mass of pycnometer with water and aggregate 1090 g Mass of aggregate at cool temperature 498 g

The following table represents a concrete mixture that has not been completely proportioned. The values given are the theoretical mixture proportions (oven dry basis). Material properties are also provided. Please answer the question at the end of the information given. Theoretical Mixture Proportions (oven dry basis) Water Cement Air Coarse Aggregate ASTM C 150 Type I Cement: Specific Gravity: 3.15 Coarse Aggregate: Well-graded 3/4 in. NMSA rounded gravel Oven-dry specific gravity: 2.63 Absorption: 1.10% Moisture content of stockpile: 3.10 % Oven-dry bulk density: 101.5 lb/ft³ Fine Aggregate: Natural Sand Oven-dry specific gravity: 2.60 Absorption: 3.20% Moisture content of fine stockpile: 3.50% Fineness Modulus: 2.80 265 lb/yd³ 675 lb/yd³ 6.00 % 1816 lb/yd³ What is the theoretical unit weight (in lbs/yd³) of fine aggregate in this concrete mixture (oven dry basis)? Round to the nearest whole number and do not include units when entering your answer.

If needed assume the unit weight of water to be 62.4 lb/ft3 a) A HMAC sample has the following volumetric properties (i) VMA = 0.1865 ft3and (ii)Volume of air = 0.0452 ft3 Compute %VFA.  b) A HMAC sample has 140 lbs of aggregate with a bulk specific gravity of 2.65 and aneffective specific gravity of 2.71. Based on this information the volume of the absorbedasphalt is ________________ft3A compacted sample of hot mix asphalt concrete sample has a unit weight of 135 lb/ft3.c) The sample has an asphalt content of 5% (by weight). Assume no absorbed asphalt.The bulk specific gravity of the aggregate is 2.65, and specific gravity for the asphaltcement is 1.05. Based on this information compute VMA for this mixture.