ANSWER THE FOLLWING QUESTIONS 1 Can absorption capacity be u

ANSWER THE FOLLWING QUESTIONS: 1. Can absorption capacity be used as a measure of the total porosity of an aggregate? 2. What would be the consequence of using oven-dry aggregate in a concrete mix? 3. Why is it more desirable to batch aggregates by weight rather than by volume? 4. Does the fineness modulus completely describe the properties of a fine aggregate? 5. Why is it important to control the amount of material passing the No. 200 sieve? 6. Problem: An aggregate blend of 38% sand and 62% gravel has a unit weight of 3200 lb/yd. Ifthe bulk specif in the blend. fic gravity of the sand is 2.65 and of the gravel is 2.68, calculate the volume percent of void space

Solution

1. In a way, it can be used to find out the porosity of the aggregates, but if the test is not done properly it may give false results. For example, if the aggregates when immersed in water, if doesn\'t get saturated, the results will be faulty.

2. Oven dried aggregates will have completely empty pores, and when they are used in the concrete mix, a considerable amount of the water will be sucked into the pores and therefore the original water cement ratio would get altered(lessened). Therefore the available water for the water cement reaction will get lessened, and therefore a faulty mix will be preapred.

3. It is preferred, because the volume gets changes easily with the variation of temperature and pressure, but the weight remains constant. Also the chemical reactions depend on the weight of the molecules, not on the volume, so it is better to use the weight proportions.