EXPERIMENT 3 DETERMINATION OF SPECIFIC GRAVITY AND WATER ABSORPTION OF AGGREGATES

Transcription

1 COLLEGE OF ENGINEERING AND ARCHITECTURE CIVIL ENGINEERING DEPARTMENT CE405 Construction Materials and Testing 1 st Semester SY EXPERIMENT 3 DETERMINATION OF SPECIFIC GRAVITY AND WATER ABSORPTION OF AGGREGATES Name (SN, FN MI): Section: Group Number: Experiment Performed: Report Submitted: Instructor: Objective(s) The activity aims to introduce the basic principle, significance and procedures in determining the specific gravity and water absorption capacity of aggregates. Intended Learning Outcome(s) The students shall be able to: Familiarize the equipment, apparatus and method in determining the specific gravity and water absorption capacity of aggregates. Determine specific gravity and water absorption capacity of the aggregates. Determine the different state of Specific gravity of aggregates. Background The following are the terminologies needed in the course of this experiment: Absorption the increase in the weight of aggregate due to water in the pores of the material, but not including water adhering to the outside surface of the particles, expressed as a percentage of the dry weight. The aggregate is considered dry when it has been maintained at a temperature of C for sufficient time to remove all uncombined water. Specific gravity the ratio of the mass (or weight in air) of a unit volume of a material to the mass of the same volume of water at stated temperatures. Values are dimensionless. Apparent specific gravity the ratio of the weight in air of a unit volume of the impermeable portion of aggregate at a stated temperature to the weight in air of an equal volume of gas-free distilled water at a stated temperature. Bulk specific gravity (also known as the bulk dry specific gravity) the ratio of the weight in air of a unit volume of aggregate (including the permeable and impermeable voids in the particles, but not including the voids between particles) at a stated temperature to the weight in air of an equal volume of gas-free distilled water at a stated temperature. This is used for computations when the aggregate is dry or assumed to be dry.

2 Bulk specific gravity (SSD) the ratio of the weight in air of a unit volume of aggregate, including the weight of water within the voids filled to the extent achieved by submerging in water for approximately 24 h (but not including the voids between particles) at a stated temperature, compared to the weight in air of an equal volume of gas-free distilled water at a stated temperature. This is used if the aggregate is wet, that is, if its absorption has been satisfied. The items listed above are significant in determination of material properties for testing purposes like for example in concrete mixture computations. This experiment (methods or procedures to be used and done) is based on ASTM Designation C Standard Test Method for Specific Gravity and Absorption of Coarse Aggregate, and ASTM Designation C Standard Test Method for Specific Gravity and Absorption of Fine Aggregate. Resources 1 set of sieves 1 weighing scale 1 scoop or spoon 2 pans ½ bag of fine aggregates ½ bag of coarse aggregates 1 unit oven 1 unit wire basket Procedure Fine Aggregates: 1. Weigh about 250 grams test sample of fine aggregate, W1. 2. Immerse the test sample into a container with water for 24 hours and cover it. 3. Pour excess water carefully to avoid loss of fines. Spread the sample on a flat non-absorbent surface and stir frequently to secure homogenous drying. Continue until the sample approaches a free-flowing condition. The specimen is called saturated surface dry (SSD) when it has reached a surface dry condition. 4. Weigh the SSD sample, W2. 5. Fill the pycnometer with water to the top and weigh, W3. 6. Remove part of the water from the pycnometer, and put the SSD sample into it then fill with additional water to approximately 90 percent of its capacity. And agitate the pycnometer to eliminate all air bubbles. Bring the water level in the pycnometer to its calibrated capacity. 7. Determine the total weight of the pycnometer, specimen, and water, W4. 8. Remove the sample from the pycnometer and dry to constant weight at a temperature of 110 C, cool, and weigh, W5. 9. Calculate the specific gravity and absorption. Note: Bulk Specific Gravity Dry = Bulk Specific Gravity SSD = Apparent Specific Gravity = W 1 W 3 + W 2 - W 4 W 2 W 3 + W 2 - W 4 W 5 W 3 + W 5 - W 4 Water Absorption Capacity = W 2- W 5 x100 W 5

3 Coarse Aggregates: 1. Weigh about 1000 grams test sample of coarse aggregate, W1, with a maximum 25 mm nominal size and should not have particles of size less than 4.75 mm. 2. Soak the aggregates in water at room temperature for a period of 24 hours. 3. Remove the sample from the water. Roll it in a large absorbent cloth until all visible films of water are removed. The sample is now in saturated surface dry (SSD) condition. 4. Weigh the SSD sample, W2. 5. Place the SSD sample in the wire basket and determine the weight in water, W3. Note that the wire basket should be immersed to a depth sufficient to cover it and the test sample during weighing. 6. Remove the sample to constant weight at a temperature of 110 C (approx. 24 hours), and weigh, W4. 7. Calculate specific gravity and absorption. Note: Bulk Specific Gravity Dry = Bulk Specific Gravity SSD = Apparent Specific Gravity = W 1 W 2 - W 3 W 2 W 2 - W 3 W 4 W 4 - W 3 Water Absorption Capacity = W 2- W 4 x100 W 4 Data and Results Fine Aggregates Coarse Aggregates Trial 1 2 Ave. 1 2 Ave. Bulk Specific Gravity Dry Bulk Specific Gravity SSD Apparent Specific Gravity Water Absorption Capacity

4 Analysis Conclusion Recommendation

5 Assessment Criteria Score I. Experiment Conduct The entire Skips more than Skips one or two Performs all the Experimental experiment is not two steps in this step(s) in this steps in the Set-up done at all. experiment. experiment. experiment. Correct Practice Safety Precautions II. Work Habits Time Management Cooperative and Teamwork Neatness and Orderliness III. Report Analysis and Conclusion Does not demonstrate the correct way/s of doing the required steps. Does not follow safety precautions. Not able to finish on time with no data gathered. Has not performed the experiment Messy workplace during and after Does not present any data and result. Provides no analysis and Demonstrates only one or two steps correctly. Follows safety precautions most of the time. Not able to finish on time with incomplete data. Does not know his/her tasks or has no defined responsibility. Group conflicts are not managed well. Messy workplace during the experiment yet clean and orderly workplace after are incomplete and presentation is disorganized. Provides unclear, not logical, unintegrated observation and Demonstrates only some of the required steps correctly. Follows safety precautions most of the time. Finishes on time with incomplete data. Has a defined responsibility most of the time. Group conflicts are cooperatively managed most of the time. Occasional mess during the experiment yet clean and orderly workplace after are well-recorded but presentation is disorganized. but not wellintegrated observation and the experiment based from the data. Demonstrates all the required steps correctly. Follows safety precautions at all times. Finishes ahead of time with complete data and time to revise data. Does the tasks and has a defined responsibility at all times. Group conflicts are cooperatively managed at all times. Clean and orderly workplace at all times during and after the experiment. are well-recorded and wellpresented with complete labels and can be easily understood. and wellintegrated observation and the experiment based from the data.

6 Recommendation Documentation Use of English language Note: Absent during laboratory period and laboratory report/s not submitted on time are both considered as zero (0). Reference Suggests no recommendation. No documentation. Uses English language with many grammatical errors. Provides a recommendation irrelevant to the subject matter. Presents incomplete record of the experiment in photos and video. Uses English language in the explanations made with few grammatical errors. Other Comments/Observations: recommendation relevant to the subject matter. Presents a good record of the experiment in photos and video. Uses good English language in the explanations made. Total Score (Total Score) Rating= 33 recommendation for the betterment of Presents a stepby-step, complete, well-documented experiment in photos and video. Uses the English language proficiently in the explanations made. 100 ASTM Designation C Standard Test Method for Specific Gravity and Absorption of Coarse Aggregate ASTM Designation C Standard Test Method for Specific Gravity and Absorption of Fine Aggregate