Sample Lab Aggregates

ABSTRACT
The objective of these experiments is to determine specific gravity, absorption capacity, and fineness modulus of a f ine aggregate sample and to plot a gradation curve for the sample. The scope of the experiment was limited to one aggregate sample only. In determining the SSD and oven-dry weights needed for calculation of specific gravities, a conical mold was used to reach an SSD condition and the sample was later dried in an oven. Sieve analysis determined the particle size distribution by sifting the aggregate through a series of eight sieves of different sixes by use of a mechanical shaker. The results found are that the aggregate used has a Bulk Specific Gravity (SSD) of 2.552, which indicates a normal weight, and Absorption of 0.12516%. The fineness modulus is 1.92. These results show that the sample aggregate is fine with a u niform gradation that would not be ideal to use as the sole aggregate for a concrete mixture.

TABLE OF CONTENTS
1.0 INTRODUCTION

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2.0 M ATERIALS

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2.1 Part A - Specific Gravity and Absorption of Aggregate
2.2. Part B - Sieve Analysis

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3.0 E QUIPMENT

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3.1 Part A - Specific Gravity and Absorption of Aggregate
3.2 Part B - Sieve Analysis

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4.0 PROCEDURE

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4.1 Part A - Specific Gravity and Absorption of Aggregate
4.2 Part B - Sieve Analysis

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5.0 RESULTS

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5.1 Part A - Specific Gravity and Absorption of Aggregate
5.2 Part B - Sieve Analysis

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6.0 DISCUSSION

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6.1 Part A -Specific Gravity and Absorption of Aggregate
5.2 Part B - Sieve Analysis

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7.0 CONCLUSIONS
8.0 R EFERENCES
9.0 APPENDIX
A.
B.
C.

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Discussion - Part A, #4 Calculations
Discussion - Part A, #5 Calculations
Lab Handout and Raw Data

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I A,

\0 INTROD

This laboratory was divided into two parts (A & B). Part A looked at the affect water has on the specific gravity and absorption of the m ixture. Part B used sieves to d etermine the r elative size of particles in the aggregate. Specific gravity is the ratio of the mass of a given volume of material to the mass of an equal volume of water. The water c ontent of a concrete mixture can a ffect its strength, durability, and cost. The fineness modulus is an i ndex n umber that is roughly proportional to the average si/e of the particles in a g iven aggregate, w hich a ffects a mixture's gradation. Gradation is the distribution of particle si/c w ithin a given sample of material and affects economy, d urability, workability, and shrinkage in concrete. Understanding the slated objectives is therefore of interest in selecting the best concrete m ixture for a specific construction application to e nsure quality and safety. The objectives of these laboratory experiments are to determine specific gravity (bulk and apparent), absorption capacity, and f ineness modulus of a f ine aggregate sample and to plot a gradation curve for the sample.

2.0 MATERIALS
2.1 Part A - Specific Gravity and Absorption of Aggregate
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Air-dry aggregate ( fine)
Water

2.2. Part B - Sieve Analysis
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Air-dry aggregate (fine)

3.0 EQUIPMENT
3.1 Part A - Specific Gravity and Absorption of Aggregate
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Conical metal mold and lamping rod used for t esting s lump
Balance sensitive to 0.01 grams with maximum capacity -600 grams or more 500 ml plastic v olumetric flask
Metal pan large enough lo hold -400 grams aggregale (specific one used was size of a small bread loaf) Large flai pan to serve as work space
D rying O ven
Vacuum Pump with hose attachment to

3.2 Part B - Sieve Analysis
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Balance sensitive to 0.01 g w ith maximum capacity -600 g rams or more One set of 8 in. d iameter sieves with pan and cover (Figure 1/) •
Mechanical shaker w ith timer (sound enclosure preferred)
S mall brush t o c lean sieves

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Figure 1: Set of 8" diameter,
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sieves

4.0 PROCEDURE
4.1 Part A - Specific Gravity and Absorption...