Bulk Density of aggregate

PURPOSE:

To find out the Bulk Density of aggregate (i.e. unit weight and voids in aggregate).

STANDARD: 
ASTM C-29

APPARATUS:

•  Weighing Balance
•  Temping Rod
•  Measuring Cylinder
•  Shovel or stool

SCOPE AND SIGNIFICANCE:

This method is used to determine the bulk density of given specimen during the concrete mix design when the aggregate is to be batched by volume or by weight. Then it is necessary to know the mass of the aggregate that will fill the container of unit volume.

If we know the bulk density of aggregate material than we can easily calculate the mass required to fill a unit volume container.

Bulk Density also indicates the %age of voids present in the aggregate material.

This %age of voids effects the grading of the aggregate which is important in higher strength concrete.

*We will get %age voids by comparing loose state and compacted state.

RELATED THEORY:

Bulk Density:

It is the mass of the unit volume of bulk aggregate material.

The term volume includes the volume of the individual particle and the volume of the voids between the particles.

Bulk density is used in weight and volume batching both.

Absolute Density:

It is the mass per unit volume of individual particles only.

Voids:

It is a space between the individual particles and in a unit volume of the aggregate mass and is not occupied by the solid mineral matters.

*Voids within the particles are not included in the voids for the determination of bulk density by this method

Facts about Bulk Density:

Bulk Density depends upon how densely the aggregate is packed.

It also depends upon the size, distribution and shape of the particles.

If particles are of the same size then it can be packed to a limited extent but when the smaller particles are added, the voids get filled with them and thus the bulk density increases.

For a coarse aggregate a higher bulk density means that there are few voids which are to be filled by the fine aggregate and cement thus the bulk density also depend upon  the degree of packed.

PROCEDURE:

1.     Weigh the empty cylinder
2.     Calculate the volume of the empty cylinder.
3.        Take the weight of cylinder with aggregate.

*The Procedure will be same for fine and coarse aggregate.

OBSERVATIONS AND CALCULATIONS:

Table of observations for Bulk Density

Sample State	Sample Type	Wt. of container	Volume of  container	Wt. of container + wt. of agg.	Wt. of aggregate	Bulk density
		(Kg)	(m3)	(Kg)	(Kg)	(kg/m3)
LOOSE	Fine	5.7	.0035	10.60	4.9	1400
	Coarse	7.45	.0053	15.3	7.85	1481
COMPACTED	Fine	5.7	.0035	11.15	5.45	1557
	Coarse	7.45	.0053	16.20	8.75	1651

    Increase in Bulk Density (Fine aggregate) =    11.21 %

    Increase in Bulk Density (Coarse aggregate) =  11.48 %

COMMENTS:

The bulk density is more in compacted state as compared to the loosewhich shows that the bulk density greatly depends on the degree of compaction or how densely it is packed.            Usually increase in bulk density  should be above 15% for coarse aggregate and should be below 15% for fine aggregate, But in our results it is 11.20% for fine aggregate and 11.48% for coarse aggregate. This deficiency is may be due to not following precautions.

SURVEYING measurements

[ Every Engineer Must Learn By Heart ] 

 The Metric System:

A system of weights and measures which was first adopted by France and is now almost universally used in the sciences and arts. The greater part of the population of the world works on the metric system. The metric is so called because it uses the “meter” as the primary unit.

The SI System of Units:

The International System of units abbreviated as “SI”. From French the SI is accepted in United States and throughout the world. It is a modern version of Metric System of units by the international agreement.

The SI units within the time replaced other systems.

U.S Customary Units:

The U.S customary or British System of Units also called the Foot Pound Second System (FPS) System has been the common system in English speaking countries, although the system within time be replaced by the SI Units (Best for many Years).

Engineers must be able to work in both the SI Units and FPS System of Units.

Basic Quantities and Units:

Quantity	Dimensions	SI Units	FPS Units
Mass	M	Kg	Slug
Length	L	M	ft.
Time	T	sec.	sec.
Force	F	Newton (N)	Pound (lb)

Basic Standards:

The standard relationship between English measures and Metric measures is as follows;

1 inch = 25.4 millimeters = 2.54cm                                  

1 meter = 39.37 inches =1.09 yards

1 liter = 0.22 galls (imp.)

1 gallon (imp.) = 4.546 liters

1 gallon (US) = 3.785 liters

1 Kilogram (kg) = 2.2046 pounds (lb)

Metric Units of Weights/Mass:

1 tonne = 1,000,000 grams = 1000 kilograms

1 quintal = 100,000 grams = 100 kilograms

1 Slug = 14.606 kg

1 Slug = 32.2 lb

Note:

  *The gram is the weight of one cubic centimeter or one millimeter of water.
  *Kilogram is the weight of one liter of water.
  *Tonne is the weight of one cubic meter of water.

Measures of Length:

Following are the basic measures of length in British Units;

12 inches = 1 foot

3 feet = 1 yard

220 yards = 1 furlong

8 fulongs = 1 mile

The measures of lengths in Metric Units are as follows;

1 Kilometer (Km) = 1000 meters

1 meter (m) = 100 centimeters (cm)

1 cm = 10 millimeter (mm)

Metric Units of Liquid Measures:

1 liter = 1000ml

1 liter = 1kg

1 kiloliter (1000 liters) = 1 cu. Meter

Conversion Factors:

1 cu. ft. = 28.317 liters

1 cu. ft. = 0.028 cu. meters

1 cu. ft. = 6.24 galls (imperial)

1 cu. ft. = 7.48 galls (US)

1 imp. gall = 1.20 galls (US), liquid

1 imp. gall = 1.03 galls (US), dry

Indian/Pakistani Measures of Small Weights:

8 ratties = 1 masha

12 mashas = 1 tola = wt.of rupee coin (silver)

5 tolas = 1 chhatak

4 chhataks = 1 pau = 20 tolas

4 pau = 1seer = 80 tolas

10 seers = 1 maund

* 1 masha = 1 gram (approx.)

Measures of Area in Pakistan:

1 Acre = 43560 sq. ft

1 Acre = 4046.46 sq. m

1 Acre = 8 Kanals

1 Kanal = 20 Marlas

1 Marla = 225 sq. ft (* in some regions 272 sq. ft)

1 Marla = 15.50 sq. m

Miscellaneous Conversions Factors:

1 cu.m = 35.32 cu.ft.

1 Pound = 4.448 Newton  (Force)

1 klb = 4.448 kN

1 Psi (lb/sq.in) = 6.689 Pascal (N/sq.m)

1 (lb/sq. ft) = 0.048 (kN/sq.m)