Aggregates: Laboratory Tests, The Physical Properties (Lab Report Sample)

Aggregates
Name
Lecturer
Date
Abstract
Aggregates are important material in the construction industry and can be defined as a granular material that is made of sand, crushed stone or gravels. The performance of material which is critical in the construction industry is dependent on the aggregate distribution. The sieve analysis and the void content and density analysis, are some of the methods used in distribution and quality of aggregate analysis. The report base it analysis on an experimental set up in which both void content and density and sieve test analysis is carried out using crashed granite and crushed rock respectively. The sieve analysis is done through passing of the sample aggregate through a set of sieves as shown in table one below. The retained aggregates are weighed and data collected used to fill the table 1 from which a graph of distribution is drawn. A graph of sieve mess size in x-axis (mm), cumulative % passing in the y-axis and cumulative percentage retained in the z-axis was drawn to reflect the aggregate distribution. The percentage difference between the initial sample aggregate and the cumulative sum of the retained aggregate which is 0.11% show that the experiment was successful and the analysis is based on accurate data.
Table of Contents TOC \o "1-3" \h \z \u Introduction PAGEREF _Toc446083380 \h 3Aim and Objectives PAGEREF _Toc446083381 \h 4Apparatus PAGEREF _Toc446083382 \h 4Procedure PAGEREF _Toc446083383 \h 4Experimental Theory PAGEREF _Toc446083384 \h 5Experimental Results and Analysis PAGEREF _Toc446083385 \h 6SIEVE ANALYSIS PAGEREF _Toc446083386 \h 6VOID CONTENT AND DENSITY PAGEREF _Toc446083387 \h 8Discussion PAGEREF _Toc446083388 \h 9Conclusion PAGEREF _Toc446083389 \h 11References PAGEREF _Toc446083390 \h 12Appendices PAGEREF _Toc446083391 \h 12
Introduction
Aggregates are can simply be defines as a granular materials that can either be natural, recycled or manufactured and are mostly used as construction material. Natural aggregates are extracted from large quarry rocks and reduced to the desired sizes through physical crushing. Aggregates can either be from sand, crushed stone and gravels. In construction industry during the preparation of both asphalt concrete and Portland cement concrete, aggregates are mixed together with water, Portland cement and sand. According to (Rogers, 1988) outline natural aggregates as the most abundant natural resource and it compost of crushed stone, sand and gravels. Aggregates are very important constructions, agriculture and industrial metallurgical processes.
The quality of the mixture (concrete) depends on the quality of the input which collectively determines workability and pumpability. Factors such as the size of the aggregates, aggregate void content and the specific gravity of the aggregates affect the choice of aggregate to be used. However, sieve test is very important in determining the gradation or aggregate particle presence within a given mixture.
Aim and Objectives
Aim
* To demonstrate the how laboratory test can be used to assess the physical properties of aggregate intended to be used in concrete.
Objectives
* To understand the grading specification of the aggregates
* To determine sources of flaws in the sieving analysis experiment.
* To understand the importance of the overload check during sieving experiment.
* To demonstrate how variation of density is affected by the type of aggregate used.
Apparatus
* Balance/scale
* Sieves
* Mechanical sieve shaker
* Suitable dry Equipment
* Containers and Utensils
* Optional mechanical washing devices
Procedure
(Sieve analysis process)
* Take a dried oven sample of soil of the desired weight
* Conglomerate the soil particle if they are lumped
* Determine the weight of the soil sample accurately
* Prepare the stuck of sieves with the larger being at the top and smaller size at the bottom.
* Ensure the sieves are clean/ remove any stuck particles
* Weigh all sieves and the pan separately
* Pour the aggregates into the sieves from Top and place the cover, put the stack in the sieve shaker, shake the aggregate for about 10min.
* Stop the sieve shaker and measure the sample of each sieve plus the retained soil.
Experimental Theory
Aggregates normally takes about 70% by volume of the concrete. Aggregates are classified as either manmade or natural and granular materials such as sand, gravel, crushed stone and blast furnace slag are few examples of aggregates. Aggregate analysis is important in concrete analysis because properties such as workability, durability, strength, thermal properties and the concrete density all depend on the quality of the aggregates used.
Aggregates according to (Nmai, Suchorsk & McDowel, 2013) can also be classified into wet, saturated surface dry, air-dry and oven dry depending on the moisture content. The figure below shows the classes of aggregates.
Fig 1: Moisture condition of the aggregates (Nmai, Suchorsk & McDowel, 2013)
Sieve analysis is a test carried out to determine the grain size distribution within a given aggregate range. The test is named sieve analysis dust to the number of sieves arranged from large to small sieve size. The figure below shows an example of sieves.
Fig 2: Sieve arrangement during sieving process
The space between the aggregate that is left unoccupied is normally referred to as void. The percentage of the void in an aggregate is determined using the equation shown below
Experimental Results and Analysis
SIEVE ANALYSIS
Description of the sample Crushed rock
Mass of empty riffle box container, M=151g
Mass of riffle box container + oven dry sample, M=2037g
Mass of the oven dry sample, M= M- M=2037-151=1886 g
Sieve set: B/E
Sieve frame diameter, D: 300 mm
Sieve area, A= (Ï€D/4): 70685.83 mm
Overloading limit, M= (A/d)/200
Sieve mesh size, dn(mm)

serial number of sieve

overload limit for sieve Moverload(g)

Mass of empty sieve(g)

mass of sieve+retained sample(g)

Mass of retained sample Mn(g)

overload check:Moverload>Mn

%of M4 retained on sieve Rn

Cumulative % retained,ΣRn

%finer= 100-ΣRn

BS/EN Limits for grade (%)

pass or fail

14

5791991

1322.41

1103

1103

0

yes

0

0

100

 

 

10

5794662

1117.64

1067

1341

274

yes

14.528

14.528

85.472

 

 

8

5784231

999.64

1122

1698

576

yes

30.54

45.068

54.932

 

 

6.3

5771998

887.1

1157

1750

593

yes

31.442

76.51

23.49

 

 

4

5774862

706.85

1217

1576

359

yes

19.034

95.544

4.456

 

 

2.8

12030593

591.4

1193

1225

32

yes

1.696

97.24

2.76

 

 

2

12030592

499.82

1096

1104

8

yes

0.424

97.664

2.336

 

 

1

12031011

353.429

1204

1207

3

yes

0.159

97.823

2.177

 

 

pan

N/A

 

750

793

43

yes

2.279

100

0

 

 

 

 

 

 

ΣMn

1888

M4

 

 

 

 

 

Table 1: Tabulated experimental values
Mass lost or gained during sieving= (M-M/M) x 100 =…………%
(OK if <0.5%; check arithmetic if >0.5%, and repeat test if error not resolved)
Calculations
%of M4 retained on sieve Rn = (Retained mass/initial oven dry mass)x 100
Case 1= (0/1886) x100=0
Case 2= (274/1886) x100=14.528
Case 3= (576/1886) x100=30.54
Case 4= (593/1886) x100=31.442
Case 5= (359/1886) x100=19.034
Case 6= (32/1886) x100=1.696
Case 7= (8/1886) x100=0.424
Case 8= (3/1886) x100=0.159
Case 9= (43/1886) x100=2.279
Cumulative % retained, ΣRn
Case1= (case o+ case 1) = (0+0)=0
Case1= (case 1+ case 2) = (0+14.528)=14.528
Case1= (case 2+ case 3) = (14.528+30.54) =45.068
Case1= (case 3+ case4) = (45.068+31.442) =76.51
Case1= (case 4+ case 5) = (76.51+19.034) =95.544
Case1= (case 5+ case 6) = (95.544+1.696) =97.24
Case1= (case 6+ case 7) = (97.24+0.424) =97.664
Case1= (case 7+ case 8) = (97.664+0) =97.883
Case1= (case 9+ case 10) = (97.883+2.279) =100
Overloading limit, M= (Ad)/200
Case 1= (70685.83x 14)/200= 1322.41
Case 2= (70685.83x 10)/200 =1117.64
Case 3= (70685.83x 8)/200=999.64
Case 4= (70685.83x 6.3)/200= 887.1
Case 6= (70685.83x 4)/200= 706.85
Case 7= (70685.83x 2.8)/200=591.4
Case 8= (70685.83x 2)/200=499.82
Case 9= (70685.83x 1)/200= 353.429
Mass lost or gained during sieving= (M-M/M) x 100 = (1886-1888/1886) x100= 0.11%
VOID CONTENT AND DENSITY
Description of sample: Large core aggregates/Crushed granite
Volume of empty glass container, V= 3.5 litres
Voids content of sample...