Variation in workability of concrete by replacing stone

chips with crushed bricks.Submitted by :

Animesh Anand ( BE/10423/12 )Rajeev Ranjan ( BE/10420/12 )

Saurabh Parihar ( BE/10456/12 )

Under the guidance of :Dr. Arun Kumar

ABSTRACT

• By far the most common coarse aggregate used in concrete is obtained from natural rock, but type of rock suitable for concrete making is not available everywhere. • In Tripura a north-eastern state of India brick aggregate concrete are used

conventionally for ordinary concrete due to scarcity of aggregate from natural source. • Due to advancement of concrete technology and to fullfill the durability

requirement it necessitated to use standard concrete, for which only stone aggregate is used, as a result, cost of construction has been skyrocketed as these are transported from other states.

ABSTRACT (Cont.)• Therefore, in this project a concerted effort has been made to check the feasibility of

use of brick aggregate made of locally available brick in standard concrete (M25). • This project describes an experimental investigation on workability of concrete made

of brick chips. • Different sizes of aggregate were used here. It can be seen that pervious concrete

made of brick chips performs well in respect of permeability; however, the strength of this concrete is lower than that of the stone aggregate concrete.

Introduction

• Concrete is produced by mixing cement, sand, coarse aggregate and water to produce a material that can be moulded into almost any shape. The major volume of concrete is filled with aggregate.• The demand for aggregate is enormous in liberalization, privatization and

globalization, and in the construction of important infrastructure projects like Expressways, Airports, nuclear plants etc. The increased extraction of coarse and fine aggregate from the natural resources is required to meet this high demand. The increasing use of natural fine aggregate creates an ecological imbalance. Thus, partial replacement of coarse aggregate is vital in construction industries

Introduction (Contd.)

• Workability of Concrete: Workability is one of the physical parameters of concrete which affects the strength and durability as well as the cost of labor and appearance of the finished product. • Concrete is said to be workable when it is easily placed and compacted

homogeneously i.e without bleeding or Segregation.• Definition of Workability: The property of fresh concrete which is

indicated by the amount of useful internal work required to fully compact the concrete without bleeding or segregation in the finished product.

Material Used• Cement : The cement used was ordinary Portland cement (OPC) of 43 grades conforming

to IS: 8112-1989.• Fine Aggregate : One type of fine aggregate was used throughout the experimental work

so as to keep the fine aggregate variable constant. The sieve analysis was carried out in accordance with IS: 383-1970 for the fine aggregate.

• Brick Aggregate: Full bricks were crushed and then they were passed through 20mm sieve and retained on 10mm sieve. The breaking of brick was done manually with hammer which produced angular aggregate.They were used in SSD (Satutrated Surface Dry) Condition.

• Stone Aggregate: Stone chips passing through 20mm sieve and retained on 10mm sieve were used throughout the project.

• Water: Water available in the college laboratory

Measurement of workability: Slump Test

• The slump is a measure indicating the consistency or workability of cement concrete. It gives an idea of water content needed for concrete to be used for different works. • Apparatus: Iron pan to mix concrete, slump cone, trowels,

tamping rod and graduated cylinder.

Apparatus

Standard Slump Values

Degree of workability Slump (mm) Use for which concrete is suitable

Very low 0-25 Very dry mixes; used in road making. Roads vibrated by power operated machines.

Low 25-50Low workability mixes; used for foundations with light reinforcement. Roads vibrated by hand operated Machines.

Medium 50-100Medium workability mixes; manually compacted flat slabs using crushed aggregates. Normal reinforced concrete manually compacted and heavily reinforced sections with vibrations.

High 100-175High workability concrete; for sections with congested reinforcement. Not normally suitable for vibration

Preparation Of Sample

• Sand : Cement : Coarse Aggregate – 1:1:2• Maximum Cement Content : 420KG/m3

• Brick Bats are used in SSD condition.• Water Used

Sl. No.

Water Cement Ratio

Volume of Water (Litres)

1. 0.4 22. 0.45 2.253. 0.5 2.5

ObservationsValue Of Slump (mm)

Sl.No. Stone Chips : Brick Bats W/C ratio

0.4 0.45 0.51. 1 : 0 80.3 101 1042. 3 : 1 78.1 97 1023. 1 : 1 61 83.7 89.84. 1 : 3 43.3 67 73.25. 0 : 1 34 47 58.4

Table 1.0

Low WorkabilityMedium WorkabilityHigh Workability

Slump Values

Sl No W/C Ratio

Stone Chips : Brick Bats

1 : 0 3 : 1 1 : 1 1 : 3 0 : 1

1. 0.4 80.3 78.1 61 43.3 34

2. 0.45 101 97 83.7 67 47

3. 0.5 104 102 89.8 73.2 58.4

Table 2.0

Observations (Contd.)

0% 25% 50% 75% 100%0

20

40

60

80

100

120Slump Value (mm) vs Brick bats (%)

W/C : 0.4 W/C : 0.45 W/C : 0.5

Figure 1.0

Result• The Variation in workability of concrete by varying percentage

of brick bats as coarse aggregate with W/C ratio as 0.4, 0.45 and 0.5 are given in table 1 and table 2. Also Corresponding graph was plotted in figure 1.

Conclusion

• The use of fresh brick and waste brick as a coarse aggregate in concrete mixes is a feasible option.• Crushed bricks can be used satisfactorily to produce M25

concrete keeping water cement ratio in the range of 0.4 to 0.50.• Again where availability of natural aggregate is limited brick

aggregate, which can be obtain easily by crushing bricks made from landfills, can safely, be used as a viable alternative in making concrete.

Future Scope

• Large scale exploitation of natural aggregate and expensive transportation cost, it has become necessary to find any other alternative of natural aggregate . Replacement of natural aggregate will not only save the natural sources for future generation but will also prevent the environment by using waste material as natural aggregate.