Final Report on comparative study of construction material used in building

Final Project Report On COMPARATIVE STUDY OF CONSTRUCTION MATERIALS FOR BUILDINGS

BACKGROUND: Building material is any material which is used for a construction purpose. Many naturally occurring substances, such as clay, sand, wood and rocks have been used to construct buildings. Apart from naturally occurring materials, many man-made products are in use. The manufacture of building materials is an established industry in many countries and the use of these materials is typically segmented into specific specialty trades, such as carpentry, plumbing, roofing and insulation work. Especially in the modern period, wood and concrete are mainly used as the construction materials. Concrete has been used in Nepal as main construction material in every field and every sector. And talking about the concrete, Concrete is a material used in building construction, consisting of a hard, chemically inert particulate substance, known as an aggregate (usually made from different types of sand and gravel), that is bonded together by cement and water. The Assyrians and Babylonians used clay as the bonding substance or cement. The Egyptians used lime and gypsum cement. In 1756, British engineer, John Smeaton made the first modern concrete (hydraulic cement) by adding pebbles as a coarse aggregate and mixing powered brick into the cement. In 1824, English inventor, Joseph Aspdin invented Portland cement, which has remained the dominant cement used in concrete production. Nepal is rich in the forest resources. And as there is adequate amount of wood it can be used as the construction material which also can overcome the material crisis, which has been seen in the present context of our country. Wood is a product of trees, and sometimes other fibrous plants, used for construction purposes when cut or pressed into lumber and timber, such as boards, planks and similar materials. It is a generic building material and is used in building just about any type of structure in most climates. Wood can be very flexible under loads, keeping strength while bending, and is incredibly strong when compressed vertically. There are many differing qualities to the different types of wood, even among same tree species. This means specific species are better for various uses than others.

Introduction Our project comparative study of construction materials for buildings basically deals with study of various construction materials and their properties. Since the study of construction materials is a vague subject, we limited our project to study the construction materials of Turbine Testing Lab being constructed at Kathmandu University, Dhulikhel and to compare the quality with that of normal residential buildings. The key construction materials are cement, fine aggregates, coarse aggregates, wood, water, bricks, admixtures etc. but our project is mainly concerned with sand, coarse aggregate and bricks. Cement: It is a product obtained by burning a well proportion mixture of siliceous, calcareous and argillaceous materials and crushing the same into fine powder. The cement water paste has its characteristic property of adhesion and cohesion by which it can bond well with aggregates to form a strong mass called concrete, as a consequence of the chemical reaction between cement and water. Aggregates: They are inert materials which when bound together by cement will form concrete. The commonly used aggregates are the naturally occurring aggregates like sand, gravel, and crushed rock. In some cases artificial and processed aggregates are also used to make concrete. Those aggregates which have nominal size of less than 4.75mm are known as fine aggregates. Eg. Sand. And the one whose nominal size is greater than 4.75mm and less than 80mm are termed as coarse aggregate. Brick: Bricks are artificially made rectangular blocks, made from clay. Clay is moulded to form rectangular blocks of standard size, which are dried and later burnt to a high temperature to make them dense and compact. Bricks have become the most essential building components due to their easy availability, good strength, durability and insulating and fire resisting properties. Unlike in stone masonry bricks do not need dressing and the bricks can be laid in a simple process not requiring skilled labour. Bricks are conveniently used in construction of walls, pillars and in some cases floors and roofs.

Rationale of the study: The material of choice of a given era is often its defining point. Phrases such as Stone Age, Bronze Age, and Steel Age are examples of this. Originally deriving from the manufacture of ceramics and its putative derivative metallurgy, materials science is one of the oldest forms of engineering and applied science. Modern materials science evolved directly from metallurgy, which itself evolved from mining and (likely) ceramics and the use of fire.

Thus study of construction materials has been essential for as to understand about the materials. It also helps to make a good decision about the selection of the materials for the construction and the bad aspects can be pointed out which has been used in the society in the construction works. The appropriate dimensions of materials to be used, about the combinations of the materials, study of properties of materials and their features, study about the availability of the construction materials which can help us to minimize the cost, effort and time for a certain project, are some of the necessity of our project.

Objectives of study:. 1. To be familiar with the various types of construction materials, used on different construction sector. 2. To determine the standard of different construction materials applying various testing methods. 3. To compare and contrast the quality of the construction materials used for common residential buildings and those used in high budget project.

Methodology: A. Literature review: We visited library and surfed different sites to be acquainted with construction materials and studied their properties and different testing methods used for determining their qualities.

1. CONCRETE SLUMP TEST In construction and civil engineering, the Concrete slump test (or simply the slump test) is an in situ test or a laboratory test used to determine and measure how hard and consistent a given sample of concrete is before curing. The concrete slump test is, in essence, a method of quality control. For a particular mix, the slump should be consistent. A change in slump height would demonstrate an undesired change in the ratio of the concrete ingredients; the proportions of the ingredients are then adjusted to keep a concrete batch consistent. This homogeneity improves the quality and structural integrity of the cured concrete

Procedure for slump test: 1. The mixing pan was placed on the floor and was moistened with some water. 2. The slump cone was firmly held in place using the 2 foot holds. 3. The bottom one-third of the cone was filled with the concrete mixture was tamped using a hemispherical tip 5/8-inch steel rod in a circular motion.

4. More concrete mixture was added to the two-thirds mark and tamping was repeated. 5. The whole cone was filled up to the top with some excess concrete coming out of top, and then repeated tamping. 6. The excess concrete from the top of the slump cone was removed by striking off the top using the rod in a rolling motion until the concrete surface was flat with the top of the cone. 7. Slowly and carefully the cone was removed by lifting it vertically (5 seconds +/- 2 seconds, and making sure that the concrete sample does not move) 8. We waited for the concrete mixture to slump slowly. 9. After the concrete stabilized, we measured the slump-height by turning the slump cone upside down next to the sample, placing the rod on the slump cone and measuring the distance from the rod to the original displaced center of the slumped concrete. 2. SIEVE ANALYSIS A sieve analysis (or gradation test) is a practice or procedure used (commonly used in civil engineering) to assess the particle size distribution (also called gradation) of a granular material. The size distribution is often of critical importance to the way the material performs in use. A sieve analysis can be performed on any type of non-organic or organic granular materials including sands, crushed rock, clays, granite, feldspars, coal, soil, a wide range of manufactured powders, grain and seeds, down to a minimum size depending on the exact method. Being such a simple technique of particle sizing, it is probably the most common.

3. TESTING OF BRICKS Water absorption test: This is a test to determine the percentage of the water absorption which gi gives an indication of the degree of burning. There are two types of absorption test viz. cold water test and boiling water test. Procedure for cold water test: 1) Dried brick samples were taken and weighed. (W1 was measured) 2) The samples were immersed in clean cold water for 24 hrs. 3) After 24 hrs. again their weights were taken. (W2 was measured) Water absorption percentage = (W2-W1) x 100 W1 Compression test: This is one of the methods to test the compressive strength of the bricks. Procedures: 1) The brick samples were firstly kept under water for 24 hrs. and taken out. 2) After the excess water was wiped out the frog of the brick was filled with cement mortar (1:3) 3) They were kept in a damp place for 24 hrs.

4) They were again immersed in clean water for 5 days. 5) Those samples were air dried, for 7 days. 6) Finally they were placed in compression testing machine between the pressure plates and were gradually until their failure to measure their breaking load.

Compressive strength =

loaded

Max. load at failure Loaded area of the brick

 Site visiting: Visiting the different sites of different scales to about the materials dimensions, quality, quantity, procedure of using those materials etc.  Supervision from the expert: With the guidelines of experts, seniors, and site engineers we will be able to achieve our objective.

 Overviewing the ideas acquired during the research: All the ideas acquired from the research and supervision of the project is overviewed talked and they are managed in guidance of project supervisor.

 Analyzing the completed works and tracing out the final conclusion: All the collected facts and data are analyzed and conclusion is traced out to achieve the final result.

FINDINGS AND ANALYSIS: Slump test: The slump value obtained from the concrete used during slab casting was 50mm. Hence the degree of workability was medium which was suitable for reinforced slab casting. Type of work Road and mass concrete Foundation without reinforcement Foundation of RCC walls footing RCC ordinary slab, beam, etc. Column, thin vertical section and retaining wall

Recommended slump (mm) 25-50 25-75 50-100 50-125 75-125

As listed above, the concrete with obtained slump value can be used for other construction purpose such as road, mass concrete, foundation without reinforcement, foundation of RCC walls footing, beam, etc.

Fig: Slump test result Compression test of concrete cube: Size of cube: 150 mm x 150mm x 150mm Area of the specimen: 22500 mm2 For 14 days compressive strength test Concreting: M-20 Specimen Maximum load applied, N 1 400000 2 430000 3 425000 Characteristics compressive strength (Fck) at 14 days = 18.5 N/mm2

Average load, N 418333.3

Since the compressive strength increases exponentially, the characteristics compressive strength at 28 days would be more than 20 N/mm2.

Sieve Analysis: Sieve size(mm)

Cumulative % retained(wt) 0 0 15 15 71.5 86.5 11.83 98.33 1.5 99.83 Table: result of sieve analysis of coarse aggregates from local area

40 20 10 4.75 base

Sieve size(mm)

% retained(wt)

Cumulative % retained(wt) 0 0 8 8 69.25 97.75 20.5 97.75 1.25 99 Table: result of sieve analysis of aggregates from TTL construction site

40 20 10 4.75 base

% retained(wt)

% passing 100 85 13.5 1.67 0.17 % passing 100 92 22.75 2.25 1

100 90 80 70 60 50 40 30 20 10 0 1.25

2.5

5

10

20

The fineness of coarse aggregates can be comparatively studied with the help of grading curve(refer to graph above). As we can see from the above grading curves that the grading curve corresponding to the aggregates of TTL is steeper than that of residential. This shows that the aggregates of TTL were found to be of better fineness and uniformity. Brick test: Sample 1

Water absorption(% by wt) 2.130

Compressive strength(N/mm2) 12.036

2 3

3.155 2.616

16.050 4.936

Table: analysis of bricks from TTL

Sample 1 2 3

Water absorption(% by wt) 3.621 23.824 4.425

Compressive strength(N/mm2) 11.728 8.333 6.173

Table: analysis of bricks from local area

Figure: placing brick in water for water absorption

figure: compression testing machine

The bricks from both the area have comparatively similar water absorption. However the water absorption percentage of sample 2 from local area was relatively larger even if its strength was nominal because the sample was not uniform in texture and it was not well burnt. The compressive strength of the bricks taken from TTL was relatively greater signifying better quality. Moreover, sample 3 taken from TTL has very low compressive strength even if its water absorption was low. This directly shows that the quality of brick cannot be determined merely from its water absorption and external texture. Lastly we conclude that bricks taken from both areas were of class A.