## BUILDING MATERIALS

DETERMINATION OF COMPRESSIVE STRENGTH OF BRICKS

IS: 3495 - Part 1

1. Introduction

This test explains the procedure for the determination of compressive strength of burnt clay building bricks. The dimensions of the test specimens shall be measured to the nearest 1 mm. All apparatus and the testing equipment shall be calibrated at frequent intervals. The number of specimens for the test shall be selected according to IS: 5454-976.

2. Apparatus

A compressive testing machine, the compression plate of which shall have a ball seating in the form of portion of a sphere, the centre of which coincides with the centre of the plate, shall be used.

3. Method for solid bricks

a) Take a sample brick and measure its dimensions. From the dimensions calculate the cross sectional area of the specimens.

b) Remove unevenness observed in the bed faces by grinding, to provide two smooth and parallel faces. c) Immerse the specimen in the water at room temperature for 24 hours.

d) Remove the specimen and drain out any surplus moisture at room temperature.

e) Fill the frog (where provided) and all voids in the bed face flush with cement mortar (1 cement, clean coarse sand of grade 3 mm and down).

f) Store the samples under the damp jute bags for 24 hours followed by immersion in clean water for 3 days.

g) Remove and wipe out any trace of moisture.

3.1 Procedure

a) Place the specimen with flat faces horizontal, and mortar filled face facing upwards between two plywood sheets, each of 3 mm thickness and carefully centred between plates of the testing machine.

b) Apply load axially at a uniform rate of 14 N/mm2 per minute till failure occurs.

c) Note the maximum load at failure. The load at failure shall be maximum load at which the specimen fails to produce any further increase in the indicator reading on the testing machine. NOTE: In place of plywood sheets plaster of paris may be used to ensure a uniform surface for application of load. 3.2 Calculation Compressive strength in N/mm2  =   Maximum load at failure in N            Average area of the bed faces in mm2   Average of results shall be reported.

4. Method for perforated bricks

a) Immerse the specimen in the water at room temperature for 24 hours.

b) Remove the specimen from water and drain out any surplus water.

c) No mortar shall be filled in perforations and no mortar capping shall be provided.

4.1 Procedure

a) Place the perforated faces of the brick specimen between two plywood sheets each of 3 mm thickness and carefully centred between plates of the testing machine.

b) Apply load axially at a uniform rate of 14 N/mm2 per minute till failure occurs. Measure the applied load and note down it.

c) The load at failure shall be maximum load at which the specimen fails to produce any further increase in the indicator reading on the testing machine.

NOTE: In place of plywood sheets plaster of paris may be used to ensure a uniform surface for application of load. 4.2 Calculation Compressive strength in N/mm2  = Maximum load at failure in N (Average net area of the two faces under compression in mm2)   Average of results shall be reported

DETERMINATION OF WATER ABSORPTION OF BUILDING BRICKS
IS: 3495 - Part 2

1. Introduction

This test explains the procedure for determination of water absorption of burnt clay building bricks. The dimensions of the specimen shall be measured to the nearest 1 mm. All apparatus and the testing equipment shall be calibrated at frequent intervals. The number of specimens for the test shall be selected according to IS: 5454-1976.

2.Apparatus

a) A sensitive balance capable of weighing within 0.1% of the mass of the specimen.

b) A properly ventilated oven capable of maintaining temperature 110±5°C.

3. Procedure

a) Remove any dirt adhering to the surface of the brick.

b) Dry the specimen in the oven at 105°C to 115°C till it attains a substantially constant mass.

c) Cool the specimen to room temperature and obtain its weight (M1). d) If specimen is warm, it shall not be weighed.

e) Immerse the dry specimen in clean water at 27±2°C for 24 hours. f) Remove the specimen, wipe out any trace of water with a damp cloth and find the weight (M2).

g) Complete the process of weighing within 3 minutes after removing from water.

4. Calculation

The water absorption after 24 hour immersion in cold water is calculated as below: Water absorption % = (M2-M1)/M1 x 100.

DETERMINATION OF EFFLORESCENCE OF BUILDING BRICKS
IS: 3495 - Part 3

1. Introduction

This test explains the procedure for the determination of efflorescence of burnt clay building bricks. The dimensions of the specimen shall be measured to the nearest 1 mm. All apparatus and the testing equipment shall be calibrated at frequent intervals. The number of specimens for the test shall be selected according to IS: 5454-1976.

2. Apparatus

a) A shallow flat bottom dish with sufficient distilled water to completely saturate the specimens.

b) The dish shall be made of glass, porcelain or glazed stoneware and of size 180 mm x 180 mm x 40 mm. Cylindrical shaped dish shall be 200 mm dia and 40 mm depth.

3. Procedure

a) Place the end of bricks in the dish. The depth of immersion shall be 25 mm.

b) Place the whole arrangement in a warm ventilated room (20°C to 30°C temperature) till all water is absorbed by the specimen and surplus water is evaporated.

c) Cover the dish containing the sample with a proper glass cylinder so that excess evaporation is prevented.

d) When water has been absorbed and bricks appear to be dry, add a similar quantity of water in the dish and allow it to evaporate as before.

e) Examine the bricks for efflorescence after the second evaporation and report the results

f) Using a steel rule or wedge measure the greatest distance of the brick face from the flat surface.

4. Report

The liability to efflorescence shall be reported as 'nil', 'slight', 'moderate', 'heavy' or 'serious' in accordance with the following definitions:

a) Nil - When there is no perceptible deposit of efflorescence.

b) Slight - When not more than 10% of the exposed area of the brick is covered with a thin deposit of salt

c) Moderate - When there is a heavier deposit than under 'slight' and covering up to 50% of the exposed area of the brick surface but unaccompanied by powdering or flaking of the surface.

d) Heavy - When there is a heavy deposit of salts covering 50% or more of the exposed area of the brick surface by unaccompanied by powdering or flaking of the surface.

e) Serious - When there is a heavy deposit of salts accompanied by powdering and/or flaking of the exposed surfaces.

DETERMINATION OF WARPAGE OF BUILDING BRICKS
IS: 3495 - Part 4

1. Introduction

This test explains the procedure for determination of warpage of burnt clay building bricks. The dimensions of the specimen shall be measured to the nearest 1 mm. All apparatus and the testing equipment shall be calibrated at frequent intervals. The number of specimens for the test shall be selected according to IS: 5454-1976.

2. Apparatus

a) A steel rule graduated from one end in 0.5 mm divisions.

b) Alternatively, a steel measuring wedge 60 mm in length,15 mm in width and 15 mm in thickness at one end and tappered, starting at a line 15 mm from one end to zero thickness at  other end. The wedge shall be graduated in 0.5 mm divisions and numbered to show the   thickness of the wedge between the base and the slope.

c) A flat surface of steel or glass, not less than 300 mm x 300 mm in area and plane to 0.02 mm.

3. Procedure

3.1 For measuring Concave warpage

a) Remove any dirt adhering to the surface of the brick

b) Place the flat surface of steel or glass on the surface to be checked.

c) Select the location that gives the greatest departure from straightness.

d) Using a steel rule or wedge measure the greatest distance of the brick face from the flat surface.

3.2 For measuring Convex warpage

a) Remove any dirt adhering to the surface of the brick.

b) Place the brick on the flat surface with the convex face in contact with the flat surface.

c) Measure the distance from flat surface to the four corners of the brick. d) Take the maximum value of the four measurements. 4. Report The highest of the distance obtained in 3.1 and 3.2 is reported as warpage

METHODS OF SAMPLING AND BASIS FOR ACCEPTANCE OF CERAMIC TILE
IS: 13630 - Part 15

1. Introduction

The method for batching, sampling and inspection of unfixed ceramic tiles are explained here. The terms associated with sampling of ceramic tiles are given below:

a) Consignment:A quantity of tiles delivered in two days time

b) Order: A quantity of tiles ordered at a time. It may contain one or more consignments.

c) Inspection lot: A quantity of tiles submitted for inspection. d) Sample: A specified number of tiles taken from an inspection lot. e) Sample size: The number of tiles to be tested for each property.

f) Requirement: A characteristic of the tile specified in the product standard.

g) Non-conforming units: A tile that does not meet the requirement for the specified characteristics.

2. Sampling

a) A complete range of tests shall only be executed for inspection lots of more than 5000 m2 of tiles.

b) Testing is not necessary for inspection lots of less than 1000 m2 of tiles.

c) Two samples shall be taken at random from the inspection lot. It may not be necessary to test the second sample.

d) Each sample shall be packed separately and shall be sealed and marked.

 Sample size Test method asper IS: 13630 10 10 Part 1 30 30 40 40 50 50 60 60 70 70 Part 1 80 80 90 90 100 100 1 m2 1m2 5 5 Part 2 10 10 7 7 Part 6 10 10 5 5 Part 8 11 -- Part 11

NOTE: Determination of Acceptability of Inspection lot and Inspection by average value can be found in IS: 13630 (Part 15) - 2006. e) A guideline to classify the relative importance of each property in relation to the application is explained in Table 2.

Table 2: Properties recommended to be checked for tiles.

 Characteristics Floors Walls Reference to Interior Exterior Interior Exterior part of IS 13630 Dimensions and surface quality Length and width x x x x 1 Thickness x x x x 1 Straightness of sides x x x x 1 Rectangularity x x x x 1 Surface flatness x x x x 1 Surface quality x x x x 1 Physical properties Water absorption x x x x 2 Modulus of rupture x x x x 6 and breaking strength Resistance toabrasion - glazed x x 11 Resistance to x x x x 7 chemicals- glazed

DETERMINATION OF WATER ABSORPTION AND BULK DENSITY
IS: 13630 - Part 2

1. Introduction

Water Absorption of tile can be defined as weight of water absorbed as the percentage of the weight of tile. Bulk density, B, in g/cm3, of a tile is the quotient of its dry mass divided by the exterior volume, including pores.

2. Apparatus

(i) Drying oven capable of operation at about 110°C.

(ii) Heating apparatus made of suitable inert material, in which the boiling will take place

(iii) Balance accurate to 0.01 percent of the mass of a test specimen. (iv) Chamois Leather.

(v) Desiccator. (vi) Wire Loop, Halter, basket capable of supporting specimens under water for making suspended mass measurements.

(vii)  De-ionised or distilled water.

3. Test specimens

(i) A sample for each type of tile under test shall consist of 10 whole tiles.

(ii) If the proper surface area of each individual tile is greater than 0.04 m2, then only 5 whole tiles shall be tested.

(iii) When the mass of each individual tile is below 50 gm, a sufficient number of tiles shall be taken so that each test specimen reaches a mass of 50 gm to 100 gm.

(iv) Tiles with sides larger than 200 mm may be cut up, but all pieces shall be included in the measurement.

(v) With polygonal or shaped tiles, the length and breadth shall be of the enclosing rectangles.

4. Procedure

a) Dry the tiles selected in an oven at a temperature of 110±5°C till they attain constant weight.

b) Cool the tiles in the desiccators over silica gel, until cooled to room temperature.

c) Weigh each tile and record the results (m1) to the corresponding accuracy shown in table 1 below

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