Material Testing

Testing of Concrete Blocks

INTRODUCTION
Concrete can be converted into precast masonry units such as Hollow and Solid normal and light weight concrete blocks of suitable size to be used for load and non-load bearing units for wallings. Use of such concrete blocks are more appropriate in region where soil bricks are costly, poor in strength and are not available. Depending upon the structural requirements of masonry unit, concrete mixes can be designed using ingredients available locally or if not found suitable then with in the most economical distance. The concrete mix used for normal hollow and solid blocks shall not be richer than one part by volume of cement to 6 parts by volume of combined room dry aggregates before mixing. Hollow concrete blocks for normal work used in masonry when reinforced is used shall not be leaner than 1 part cement to 8 parts room dry sand by volume. The mixes are designed with the available materials to give overall economy and the required properties of the products. The hollow load bearing concrete blocks of the standard size 400 x 200 x 200 mm will weight between 17 and 26 kg (1063 to 1625 kg/m3) when made with normal weight aggregates. Normal weight blocks are made with cement, sand, gravel, crushed stone and air-cooled slag. The grading for sand used in Hollow concrete block shall be as given below:

I.S. Sieve Size	Percentage Passing
4.75 mm	98-100
2.36 mm	80-100
1.18 mm	60-80
600 Micron	40-65
300 Micron	10-40
150 Micron	0-10

The aggregates for solid blocks shall be sand as per IS : 383-1970 and well graded aggregate of suitable maximum size as per the dimensions of the block. The mixes are properly designed as per standard practice. Concrete admixtures may be used in both Hollow and Solid concrete blocks.
SPECIMENS
20 full size units shall be measured for length, width and height. Cored units shall also be measured for minimum thickness of face, shells and webs. From these 3 blocks are to be tested for block density, 8 blocks for compressive strength, 3 blocks for water absorption and 3 blocks for drying shrinkage and moisture movement.
DETERMINATION OF BLOCK DENSITY
Three blocks shall be dried to constant mass in a suitable oven heated to approximately 1000C. After cooling the blocks to room temperature, the dimensions of each block shall be measured in centimeters to the nearest millimeter and the overall volume computed in cubic centimeters. The blocks shall then be weighted in kilograms to the nearest 10 gm. The density of each block calculated as follows:
Density in kg/m³ = Mass of block in kg/Mass of block in cm² * 10⁶
DETERMINATION OF WATER ABSORPTION
Three full size blocks shall be completely immersed in clean water at room temperature for 24 hours. The blocks shall then be removed from the water and allowed to drain for one minute by placing them on a 10 mm or coarser wire mesh, visible surface water being removed with a damp cloth, the saturated and surface dry blocks immediately weighed. After weighing all blocks shall be dried in a ventilated oven at 100 to 1150C for not less than 24 hours and until two successive weighing at intervals of 2 hours show an increment of loss not greater than 0.2 percent of the last previously determined mass of the specimen. The water absorption calculates as given below:
Absorption, percent =(A-B)/B * 100
Where,
A = wet mass of unit in kg.
B = dry mass of unit in kg.
TESTING BLOCKS FOR COMPRESSIVE STRENGTH
COMPRESSIN TESTING MACHINE (CTM)
The compression testing machine should be as per IS : 516-1959 and I.S : 14858-2000. The load capacity, platens sizes, vertical space between platens and horizontal space between machine columns shall be as per the requirements of the specimens to be tested.
However, IS : 2185 (pert-I) – 1979 specified that when the bearing area of the steel blocks is not sufficient to cover the bearings area of the blocks, steel bearing plates shall be placed between the bearing blocks and the capped specimen after the centroid of the masonry bearing surface has been aligned with the centre of thrust of the bearing blocks. It is desirable that the bearing faces of blocks and plates used for compression testing of concrete masonry have hardness of not less than 60 (HRC).
When steel plates are employed between the steel bearing blocks and the masonry specimen, the plates shall have thickness equal to at least one-third of the distance from the edge of the bearing block to the most distant corner of the specimen. In no case shall the plate thickness be less than 12 mm.
ASTM : C 140-03 specified that when the bearing area of the upper platen or lower platen is not sufficient to cover the area of the specimen, a single steel bearing plate with a thickness equal to at least the distance from the edge of the platen to the most distant corner of the specimen shall be placed between the platen and the capped specimen. The length and width of the steel plate shall be at least 6.3 mm grater than the length and width of the unit. The surface of the platen or plate hardness shall be not less than HRC 60 (BHN 620).
Thickness of bearing plates has a significant effect on the tested compressive strength of masonry units when the bearing area of the platen is not sufficient to cover the area of the specimen. Tested compressive strength will typically increase with increased plate thickness and with reduce distance to the further corner of the specimen. Accordingly the CTM platens shall have the required dimensions with respect to the specimens to be tested on it.
TEST SPECIMENS
Eight full size units shall be tested with in 72 hours after delivery to the laboratory, during which time they shall be stored continuously in normal room air.
For the purpose of acceptance, age of testing the specimens shall be 28 days. The age shall be reckoned from the time of the addition of water to the dry ingredients.
CAPPING TEST SPECIMENS
The bearing surfaces of units shall be capped by gypsem. The gypsem and water paste shall be spread evenly on a non-absorbent surface that has been lightly coated with oil. The surface of the unit to be capped shall be brought into contact with the capping paste. The average thickness of the cap shall be not more than 3 mm. The caps shall be aged for at least 2 hours before the specimens are tested.
PROCEDURE
Specimens shall be tested with the centroid of their bearing surfaces aligned vertically with the centre of thrust of the spherically seated steel bearing blocks of the testing machine.
The load up to one-half of the expected maximum load may be applied at any convenient rate, after which the control of the machine shall be adjusted as required to give a uniform rate of travel of the moving head such that the remaining load is applied in not less than one nor more than two minutes.
The compressive strength of a concrete masonry unit shall be taken as the maximum load in Newtones divided by the gross cross sectional area of the unit in square millimeters. Report to the nearest 0.1 N/mm2 separately for each unit and the average for the 8 full units.
Note:- The Gross area is : The total area occupied by a block on its bedding face, including areas of the cavities and end recesses.
REFERENCES
1.IS : 2185 (part-I)1979 1987 1998 – Specifications for concrete masonry. Units part-I  Hollow and Solid Concrete Blocks (Second Revision).
2. IS : 2185 (part-II)- 1985
Super seeding IS : 3590-1966 Specifications for concrete masonry units part-II Hollow and Solid light weight concrete blocks (First Revision)
3. IS : 2572-1963 Reaffirmed 1997  Code of practice for construction of hollow concrete block masonry.
4. IS : 383-1970 Specification for coarse and fine aggregates from natural sources for concrete (Second Revision)
5. ASTM : C 140-03  Standard test methods for sampling and testing concrete masonry units and related units.

Simple Testing Of Admixtures And Surface Coating For Permeability To Water.

This method of test describes the procedures for determining concrete permeability to water by capillary absorption method for comparison between controlled specimens and the specimens containing admixtures having surface coatings. This method gives the waterproofing efficiency of admixtures and coating, thus also of the greatest interest for durability of concrete offers protection to reinforcement from corrosion.
For all test specimens materials, proportions, workability, mixing, compaction, casting, curing, temperature and testing method should be kept identical for conclusive comparison between controlled and admixture/coated specimens.
Casting of Specimens
10cm cubes of the following mix are to be cast by hand compaction filling the cubes in two layers each layer to be rammed 35 times by ramming rod 16mm dia 600mm in length one end bullet pointed. A set of 3 cubes shall be prepared with the recommended dosage of admixture. The other set of 3 cubes shall be made without any admixture (controlled cube). In case of surface coating is to be tested, then all the six cubes shall be made of the same mix.
Mix Proportions
OP Cement 43 grade = 200 Kg/m³
Sand Zone II = 850Kg/m³
20-5mm aggregate = 1115lg/m³
Water= To give slump of 40⁺_-5mm or compaction factor of about 0.90.
The above is a suggested mix of sand and aggregate having specific gravity of 2.6. Mixes may be designed as per local aggregates.
Cement:Aggregate ratio should be kept 1:9 to 1:10
Liquid admixtures usually reduce the water demand, but in very lean mixes there shall not be much reduction in mixing water.
The water of the liquid admixture should be accounted in the mixing water. A few trials of controlled concrete workability will be required for getting the exact quantity of mixing water for obtaining required workability. As far as possible this controlled concrete mixing water should not be exceeded with the admixture mix. The lean mix as recommended above will be desirable for this type of test.
Procedure of Testing
After 24 hours of casting, all the cubes shall be demoulded and cured in clean water in the same curing tank for 28 days. After 28 days of curing all the cubes shall be dried in a ventilated oven at the temperature of 100^oC to ⁺_-10^oC till constant weight. If surface coating is to be tested, then as per recommendations of the manufacturer three cubes to be surface coated at one face and upto the height of 5 cm on all the four faces. After coating and conditioning, these cubes along with the controlled cubes shall again be died in the oven at a temperature of 50^oC to ⁺_-2^oC till constant weight. Coated cubes faces should be kept upward while keeping them in oven, sot that coating should not be damaged. The coating after its application should withstand without any physical and chemical change a temperature of 50^oC, which is a temperature normally reached of concrete surfaces exposed to sun at most places of India during summer. A coating sensitive to this temperature should not be tested with this method.
All the six weighted cubes shall be placed in the same glazed or glass flat tray, so that the cubes are dipped up to a level of 1.2cm. The level of the water shall be maintained throughout the experiment by adding fresh water from time to time. Evaporation of water from exposed cubes surfaces and tray is prevented by covering the entire set up by polythene. Care should be taken that polythene should not disturb the set up. Determine the gain in weight of the cube at different intervals till the weight of cube become constant.
The permeability of each cube of a set shall be found by determining the coefficient of water absorption with the help of the formula:
A= M_w/t
Where A – Coefficient of water absorption.
M_w – Amount of water absorbed per unit area.
T – Time in second for absorption
From the test results the effectiveness of admixtures and coating may be compared with controlled specimens. This method is simple for testing waterproofing admixtures and coating without any special equipment.
This paper by Er. Kaushal Kishore was first published in NBM&CW magazine.

Filed under

Setting Up Small Testing Laboratory at Field

Designers and builders of construction projects no longer can consider quality control testing an option or convenience. In the past decade, testing for the quality of materials and finished construction has become a necessity that no responsible builder can neglect.
The truth of this statement is proved not only by construction delays and cost overruns but also by catastrophic failures of major structures. Such catastrophies include dam failures, collapses and foundation breakdowns in multi-storeyed office and apartment structures; and other failures in stadia, factories, schools, auditoria, public buildings and bridges.
Each construction project determines its own individualized testing needs. A variety of factors influence the type of testing required. Among these factors are size of the structures, terrain, type of soil and subsurface conditions at the construction site and other conditions peculiar to the specific location. The expertise of the construction engineers and technical personnel working on the project will also have an influence on the testing and inspection need.
Testing facilities may range from a simple, inexpensive test kit carried in a portable chest to a fully equipped Central Testing Laboratory.
A small Field Testing Laboratory, which can perform all the required tests can be set up at any construction site with a small investment of about Rs. 71,300/-. The equipments of the Laboratory shall be as given below:

S. No.	Items	Qty	Approx. Cost (in Rs.)
1	Hydraulic Compression Testing Mechine, hand operated 100 tonnes capacity. Conform to the requirements of IS: 516-1959, IS :14858-2000 caliberated to an accuracy of ± 1% indicated load within range.	1 No.	20,000
2	Cube moulds 150×150x150 mm size conforming to IS : 516-1959, IS : 10086-1982.	12 Nos.	5,000
3	Slump apparatus conforming to IS: 7320.	1 No.	1,000
4	Test sieve set IS : 460-1972, 30 cm dia frame of size 40mm, 20mm, 12.5mm and 10 mm and 20 cm dia frame of size 4.75mm, 3.35 mm, 2.36mm, 1.18mm, 600 micron, 300 micron, 150 micron, 90 micron and 75 micron.	One Set	5,000
5	Bulk density measure 3 and 15 litres capacity as per IS : 2386 (Part-III)- 1963.	One Each	2,000
6	Thickness and length gauge as per IS : 2386 (Part-I)- 1963.	One Each	800
7	15 cm dia aggregate crushing value apparatus as per IS : 2386 (Part-IV)- 1963.	1 No.	1,000
8	Graduated cylinder of glass 100, 250 and 1000 ml capacity.	3 Nos. each	300
9	Balances 1 kg, 5kg and 15 kg capacity.	One each	6,000
10	Electric oven, thermostatically controlled upto 2000C, chamber space about 40×40x40 cm.	1 No.	4,000
11	Concrete Test Hammer (rebound hammer) of impact energy 2.207 N.m (0.225 Kgm) as per IS : 1331 (Part-2)- 1992.	1 No.	5,000
12	Flat edge 10 cm dia glass cylinder with glass plate 2000 ml capacity.	1 No.	200
13	Miscellaneous items such as mixing trays, rice trays, karni etc.	One Set	2,000
14	Le-chatelier apparatus as per IS : 4031.	2 Nos.	500
15	Vicat apparatus as per IS : 4031	1 No.	1,000
16	Vibration machine with 6 moulds as per IS : 4031.	1 No.	10,000
17	Hot Plate	1 No.	2,000
18	Apparatus (HCl heat of solution method) for estimation of cement content of fresh concrete.	1 No.	500
19	Chemicals for water content determination of fresh concrete sodium chloride, nitric acid, nitrobenzene, ferric alum, silvernitrate, potassium thipcyanate, sodium hydroxide and HCl.	For 50 tests	3,000
20	Glass ware for testing of S.No. 19	One Set	2,000
		Total	Rs. 71,300

With the above equipments, the following testing of construction materials can be conducted:-

1. TESTING OF COARSE AND FINE AGGREGATE:
a) Sieve analysis as per IS : 2386 (Part-I)- 1963.
b) Deleterious materials as per IS: 2386 (Part-II) – 1963.
c) Specific gravity, density, voids and absorption as per IS: 2386 (Part-III) – 1963.
d) Soundness as per IS: 2386 (Part-V) – 1963.
2. TESTING OF COARSE AGGREGATE:
a) Aggregate crushing value as per IS: 2386 (Part-IV) – 1963.
b) Elongation and flakiness index as per IS: 2386 (Part-I) – 1963.
3. TESTING OF FINE AGGREGATE:
a) Silt content as per IS: 2386 (Part-I) – 1963.
b) Material finer than 75 micron as per IS: 2386 (Part-I) – 1963.
c) Organic impurities as per IS: 2386 (Part-II) – 1963.
d) Bulking as per IS: 2386 (Part-III) – 1963.
4. TESTING OF CEMENT AS PER IS: 4031:
a) Fineness of cement by dry sieving.
b) Determination of soundness by le-chatelier method.
c) Determination of consistency and setting time.
d) Determination of compressive strength.

5. CONCRETE MIX DESIGN
6. TESTING OF FRESH CONCRETE:
a) Test for workability as per IS : 1199-1959.
b) Determination of density, yield, cement factor and air content as per IS : 1199-1959.
c) Casting of cubes as per IS : 516-1959.
d) Test for cement content of fresh concrete.
e) Test for water/cement ratio and concrete 28 days compressive strength in 15 minutes of any grade of cement, so that any concrete batch discharged from the mixer found sub-standard should not be allowed for placing.

7. TESTING OF HARDENED CONCRETE:
a) Compressive strength as per IS : 516-1959.
b) Density.
c) Non-destructive testing of concrete structures as per IS: 13311 (Part-II)- 1992.
8. TESTING OF CONCRETE ADMIXTURES AS PER IS: 2645 AND IS: 9103.
a) Workability test.
b) Permeability test by capillary absorption method
c) Setting time
d) Compressive strength
e) Bleeding.
9. TESTING OF BRICKS:
a) Compressive strength as per IS: 3495 (Part-I) – 1976.
b) Water absorption as per IS: 3495 (Part-II) – 1976.
c) Efflorescence as per IS: 3495 (Part-III) – 1976.
10. TESTING OF TARFELT AS PER IS: 1322 – 1982.
a) Pliability test
b) Storage sticking test
c) Heat resistance test
d) Water absorption test.
11.TESTING OF GLAZED TILES AS PER IS: 777- 1970.
a) Impact strength test
b) Water absorption test
12. TESTING OF MARBLE AS PER IS: 1124-1974
a) Water absorption test
b) Specific gravity test
13. TESTING OF WOOD AS PER IS: 287-1973
a) Compressive strength
b) Moisture content
c) Density
14. TESTING OF FLUSH DOOR SHUTTER
a) Knife test as per IS: 1659-1969.
b) Glue adhesion test as per IS: 2202 (Part-I) – 1973
c) End Immersion Test.
The above laboratory can be set up at any construction site in a small covered area of about 16 sq. meter with small investment of only Rs. 71,300/- which can perform tests on almost all construction materials including quality control of fresh concrete, testing of hardened and non-destructive testing of concrete structures. However, such laboratory must have well experienced persons to run it properly. A person may be trained in 15 days time for conducting all the above mentioned tests.
REFERENCES:
1. Dr. C.B. Kukreja, Kaushal Kishore, Dr. S.K. Kaushik, V.K. Gupta, “Materials Testing Laboratory Manual”, Standard Publishers Distributors, 1705-B, Nai Sarak, Delhi-110 006
2. Kishore Kaushal, “Concrete Mix Design Based on IS: 456-2000” Standard Publishers Distributors, 1705-B, Nai Sarak, Delhi-110 006
3. Kishore Kaushal, “Non-Destructive Testing of Concrete”, Builders Friend, Lucknow, Feb. 1982, pp. 3-4
4. Kishore Kaushal, “Testing Hadened Concrete by Surface Hardness” Indian Concrete Institute Bulletin, Sep. 1987, pp. 17-22.
5. Kishore Kaushal, “Concrete Cube Testing- is Performed Assured” Civil Engineering and Construction Review, New Delhi, Jan. 1990, pp. 23-24.
6. Kishore Kaushal, “Concrete Cube Testing”, Bulletin of Indian Concrete Institute, No. 51, Apr-Jun. 1995.
7. Kishore Kaushal, “Concrete Cube Testing”, Civil Engineering & Construction, Apr. 1995, pp. 33.
8. Kishore Kaushal, “ Evaluation of Cracks in concrete Structures”, Civil Engineering & Construction May. 96, pp. 46-51.
9. Kishore Kaushal, “Simple Testing of Admixtures & Surface Coatings for Permeability to Water”, NBM & CW Feb. 2000.
10. Kishore Kaushal, “28-days Strength of Concrete in 15 Minutes”, Civil Engineering and Construction, Aug. 1992, pp. 38-41
11. Kishore Kaushal, “Testing Concrete For Cement Content Water Content And Ph Value”, Civil Engineering & Construction, Apr. 2008, pp. 54-59.
We at engineeringcivil.com are grateful to Sir Kaushal Kishore for submitting this very useful field test information to us.

Various Lab Test On Soil

Soil inspection or say geotechnical inspection is very important in understanding the physical properties of soil and the rocks beneath. This is required to ascertain the the type of foundation required for the proposed construction. Various tests are done to explore the sub surface and surface characteristics of soil .Some of these are given below.
Just click on the link to go to the details of that particular test
1) Water Content – There are two test which can be done to determine the water content of soil. These are
a) Calcium Carbide Method
b) Oven Drying Method
Other tests on soil are :
2) Free Swell Index Of Soil
3) Plastic Limit Of Soil
4) Liquid Limit Of Soil
5) Particle Size Distribution Of Soil
6) The Specific Gravity Of Soil
7) The In-Situ Dry Density Of Soil By Sand Replacement Method
8 ) The In-Situ Dry Density Of Soil By Core Cutter Method
9) The Maximum Dry Density And The Optimum Moisture Content Of Soil
Apart from these some Soil Compaction Tests are also done. See this for details

Various Lab Test On Bitumen

Bitumen is a mixture of organic liquids that is black, highly viscous, sticky product used for paving roads, waterproofing products (used in sealing roofs). There are many tests which are conducted to check the quality of bitumen. Bitumen is very important component of many construction sites like roads, highways. Many tests are done to ensure the quality of bitumen. Some of these are given below :-

1. Bitumen Content
2. Ductility Of Bitumen
3. Penetration of Bitumen
4. Specific Gravity of Bitumen
5. Softening Point Of Bitumen
6. Flash And Fire Point Of Bitumen
7. The Marshall Stability of Bituminous Mixture