Literature Review on IS Code 5454-1978
This blog contains the literature review of IS code 5454-1978
CONTENT
This paper contains the review based on IS code 5454 - 1978 which is “Method of sampling of clay building bricks”. It contains the information of quality of bricks that helps in construction of buildings and it contains the sampling procedures which help in evaluation of quality of bricks & sampling procedures for transverse strength, breaking load and bulk density is also being included in this review paper. It also explains how to collect samples from a Lot of bricks and we can test that bricks further and then we can make decision about the acceptance or rejection of the bricks. And it contains the literature review in which we have explained all the procedure of conducting the tests and selection of bricks from a lot or from a lorries or trucks and also about the dimensional characteristics. At last it contains the conclusion in which it has been explained what are the test results got from the experiment and then in literature review there is detailed explanation of the IS 5454-1978.
ABSTRACT
First point in this review paper is that to find the non-destructive fast method to find mechanical properties of the masonry or bricks. Dodge and Romig are the two who popularized the acceptance sampling. Sample must be chosen randomly from a lot and also on the based on information yielded by the sample. However, the decision must be one either to accept the lot or to discard it hence this is known as Lot acceptance sampling. It will be just like we should take only one decision either we have done no inspection or 100% inspection. Here the main purpose of lot acceptance sampling is that to choose whether lot is acceptable or not but not to estimate the quality of the lot.
INTRODUCTION
A lot must be accepted based on the number of defective pieces and then to make decision whether to accept or to reject the lot or we can take the other sample and then the process of making decision may be repeated. There are different types of sampling plans such as single sampling plan, double and multiple sampling plan. As bricks are most widely used material in the construction work by doing the various tests on the bricks will helps us to build a building without any defective there this method has been adopted for evaluation of the brick
LITERATURE REVIEW
- · Sampling in motion
- · Sampling in stack
- · Sampling from Lorries or Trucks
· Inspection of visual and dimensional characteristics
· Inspection for physical characteristic
Sampling in motion: some samples of bricks shall be taken when bricks are being moved as in case of loading or unloading at the regular intervals so as to get true representation of the whole quantity.
Lot arranged will be divided into the portions. In all lots almost equal number of bricks are being kept so that while selecting brick for testing it will be easy & fast.
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Sampling in stack: When sample needs to be taken from a stack. It can be divided into number of the sections and then the number of bricks are taken from each section. And the bricks in the upper layer are removed and then samples are taken within the stacks.
The number of bricks necessary for the tests should not be more than 15,000
units for the machine made bricks and 5000 units for handmade bricks. Bricks should be arranged in random so that the sample required get equal chance to be chosen from each stacks including the bricks that are inside the stacks. There may be also possible of removing the bricks from upper layer to get the bricks that are inside the stacks. If the stacks are large it will become difficult to choose the sample in case stack is small, then it will be easy.
Sampling from Lorries or Trucks – In this type of sampling sample is taken from the lorries or trucks loaded in them. Equal number of bricks are taken from each lorries or trucks for testing purpose.
It is impossible or impractical of testing bricks one by one each so sampling method is followed for proper and better testing of quality of bricks. The main idea here is to divide the whole lot onto 10 number of imaginary or real sections and in them taking the required sample.
SCALE OF SAMPLING CRITERIA FOR CONFORMITY OF VISUAL AND DIMENSIONAL CHARACTERISTICS
The bricks must be chosen and evaluated for each lot separately for getting required brick with good specifications. A lot with number of bricks to be selected will be depending on the size of lot. If there are 2000 to 10000 bricks in lot, then the number of bricks to be selected are 20 in same way remaining should be selected that are specified in the Table-1 and also the possible number of defectives are also being specified in the Table. If the dimensions are specified sample brick should be selected from group of 20 bricks that are specified in column1 & 4 in Table-1. If there are less than the 2000 bricks in a lot then sampling must be an agreement between the supplier and purchaser.
VISUAL CHARACTERISTIC
For visual characteristic column 1& 2 need to be observed. Then if the defective bricks are got as per the number specified in column-3 or even less then it can be considered that lot satisfies the visual characteristics requirements. If we get the more number of defective bricks then that lot will not satisfy the needed requirements and some other bricks can be rechecked or whole lot is discarded.
DIMENSIONAL CHARACTERISTIC
We can see that in various standards for clay building bricks the tolerances and dimensions have been specified and in some dimensions and tolerances have been specified for the single brick. In some other standards the dimensions and tolerances is specified for 20 bricks.
It will be considered as visual characteristics if the dimensions and tolerances is just specified for the single bricks. In case of 20 bricks selection of bricks will be according to column 1 & 2. Bricks are divided into a group of 20 bricks randomly and test is carried out for dimension and tolerance.
SCALE OF SAMPLING AND CRITERIA FOR CONFORMITY FOR PHYSICAL CHARACTERISTICS
Next process is to check the physical properties such as the breaking load, transverse strength, compressive strength, water absorption & bulk density etc. for the lot which is found satisfactory in dimensional and visual characteristics. Bricks are selected randomly from the group of the already chosen bricks. Then they are tested for all those characteristics
And after completion of testing for the transverse, compressive strength and breaking load the average is taken or calculated and the values obtained must satisfy the specifications mention in the Table-2.
If the values got exceeds the upper limit for the class of the bricks then it will be limited to the upper limit for the averaging
The compressive strength for the single bricks should not be less than the average minimum compressive strength as per the specifications mentioned & specified for the class of bricks more than 20%. After getting the average values from the test results are collected and all shall satisfy the required specifications as mentioned. And the number of bricks that fails to satisfy the efflorescence requirements that are specified should not be more than the number of defectives mentioned in column 3 in the Table-2. And also the bricks that fails to satisfy the warpage requirements that are mentioned in Table-2 column 5 should not be more than number of defectives as shown.
ADVANTAGES OF CARRYING OUT SAMPLING PROCEDURE
· It will help to reduce the cost. Collecting a data from lot is cheap and economically advance.· It is quick and fast for collection of data for a researcher.
· If population of bricks is too large then this is only practical method carried out.
· It is much easy to get information from the individuals in a lot
· It will give detailed information to the researcher about the bricks or a complete stack or lot
· It also helps in the improvement of quality of bricks
DISADVANTAGES OF SAMPLING METHOD
- 1) It is difficult for careful selection of sampling
- 2) This work needs experts for careful study
- 3) If the information is required for each and every unit of bricks then it will be difficult to carry out the tests
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