 Myself, Mr. Yusuke Kulkarni, assistant professor at Balchand Institute of Technology, Sholapur, I am here to discuss with you on topic Concrete Mixed Design by IS Method. Learning outcomes of today's session. At the end of this session, students will be able to explain Concrete Mixed Design by IS Method. They will be able to perform Concrete Mixed Design in laboratory. Mixed Design can be defined as the process of selecting suitable ingredients of concrete, remember, and determining their relative proportions and what will be the object. Object will be of producing concrete of certain minimum strength and durability as economically as possible. Economy is also important, remember. So, determining the proportions of ingredients of concrete is mixed design. Now, one more thing is that for workable mixes, the strength of concrete varies as an inverse function of water cement ratio. This thing is important, one should know it. Now, since the quantity of water required depends upon the amount of paste, remember, it is important that this paste should be as little as possible and hence importance of grading is there. Here we can see concrete freely flowing. Now, there are certain variables in proportioning which are those water cement ratio is there, cement content is there, cement aggregate ratio is there, gradation of aggregates is equally important, consistency of the paste is equally important. Now, let us see step by step procedure of mixed design. There are different methods of mixed design, but today we will go by IS method. IS 10262 2009 gives detailed procedure of this particular method. So, which are the steps? First step is calculation of target strength of concrete, remember. This is the first step. Then, selection of water cement ratio. Next, selection of water content from it, selection of cement content for concrete, then estimation of aggregate proportion, estimation of the mixed ingredients and trial mixes. These are the important steps. We will see one after another these steps. So, this is the first step. So, calculation of target strength. Target strength FT is given by FCK plus 1.65S, where this S stands for standard deviation. For different grades of concrete, these are the standard deviation values which are to be used. Then, selection of water cement ratio is the next step. So, there are standard curves given by IS codes and IS 456 gives these curves. These curves are to be used for determining water cement ratio and these curves are, this is one curve for water cement ratio of concrete mixed design. Here, you can see water cement ratios and here you can see 28 days compression strength of concrete. So, you can choose water cement ratio from here. Here, this curve also is important depending upon grade of cement and water cement ratio and concrete strength. So, these two curves are to be used. Now, step three, selection of water content for concrete. So, concrete is to be designed with selection of water content by referring to this particular table. Say nominal maximum size of aggregate, if it is 10 mm, maximum water content should be 208 liters, remember. For 20 mm, it is 186 and for 40 mm, it is 165. So, these are the limitations given by code and these have to be followed in order to get good mix. Now, selection of cement content. Cement content depends upon exposure of concrete to environment. For mild exposure, minimum cement content is given as 300 kg per cubic meter, remember. And pre-water cement ratio is 0.55 for m20 grade of concrete. Likewise, these are the values given by ice code. These are to be referred. Then calculation of aggregate ratio. Aggregate ratio for zone 1, zone 2, zone 3 and zone 4 ratio are to be found using these tables. Then here, mass of fine aggregate is first calculated using the relations given in the codes. Then, coarse aggregate, then estimation of mixed gradient and then trial mixes. Remember, once you got the proportions, they cannot be used directly unless and until they are tested in the form of trial mixes. And once the results are satisfactory, they can be used on site. So, here we will see one sample mixed design for m25 grade of concrete, remember. So, here all the steps are given, step by step the procedure is followed and the results are obtained. You can go through this. Determination of target strength. Target strength comes to be 31.6 Newton per mm square. Then step to selection of water cement ratio. So, using IS-456 table 5, get for maximum mild exposure condition, the maximum water content is 0.55. So, adopt 0.5 likewise. So, selection of water content from that, maximum water content comes to 186 kg from table 2 of IS-10262. For nominal maximum size of aggregate, 20 mm. So, here for slump say from 50 to 75 mm slump, the correction in water content should be like this. These things are estimated water content by after applying the correction comes to be this much. Then selection of cement content is there. Minimum cement content given by IS is 300 kg per cubic meter. By calculations done here, we get 383.2, it is greater than 300, hence it is okay. Maximum cement content is 450, remember. Limitation on maximum cement content is 450 kg per cubic meter. Then estimation of aggregate proportions. For zone 2, this is a zone 2 sand, zone 2 aggregate. And the content water cement ratio is 0.5. Volume of coarse aggregate per unit volume comes to be 0.62. Then the workability considerations are there. Corrections are to be made in the aggregate proportions. And see here for every plus or minus 0.05 change in water cement ratio, the coarse aggregate proportion is to be changed by 0.01. So, these adjustments are given in the code are to be done. And then estimation of mix and get ingredients we get for 1 cubic meter of concrete. Cement so much so many cubic meters. Volume of water is also there. Volume of aggregates, mass of aggregates can be found from them. Because we know the density, we can find mass. Mass of fine aggregate is this much. And then trial mix proportion is obtained 1 is to 2.089 is to 2.837. Now, this proportion is to be checked by mixing a trial one or taking a trial mix. And then only they will be finalized. So, we will stop a while here. Here is one review question friends for you. Number one, in IS code method of concrete mix design, proportions of ingredients obtained are to be measured by weight, by volume or by both methods. So, get the correct answer right here. And IS number dash dash is used for concrete mix design, pick up the correct answer, write your answers. So, here are the answers. Question number one, A is the option, correct option A by weight. And question number two, B is the correct option, IS 10262 dash 2009. So, these are the answers. See, these are the references for today's session. Go through these references. Thank you.