Experimental Understanding on the Relation of Compressive Strength with the Addition of Super Absorbent Polymer

ABSTRACT

Wasting water is never been encourage by anyone in today scenario because we all knew that the water scarcity is been on many places and we need to take steps to reduce the wastage of the water. When it comes to construction field curing is more necessary for gaining strength at the same time and lack of proper curing can badly affect the strength and endurance properties of the concrete. A proper curing with sufficient amount water is necessary to be provided to the concrete structures at its initial stages in order to gain the full strength. We have also witnessed the places with water scarcity and for a fact that curing requires more amount of water makes the construction in such places tougher. While curing process a large amount of water is also wasted by improper maintenance and application of water. The self-curing concrete is the concrete, which has the ability to cure itself by preserving the water with in it. The present research work focuses on self-curing of concrete, it work includes the addition of the super absorbent polymer in the concrete in the percentages of 0%, 0.5%, 1%, 1.5%, 2% by the weight of the cement for different mixes such as M20, M30, M40.

Keywords: concrete, self-curing, strength, cement, wasting water.

1 Introduction

Concrete is one of the promising and advance technology which has been increasing day by day. The concrete is known for its properties which make the it last long and its service which it provides to the world where numerous constructions and the structures are being constructed and are being used. The concrete is everywhere in today world in the form of transport system or in the form of the shelter or in the form of the water saving projects , everywhere the concrete is in need such is the importance of the concrete and its structures whiles as we have seen the immense need of concrete but there is also need to make the concrete structure in such a way that it can fully provide its service for which it is acknowledged such as strength and the durability. The main factor which affects the strength and durability of the concrete is curing which is done once the casting of the structure is done. The curing plays a important role in gaining the strength that is why the concrete structures are cured in the water for about 28days to gain the strength for which it is known for. The curing needs the water and today we are facing the scarcity of the water and there is been lot of measures that are being taken to reduce the wastage of the water and to overcome the draught season in many places and what about the place where there is more scarcity of the water how are we going to cure the structures this research is all about using the different curing methods and different methods where we can reduce the wastage of the water here comes the term internal curing which is done by some materials which cure the concrete internally and help the concrete to attain the strength which is needed for it. These materials are called the Self curing agents. The best known agents are like super absorbent polymer(SAP) these agents not only increases the strength of the concrete but also it shows significent affect on the other properties in the concrete such as the utilization of SAP in the concrete has shown to be reducing the penetrating of the chloride in to the concrete and also there is redcution of the shrinkage which ultamately results in reducing the cracks in the cocnrete.

Shohana Iffat et al; Studied on SAP to see how it affects the properties of concrete. This study is done in Bangladesh. The SAP is added in concrete and it was found that the SAP samples were found to desorbed more than 90% of the absorbed water. The samples with SAP has shown 18% rise in strength compare to the normal concrete samples. The chloride penetration is 15% less compare to the normal concrete.

M.S Sai Kumar et.al ; directed a study on the use of SAP in the concrete. The SAP percentages used in the study is 0%, 0.1%, 0.2%, and 0.3% 0.4%, 0.5%. The water-cement ratio taken in the study is 0.4. From the study it is concluded that the 0.3% of SAP is perfect to get the good results and the results have increases anonymously of about 34%. juntao Dang et. al; Studies on the change in behavior of properties of concrete when SAP is added. Addition of Fly Ash in the concrete to the weight of the cement up to 45% and at size of C.A of 20mmm the SAP is used at different percentages. The result shows that the 0.3% of SAP has generated the best results. The compressive strength is increase and part from the compressive strength the other properties of the concrete such has shrinkage has reduced, carbonization resistances has increased when compared to the convectional concrete and the chloride penetration has reduce compare to the normal concrete.

Karthikeyan et.al; Studied on the how concrete is cured when SAP is used and what are affects it shows in the concrete. In the study it was perceived that the fly ash is cast-off in the concrete and the mix is M30 the results concluded that the SAP of about 0.3% has generated the best strength to the concrete. It is also stated that the SAP concrete samples are more economical when compare to the normal concrete

2 Materials and Methods:

Normal materials which are used in the concrete is used and along with it super absorbent polymer is used in the process. the materials such as cement, sand, coarse aggregates and the super absorbent polymer are brought from the near by retail shops. The materials are not directly used in the concrete they are first tested for the priliminary tests to check the quality of the materials and then they are considered tp be used in the concrete.

2.1 CEMENT

The cement used in the research work is OPC 53 grade which is been tested for its properties and found to be adequate to be used in the research work and the company is Bharathi Cement.

Table 1: Showing test results on Cement

Abbildung in dieser Leseprobe nicht enthalten

2.1.2 FINE AGGREGATE

The natural river sand of size below 4.75mm is used.

Table 2: Showing test results on F.A:

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2.1.3 COARSE AGGREGATES (C.A):

The C.A used in the research work is crushed angular aggregates and the size of the C.A is 20mm.

Table 3: Showing test results on C.A:

Abbildung in dieser Leseprobe nicht enthalten

2.1.4 SUPER ABSORBENT POLYMER (SAP):

The SAP is one of the trending name which we been hearing now a days in the field of construction. The ability to cure with less water surely gives many advanatages and it is provding its service at its best the laboratory and the field results has shown clealry the profit of using the SAP in the cocnrete. If we put it in simple the SAP is acryl acid copolymers. The SAP is available in both powder and solution form. When we add SAP in the concrete and the SAP particles absorb the water and increases its particle size 3 times larger than before. It is seen that the 50% swelling id obatined at its 1st minute.

2.1.5 PHYSICAL PROPERTIES OF SAP:

Table 4:

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2.1.6 CHEMICAL PROPERTIES OF SAP:

Table 5:

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2.2 MIX PROPORTIONS :

2.2.1 MIX PROPORTION OF SAP WITH M20 MIX:

Table 6:

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2.2.2 MIX PROPORTION OF SAP WITH M30 MIX:

Table 7:

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2.2.3 MIX PROPORTION OF SAP WITH M40 MIX:

Table 7:

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2.3 Procedure obtained in Present Research Work:

Experimental investigation is done in the present research work. The materials are collected and the priliminary tests on the materials are done to check the quality of the materials. The data obtained from the tests are used in making the mix design of the concrete for different mixes such as M20, M30, M40. The data on super absorbent polymer is obtained from the past research works about is it edible to use it in ht e ocncrete or not by considering the past research works the super absorbent polymer is considered to involve in the present rewsearch work as a curing agent. Once the mix design is obtained the concrete samples are casted and the super absorbent polmer is added to the weigth of the cement at percenatges of 0%, 0.5%, 1%, 1.5%, 2% to the concrete mix. Both the samples of convectional concrete and the concrete with super absrbent polymer are casted to know the difference of the achievable strength. The convectional concrete samples are cured in the normal water and the concrete samlples with super absorbent polymer are cured without water. The tests are conducted on the concrete specimens and the results are evaluated.

3.Tests and Results:

The primilinary tests and mechnaical tests are done on the concrete. The priliminary tests results are shown in above and the mechnanical tests which are done is compresssive strength test is done on specimens of different mix grades.

3.1 Tests on the Fresh Concrete:

The slump cone test is done on the fresh concrete to know about the workability of the fresh concrete. The standard slump cone test procedure is been followed to check the workability of the fresh concrete.

3.1.1 SLUMP CONE TEST

"Slump test is used to determine the workability of fresh concrete".

Table 8:

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3.1.1.2 GRAPHICAL REPRESENTATION OF SLUMP TEST FOR DIFFERENT PERCENTAGES OF SAP:

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3.2 Mechanical Tests on the Concrete:

Among the different mechanical tests the present research work is focued to know more about the compressive strength. The specimens are casted and cured for 7,14,28,56 days after the respective days the specimens are tested on the compressive testing machine and the results are evaluated. The compressive stresngth testing machine showed the values in Mpa

3.2.1 COMPRESSIVE STRENGTH OF CONCRETE FOR M20 MIX WITH SAP:

The M20 specimens are casted for 7,14,28,56 days the specimens are tested on the automatic compressive testing machine and the values are recorded. The below table shows the compressive strength values.

Table 9:

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3.2.1.2 GRAPHICAL REPRESENTATION OF COMPRESSIVE STRENGTH OF CONCRETE FOR M20 MIX WITH SAP:

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From the above figures it is evidently perceived that the compressive strength of the concrete increase with the addition of the SAP. The maximum strength of 30.33 MPa for 28days and 42.88 MPa for 56 days is obtained at addition of 1.5% of the SAP in the concrete.

3.2.2 COMPRESSIVE STRENGTH OF CONCRETE FOR M30 MIX WITH SAP:

The M30 specimens, which are casted for 7,14,28,56 days the specimens, are tested on the automatic compressive testing machine and the values are recorded. The below table shows the compressive strength values.

Table 10:

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3.2.2.1 GRAPHICAL REPRESENTATION OF COMPRESSIVE STRENGTH OF CONCRETE FOR M30 MIX WITH SAP:

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From the above figures it is clearly seen that the compressive strength of the concrete increase with the addition of the SAP. The maximum strength of 42.21 MPa for 28days and 49.7 MPa for 56 days is obtained at addition of 1.5% of the SAP in the concrete.

3.2.3 COMPRESSIVE STRENGTH OF CONCRETE FOR M40 MIX WITH SAP:

The M20 specimens are casted for 7,14,28,56 days the specimens are tested on the automatic compressive testing machine and the values are recorded. The below table shows the compressive strength values.

Table 11:

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3.2.3.1 GRAPHICAL REPRESENTATION OF COMPRESSIVE STRENGTH OF CONCRETE FOR M40 MIX WITH SAP:

Abbildung in dieser Leseprobe nicht enthalten

From the above figures it is evidently understood that the compressive strength of the concrete increase by the addition of the SAP. The maximum strength of 51.22 MPa for 28days and 60.99 MPa for 56 days is obtained at addition of 1.5% of the SAP in the concrete.

4. CONCLUSION

The research work is found to be successful and the results are good as the performance of the materials used in the research is good. There is particular amount or the percentage in which the SAP is needed to be added and addition of the SAP at the particular amount will give us good results in terms of strength where as the addition of the material more than the amount required will not give good results. As we have used different mixes in the research work like M20,M30,M40 we have also used different percenatages of super absorbent polymer such as 0%, 0.5%, 1%, 1.5%, 2% and the research has shown that addition of 1.5% of super absorbent polymer has given the highest amount of compressive strength and the addition of this polymer beyond the 1.5% has shown the reduction in the scompressive strength of the concrete. The super absorbent polymer used in the concrete has not only shown good results in the strength wise but also shown good results in the workbaility tests through which we caan conclude that the super absorbent polymer increases the workability of the fresh concrete. The results has clearly shown that the concrete with super absorbent polymer has shown better results and we can say that we can use SAP as a curing agent when there is scarcity of water but the percenatge should be maintained addition of this polymer in more amounts will not increase the strength it can only decrease the strength. The research study has shown us that the curing agents such as SAP are helpful in places where water is lesss, places where water is difficult to carry out and where the portable water is not enough available to be used for the curing process. the research study has also shown us that there is no need of external curing when we use the super absorbent polymer in the concrete as the sutdy has been conducted with a sole purpose to know will the SAP can reduce the external curing or not and can help us to build a world where, we can save water where there is need to save the water and the SAP has stand up to the expectations by showing the good results.

4.1 FUTURE SCOPE OF INTERNALLY CONCRETE BY SAP:

It is new way to see the world of concrete for large constructions there is need of large amounts if water to cure the structure and which results in the wastage of the water but through this technique we can redce the wastge of the water which is been done in the curing process. Still there is need for much more research work to be done on the usage of SAP in the concrete. Affect of the weather conditions are needed to be studied further more. Durability properties are needed to be studied more. There is need to further study about how the concrete which contains SAP will react to the acid attack which is very important to know for longer sustainance of the concrete structures.

3 Declarations

Study Limitations:

The preseant study uis only limited to the compressive strength of the concrete the flexural strength and the tensile strength are not considered in the study as the compressive stregnth is the strength which plays the vital role in the concrete structures. Durability tests such as acid attack are not included in the study since this study focueses on the strength of the concrete and is limited to 56 days.

Acknowledgements

I would whole heartedly like to thank my Allah almighty, my parents Shaik.Abdul.Razack and Sahik.Sayidaw Banu and my sister Shaik.Balkhis Banu and Shaik. Rehhana Banu who has supported me financially and morally to do this research work and I would like to thank to the lab asssiatants who have helped me in this research work with which, I was able to do the physical work easily.

Funding source

Provide funding source, supporting grants with grant number. The name of funding agencies should be written in full, if no funding source exist, write, none.

Competing Interests

There is no conflict in the research work as this research work is solely carried out by myself inorder to learn more about my research field.

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