1 M.Selvasundari, 2 Dr.G.Ramakrishna. 2 Department of Civil Engineering, Pondicherry Engineering College, Puducherry

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1 ISSN MECHANICAL STUDIES ON SELF COMPACTING SELF CURING CONCRETE USING LIGHT EXPANDED CLAY AGGREGATES 1 M.Selvasundari, 2 Dr.G.Ramakrishna 1 Department of Civil Engineering, Pondicherry Engineering College, Puducherry- 2 Department of Civil Engineering, Pondicherry Engineering College, Puducherry selvasundari9@gmail.com, 2 grkv1@pec.edu Abstract Self-compacting concrete (SCC) is a special type of concrete that has excellent deformability and high resistance to segregation and can be filled in heavily reinforced or restricted area without vibration under its self-weight. Self-curing concrete is the one which can cure itself by retaining its moisture content and has a significant effect on the hydration and moisture movement. Light expanded clay aggregates (LECA) is used as the self-curing agent in self-compactinconcrete and enhances the properties of self-compacting concrete. In the present study, self-compacting concrete. The addition of LECA reduces the weight of concrete with self-curing is made by partially replacing LECA as coarse aggregate. The coarse aggregate was replaced by the various proportions of LECA from % to 2% at % interval by volume of coarse aggregate. Mechanical properties such as compressive strength, Split tensile strength and flexural strength of self-compacting self-curing concrete with different proportions of LECA were studied. As a result the 1% replacement of LECA gave higher mechanical properties compared to other proportions and conventional concrete. Keywords: - Self compacting concrete, self curing, LECA, compressive strength, split tensile strength, flexural strength SCC, the mineral admixture such as fly ash, silica I. INTRODUCTION fume, GGBS and super plasticizer should be A Self-compacting concrete (SCC) is a special type of concrete that has excellent deformability and high resistance to segregation and can be filled in heavily reinforced or restricted area without vibration under its self- weight [2]. SCC consists basically of the same constituents as a normally vibrated concrete. However, there is a clear difference in the concrete composition. To enhance the flow of used. SCC properties are greatly influenced by admixture type, its dosage and filler [3]. Selfhighly engineered compacting concrete is concrete with much higher fluidity without segregation and is capable of filling every corner of form work under its self-weight []. Self- own weight for compacting concretes, use their flowing, and do not have sufficient internal

2 ISSN energy of motion when lightweight aggregate is used, and compared with the concretes with natural aggregate. They are slightly slower and the worse flow through dense wrap of reinforcement [4]. In the making of concrete, aggregates particularly the coarse aggregates play an important role. They give bulkiness as well as provide strength to concrete. Since they form the major amount, the properties of concrete depend on the characteristics of aggregates. In order to reduce the self-weight of concrete, attempts have been made to use light weight aggregates since long back. Light weight concrete is being used before the Christian era using the natural volcanic aggregates of pumice and scoria. Because of low density and thermal insulating properties, light weight aggregates has become an important construction material in recent days and this has led to the development of synthetic light weight aggregates made from raw material like clay, shale etc. and industrial by-products like fly ash, slag ashes etc. To attain desirable strength and other properties, curing is necessary. Curing is the process of controlling the rate and degree of moisture loss from concrete during hydration of cement. The need for adequate curing of concrete cannot be overemphasized because curing has a strong influence on the properties of hardened concrete. Proper curing will increasee strength, durability, water tightness, abrasion resistance, volume stability, and resistance to freezing and thawing effect. Generally, curing is being done using conventional methods such as ponding, fogging, sprinkling, and covering with saturated materials etc [6]. The concept of self-curing is to reduce the water evaporation from concrete and hence increase the water retention capacity of the concrete compared to ordinary concrete. Scarcity of potable water increases day by day. The use of self-curing agent is very important from the point view that water resources are getting valuable every day. Hence, an attempt has been made in the present work to study the suitability of Light Expanded Clay Aggregates (LECA) as a self- the strength of curing agent and also to evaluate Self Compacting Self Curing Concrete (SCSCC).. II. MATERIALS A. CEMENTITIOUS MATERIALS: Ordinary Portland cement Of 43 grade conforming to IS: is used. The specific gravity of cement is found to be 3.1. The class C fly ash obtained from Neyveli Lignite Corporation is used as a mineral admixture. The specific gravity of fly ash is 2.7. B. FINE AGGREGATE AND COARSE AGGREGATE Locally available river sand is used as natural fine aggregate. River sand conforms to aggregate grading zone II. Naturally crushed coarse aggregate of size 2mmm and 12mm is used in this study. It is tested as per IS: The properties of fine & coarse aggregate are presented in Table 1. C. LECA Light expanded clay aggregates (LECA) is made from clay which is capable of expanding and the base material is plastic clay. LECA are produced in a rotary kiln by wet process using bloating clay. The clay dries and expands in rotary kiln at high temperatures of about 11-12ºC. The cellular structure formed is used as light weight aggregate whichh is called as light 32

3 ISSN expanded clay aggregates. It gives lower density to concrete. The properties of LECA are presented in Table1. S.N O Fig. 1 LECA TABLE-1 PROPERTIES of AGGREGATES Properties Fine Coarse LECA aggrega aggrega te te 1 Specific gravity 2 Bulk density(kg/ m 3 ) 3 Finess modulus 4 Water absorption D. CHEMICAL ADMIXTURES Super plasticizer used for SCC is to achieve its properties is Superflo special. The optimum dosage for super plasticizer to attain good workability in SCC is found to be 2.% conforming to IS The SCSCC mix design was prepared as per guidelines prescribed by EFNARC specifications. The SCC mixes were made by partially replacing coarse aggregate as LECA. The aggregates were pre-wetted for 24 hours and used in the saturated surface dried condition [SSD] while making the mixes. The replacement of coarse aggregate was made from % to 2 % by volume, at % intervals. Mix is marked with letters CM for control mix and L for LECA replacement and the subscripts denotes for replacement levels. Mix proportions of all mixes are shown in Table- 2. TABLE-2 MIX PROPORTIONING C L L 1 L 1 L 2 L 2 M Cement 3 Flyash 1 Fine aggregat 9 e Coarse aggregat e Leca Plasticiz er (l/m 3 ) Water III. METHODOLOGY B. Properties of SCSCC A. Mix Proportioning 1) Fresh properties: The fresh properties of SCC i.e. filling ability and passing ability has 33

4 ISSN been carried out based on the EFNARC specifications for different mixes in order to determine self compactability properties. Slump flow test was conducted to measure the filling ability and J-ring test was conducted so as to ensure the passing ability of self-compacting concrete. 2) Hardened properties: The hardened properties of SCC such as compressive strength using 1 mm cubes,split tensile strength with 1 mm x 2 mm cylinder and flexural strength with mm x 1 mm x 1 mm prisms were carried out as per IS: 16:199 and ested at the age of 7 and 28 days. Fig. 3 J-ring TABLE-3 FRESH PROPERTIES OF SCSCC IV. RESULTS AND DISCUSSION A. Fresh properties of SCSCC The fresh properties of self-compacting self- of curing concrete made with partial replacement LECA as coarse aggregate is shown in table 3. It is observed that the results of SCSCC are conforming to EFNARC specifications. Slump flow (mm) Recomm ended values C M L 68 L 1 68 L 1 69 L 2 62 L 2 61 J- ring (mm) < B. HARDENED PROPERTIES OF SCSCC Fig. 2 Slump flow The hardened properties such as compressive strength, split tensile strength and flexural strength were obtained at 7 and 28 days as per IS: 16:199. 1) COMPRESSIVE STRENGTH: The compressive strength of SCSCC is listed in table- 4. From the test results it is observed that the addition of LECA has gradually increased the compressive strength upto 1% replacement and 34

5 ISSN then decreases. The compressive strength of SCSCC with inclusion of LECA gave higher strength more than control mix. 1% replacement of LECA gave higher compressive strength at 7 and 28 days than other replacement levels. Fig. Graphical representation of compressive strength 2) Split tensile strength: The split tensile strength of SCSCC is listed in table-. From the test results it is observed that the addition of LECA has gradually increased the split tensile strength upto 1% replacement and then it decreases. The split tensile strength of SCSCC with inclusion of LECA gave higher strength more than control mix. 1% replacement of LECA gave higher split tensile strength at 7 and 28 days than other replacement levels. Fig. 4 Compressive strength TABLE-4 COMPRESSIVE STRENGTH OF SCSCC Mix id Compressive strength (MPa) 7 days 28 days Fig. 6 Split tensilee strength CM L L TABLE- SPLIT TENSILE STRENGTH OF SCSCC L Mix id Split tensile strength (MPa) L L days CM days

6 ISSN L L L FLEXURAL STRENGTH OF SCSCC Mix id Flexural strength (MPa) 28 days L L Fig. 7 Graphical representation of split tensile strength CM L L 1 L ) Flexural strength: The flexural strength of SCSCC is listed in table-. From the test results it is observed that the addition of LECA has gradually increased the flexural strength upto 1% replacement and then it decreases. The split tensile strength of SCSCC with inclusion of LECA gave higher strength more than control mix. 1% replacement of LECA gave higher flexural strength at 7 and 28 days than other replacement levels. Fig. 8 Flexural strength TABLE-6 L 2 L V. CONCLUSION From the test results with inclusion of LECA as self curing in SCC the conclusions made are as follows; i) The SCSCC mixes with inclusion of LECA satisfies the fresh properties as per EFNARC specifications. ii) The compressive strength of SCSCC with inclusion of LECA gave higher strength when compared to control mix at 7 and 28 days. The 1% replacement of LECA as coarse aggregate under self-curing gave higher compressive strength of 38% when compared to control mix. iii) The split tensile strength of SCSCC with inclusion of LECA gave higher strength at 1% replacement with an increase of79 % compared to control mix. 36

7 ISSN iv) Flexural strength of SCSCC has achieved higher strength at 1% replacement of LECA when compared to control mix. v) Compressive, split tensile and flexural strength has gradually increased upto 1% replacement and then it decreases as the replacement percentage decreases. ACKNOWLEDGEMENT I would like to express my deepest sense of respect and indebtedness to Dr. G. Ramakrishna, Professor, for his consistent support, guidance, encouragement and advice. REFERENCES 1. Abinaya A., J. Jaccilin Santhya, A. Jerina, P. Srinidhi, J.T. Walter,D. Brandon, Experimental investigation on self compacting concrete using light weight aggregate, International Journal of ChemTech Research, 1(8), 217, pp Gopi Rajamanickam and Revathi Vaiyapuri, Self Compacting self curing concrete withl ight weight aggregates, Gradevinar, Vol. 68, No. 4, 214, pp Gopi, V.Revathi, R.Ramya, K.Ramesh, Saturated Light Expanded Clay Aggregate and Fly Ash Aggregate as Internal Curing agents in Self Compacting Concrete, Australian Journal of Basic and Applied Sciences, 9 (31), 21, pp Maghsoudi AA, Mohamadpour Sh, Maghsoudi M., Mix design and the mechanical properties of self-compacting light weight concrete, International Journal of Civil Engineering, vol. 9, 211, pp Okamura H. O., (1999), Self Compacting Concrete Development, Present Use and Future, 1st International RILEM Symposium on Self - Compacting Concrete, RILEM Publications SARL, pp Shankar M., Experimental Investigation on Self Compacting Concrete Using Light Weight Aggregates, International Journal of Advanced Science and Engineering Research, Vol. 1, Issue 1, 216, pp