Address for Correspondence

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1 International Journal of Advanced Engineering Technology E-ISSN Research Paper SOME STUDIES OF VARIOUS MODIFIED MORTAR AND GROUTING MATERIAL (AS A REPAIR MATERIAL) TO REPAIR UNCONTROLLED (HONEYCOMBED) CONCRETE Kamlesh S.Dalal 1, C.D.Modhera2, S.A.Vasanwala 3 Address for Correspondence 1 Research Scholar, 2 Professor, 3 Professor Applied Mechanics Department S V National Institute of Technology, Surat , Gujarat, INDIA ABSTRACT Strength of concrete is commonly considered its most valuable property, although in many practical cases other characteristics, such as durability and permeability, may in fact be more important, Nevertheless, Strength usually gives an overall picture of the quality of concrete. Water cement ratio and compaction effects vital role for strength of concrete, In this experimental study seems the compressive strength of uncontrolled concrete is decrease about 56% to 59% with respect to controlled design mix concrete. We observed compressive strength of repaired specimen (of uncontrolled concrete) by epoxy, acrylic base and rubber base injection grouting and surface repair, it increase 76%, 25% and 20% compressive strength than honeycombed specimen respectively. We also study and find flexural strength of repaired specimen by epoxy, acrylic base and rubber base injection grouting, it increase 20%, 15% and 12% flexural strength than honeycombed specimen respectively. It was also noted that compressive strength of various repair materials like Microconcrete is 117% higher than design mix (Controlled) concrete and compressive strength value of rubber base PMM is 20% higher with respect to concrete and compressive strength of acrylic base PMM is 25% higher than concrete. KEY WORDS: Compressive strength of controlled concrete and various repair material, flexural and compressive strength of honeycombed and repaired specimen by various grouting material 1. INTRODUCTION To realistically appraise the position of concrete repair technology and the complex fabric of problems it faces today, we must pause periodically to review where we are and where we might be going. The majority of faults and problems are caused by lack of attention to design details, specifications and poor insitu workmanship. Material, although important, is less of an evil. Material, per se, does not perform; the end product made from a material the repaired structure performs. The concern should not be solely with repair materials themselves, but with the uses to which they are being put, with the gray area of overlap between material properties and the end engineering product the repaired structure. In our study we present different treatments, and problems leading to unsatisfactory performance of repaired concrete structures. With the beginning of the third millennium, one must recognise that a very large number of existing concrete structures worldwide are in a state of deterioration/distress. At the same time, it must also be recognised that many repaired concrete structures are severely deteriorated only after a few years having been repaired. Each country is facing this major challenge: How to repair, rehabilitate and protect the current stock of concrete structures in order to prolong their service life. All over the world, concrete has been well and truly used all the way throughout the centuries. In recent years the image of concrete has been shaken by durability problems, by often poor performance, and most of all, by concrete repair failures. The repair failures and endless repair of repairs made a considerable contribution to the current perceptions of concrete. The poor durability performance of many concrete structures is causing disruption and expenditure on remedial works which owners and society cannot afford and do not wish to see repeated. In recent years the image of concrete has been shaken by durability problems, by often poor performance, and most of all, by concrete repair failures. That perhaps, is the main challenge in concrete technology for the 21st century. 2. CONCRETE REPAIR AND MATERIALS Deterioration and distress of repaired concrete structures in service are a result of a variety of physico-chemical processes such as the corrosion of embedded reinforcing steel, freezing and thawing, etc. The most serious deterioration processes leading to repair failures are caused by the cracking of the repair material, In concrete and other cement-based materials, micro- cracks already exist at the aggregate-mortar and reinforcement-mortar interfaces. When large, visible cracks become interconnected with micro-cracks, the network of cracks facilitates the transport of aggressive ions and gases to the embedded reinforcement, leading to premature corrosion and deterioration. Much has been done during the last decade and even more is underway in addressing the important issues related to the compatibility of repair materials and their ability to resist cracking. The structure of cementbased materials is complex. It is a heterogeneous mixture of diverse components with widely varying characteristics and properties. It is a physicochemical component consisting of hydrated cementitious materials, aggregates, additives and admixtures. With composite systems, such as repair, the complex link between phenomena, theory and descriptive parameters encourages a more detailed study of the materials based on the properties of the component phases and how these interact. Unquestionable progress has been made in the field of repair materials. But the material that has the required properties for a particular application is only one stage in the complex system that makes up the totality of concrete repair. The problem of durable concrete repair is more complex than it appears at first sight, we can say Materials are indifferent; but the use we make of them is not a matter of indifference. So, if material does not perform, how can we call it high-performance material??

2 International Journal of Advanced Engineering Technology E-ISSN Furthermore, before we continue to discuss the subject of repair materials intelligently, we have to ask ourselves The problem of durable concrete a question, What do we really mean by a highperformance material - high performance for what? The answer to this is anything but obvious. In our case, experience clearly demonstrates that conditions that impair the ability of any concrete or repair material in one structure to serve its desired purpose would not necessarily impair that in another structure to the same degree. 3. EXPERIMENTAL PROGRAM For smoothly conduction the experimental work, the whole work was divided into following phases: Phase I : Providing the ingredient and necessary materials : Testing of Ingredient, Carry out Mix Design for proportion and Uncontrolled concrete. Phase : Experimental Program- Casting & Testing II 1. Comparison of compressive strength of controlled and uncontrolled concrete. 2. Comparison of Compressive Strength of Various Repair Materials 3. Check Compressive Strength of Honey combed Specimen and after Repair with Various Repair Material. 4. Check Flexural Strength of Honey combed Specimen and after Repair with Various Repair Material. Phase I A. Concrete The following ingredients materials were procured for concrete. Cement: (OPC) 53 grade were used Properties of Cement S. Test Results No. 1. Fineness (By Blaine s 3369cm 2 /gm Method) 2. Setting Time Initial Final 3. Compressive Strength (kg/cm 2 ) 3 days 7 days 28 days 4. Soundness (Le Chatterley s Method) Expansion between two joints 90 Minutes 230 Minutes mm 5. Normal Consistency 29.5% Aggregate: Sand was procured from Tapi River IS: Sieve designation Sieve Analyses of Aggregates Natural Coarse aggregate 20 mm down size 10 mm down size Cum Cum Cum % of % of % of retained Passing retained Cum % of Passing Cum % of retained Fine Aggregate (Sand ) Cum % of Passing 40 mm mm mm mm mm mm mm Micron Micron Micron Physical Properties of Coarse Aggregate & Fine Aggregate Properties Coarse Aggregate 20 mm 10 mm Fine Aggregate Fineness Modulus Specific Gravity Bulk Density (kg/m 3 ) Water: The potable water was used during experiment program Recommended concrete mix proportion: Based on the properties of the ingredients supplied the proportion by weight was worked out using I.S. method of Mix Design IS: , Recommended procedure for Designing concrete mixes for general types of construction. Trial mixes were prepared based on the proportion obtained from calculation and based on the compressive strength and the slump observed for trial mixed the following proportion is recommended. The testing of the concrete was carried out as per relevant Indian Standards. Recommended concrete mix Proportion (By Weight) Cement : Sand : Coarse Aggregate 1 : 2.5 : 3.8 W/C = 0.52(Designed), 0.73*(Actual) *The proportion has been compacted manually Properties of fresh mix Description Slump (mm) Compacting Factor (C.F.) Controlled concrete Uncontrolled concrete

3 International Journal of Advanced Engineering Technology E-ISSN B. Repair Materials 1. SBR (styrene butadiene rubber) 2. Acrylic polymer modifier for cementitious composite 3. Microconcrete 4. Epoxy (for injection grouting) Comparison of compressive strength controlled concrete & uncontrolled concrete Concrete Cube 150x150x150mm Compressive Strength At 7 days (kg/cm2) Compressive Strength at 28 days (kg/cm2) Cube 150x150x150mm Compressive Strength at 24 hours (kg/cm 2 ) Air Curing Compressive Strength at 7 days (kg/cm 2 ) % Effect Compressive Strength 7 days Compressive Strength at 28 days (kg/cm 2 ) % Effect Compressive Strength 28 days Controlled Concrete Uncontrolled Concrete Compressive Strength % decreases Comparison of compressive strength of various repair materials Concrete Design PMM with SBR PMM with APM Mix (Rubber base) (Acrylic Base) Micro Concrete 1 : 2.5: % 121% 118% 216% % 125% 120% 217%

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5 Cylinder (150mmdia x 300mm) % Increase Strength International Journal of Advanced Engineering Technology E-ISSN Comparison of Compressive Strength of repair cylinder with various repair material Fck (Kg/cm²) Com.Strength(Kg/cm²) After Com.Strength (Kg/cm²) Com.Strength (Kg/cm²) Honeycombed Repair with Epoxy Injection After Repair with Acrylic After Repair with Rubber specimen Grouting & surface repair Injection Grouting & base Injection Grouting & surface repair surface repair % % % % % Increase Strength Increase Compressive strength with various repair material Comparison of Flexural Strength of Beam Repair with various grouting material Fb(Kg) Honey combed specimen Fb(Kg) After Repair with Epoxy Injection Grouting Fb(Kg) After Repair with Acrylic Injection Grouting Fb(Kg) After Repair with Rubber base Injection Grouting Increase Flexural strength with various repair material

6 International Journal of Advanced Engineering Technology E-ISSN RESULTS & DISCUSSION Effect on compressive strength of controlled concrete and uncontrolled concrete is significant. It can be seen that the compressive strength of uncontrolled concrete decrease about 56-59% with respect to controlled concrete. Comparison of compressive strength of various Repair materials (fck).\compressive strength of Microconcrete is 117% higher than design mix concrete and compressive strength value of rubber base PMM is 25% higher with respect to concrete and Compressive strength of acrylic base PMM is 20% higher than concrete for 28 days results. We also find that Microconcrete achieved 210 kg/cm² within 24 hours. It is also observed, compressive strength of repaired specimen by Epoxy, Acrylic base and Rubber base injection grouting, it increase 76%, 25% and 20% compressive strength than honeycombed specimen respectively. We also study and seen as results, we find flexural strength of repaired specimen by epoxy acrylic base and rubber base injection grouting, it increase 20%, 15% and 12% flexural strength than honeycombed specimen respectively. 5. CONCLUSIONS From this experimental study we observed certain points., if water cement ratio is increase 21% and concrete is not compacted well, strength is significantly decrease more than 55%, Buildings erected by such quality of concrete are most vulnerable for durability aspect, and need early repair due to premature deterioration. During repair of honeycombed specimen by various injection grouting material and surface repair, Epoxy resin recover the good strength in compare to polymer and Acrylic base injection grouting and surface repair. Basically concrete repair is compromise up to such extent, it will more effective by use of compatible repair material with parent concrete. 6. SCOPE OF FUTURE STUDY In spite of so many studies nowadays, so many dark areas in concrete repair which need further studies, but the priorities must be given to the following Study compatibility of repair material with respect to concrete substrate. Points are as under Thermal expansion contraction complex issue of electro-chemical incompatibility Chemical reactivity. Corrosion of steel embedded in cementbased materials. Behavior of repair material in stressed and distressed condition. Curing shrinkage of repair material relative to the concrete substrate Modulus of elasticity in compression Permeability aspect Behaviour of material in saline environment Freeze & thaw effect REFERENCES: 1. EMMONS, P.H., and VAYSBURD, A.M. The total systems concept for improving performance of repaired structures. Concrete international, No.3, March 1995, pp MAYS, G. and WILKINSON. W., Polymer repairs to concrete: Their influence on structural performance. ACI-SP , Katherine and Bryant Mather International Conference. 3. PLUM D.R. The behaviour of polymer materials in concrete repairs and factors influencing selection. The Structural Engineer. September 1990, pp EMSERSON, N.K. and MAYS, G.G., Significance of property mismatch in the patch repair of structural concrete Part 1: Properties of repair systems. Magazine of Concrete Research, September 1990, 42, No. 152, pp MEHTA, P.K. Concrete technology at the crossroads Problems and opportunities. ACT -SP-1 44, 1994, pp HALL. C. Mechanical and thermal properties. Polymer Materials, Second edition, Macmillan 1989, pp SPRINKAL. M. Thermal compatibility of their polymer- concrete overlays. Transportation Research Record, 1983, IV, 76. pp MAILVAGANAM.N.P., Repair and protection of concrete structures. CRC Press 1992, pp EMMONS, P.H. and VAYSBURD, AM. Compatibility considerations for durable concrete repairs Research Board Annual Meeting, Washington DC, January 1993, pp ANON, Four step to successful concrete repair. Concrete Construction, January 1983, pp HINDO, KR. In place bond testing and surface preparation of concrete. Concrete International, No. 9, September 1989, pp STENLY,C.C. The History of Concrete. Cement and Concrete Association (C&CA), U.K., EPICTETUS, Discourses, Book 2, Chapter PATERSON, The structural engineer in content, Structural Engineer, 1984, Vol. 62A, No 11, pp URRETA, J.L Pathology investigation of the whole road bridges of a region; Methodology and correlations,. Proceedings of the Conference on Structural Faults and Repair 93, Vol 1, pp HAUSER, R. Lessons from European failures. Concrete International, 1979, No 12, pp FRACZEK, J. ACI survey of concrete structure errors, Concrete International, 1979, No. 12, pp