A STUDY ON STRENGTH AND STRESS STRAIN BEHAVIOUR OF SELF CURING CONCRETE - ASSIGNMENT SOLUTION

INTRODUCTION

1.1 GENERAL

It is important to ensure adequate treatment of concrete structures that meet the desired performance and stability requirements. In conventional construction, it is achieved through an external treatment, applied after mixing, maintenance and finishing. Internal treatment is a very promising technology that can provide additional moisture in concrete for more effective hydration of cement and self-destructed. Internal treatment means starting a particular treatment agent that will provide additional moisture. At present, there are two main methods available for the internal treatment of concrete. The first method uses saturated light aggregate porous for the supply of internal water source (Eldblue) each, which is consumed by the chemical contraction during the hydration of the cement can replace the water. The second method uses superabsorbent polymers (SAP), because these particles are concrete can absorb water in large quantities during mixing and can make the free water containing large signals, likewiseduring the hydration of cement Prevent the extinction. For optimum performance, the internal curing agent must have a high water absorption capacity and a high rate of water absorption.

Self-treatment mixture that occurs when the availability refers to the hydration of additional internal water cement is not part of the water. "Traditionally, the means of treatment of concrete that is not lost from the surface of the water such circumstances, the treatment is considered to be" inside out. On the contrary, internal internal curing deposits' (fine light saturated consolidation, superabsorbent polymers or saturated wood fibers), the 'internal cure' is often referred to as self healing.

1.2Need for Self curing.

 When mineral additives react completely to the mixedcement system, their demand for water (external or
internal) can be significantly higher than traditional portland cement concrete. When this water is not available, it can cause capillary porosity, cracking due to its water pile (in early age).
 Internal treatment refers to the process by which cement hydration is due to the availability of additional internal water which is not part of the mixture water.
 The additional water being supplied by using relatively small amount of fine aggregate or polymer.

 The use of self curing admixture is very important from the point of view that water resources are getting valuable more over requirement of water for concreting is also high.

1.3 ADVANTAGES OF SELF-CURING (INTERNAL CURING)
 To overcome generated by both human and hydration.
 To eliminate shrinkage (most probably autogenous shrinkage).
 When properly applied, provides a premium-grade film, which optimizes water retention.
 Protects by reflecting the sun rays to keep the concrete surface cooler and preventexcessive heat buildup, which can cause thermal cracking.
 Furnished as a ready-to-use, true water-based compound. Produces hard, dense concrete, minimizes hair cracking, thermal cracking, dusting and other defects.
 Offers a compressive strength significantly greater than improperly or uncured concrete.
 Improves resistance to of salts and chemicals.

1.4 DISADVANTAGES OF SELF-CURING (INTERNAL CURING)
Most of these disadvantages are due to a lack of adequate research under field conditions, although many of the issues are currently being alleviated though the use of improved admixtures. First, increased quality control is needed in order to maintain the special properties desired. High-strength concrete must meet high-performance standards consistently in order for it to be effective. Second, careful materials selection is necessary. High quality materials must be used. These materials may cost more than materials of lower quality. Third, allowable stress design discourages the use of high-strength concrete. One solution is to use load factor and resistance design when using high-strength concrete. Fourth, minimum cover over reinforcement or minimum thickness of members may restrict the realization of maximum benefits. Fifth, available prestress force in a member may be inadequate to achieve maximum strength. Sixth, low water to cementitious materials ratios require special curing requirements. Finally, since serviceabilty conditions such as deflection can control design, increased capacity may not be fully utilized (Peterman).

1.6 SCOPE AND OBJECTIVE.
 The investigation is aimed to evaluate thebehavior of Self curing concrete by using Super Absorbent Polymer from 0% -1.0% on weight of cement.

 The following tests are aimed to study the behavior of Self curing concrete for M20,M30 and M40 Mix grades of Concrete.
 Compressive Strength.
 Split Tensile Strength.
 Stress-Strain behavior.

LITERATURE REVIEW

Present-day self-curing concrete can be classified as an advanced construction material. As the name suggests, it does not require to be cured in water. This offers many benefits and advantages over conve ntional concrete . This quality of concrete a nd reduction of autogenously shrinkage. The composition of Self Curing Concrete mixes includes substantial proportions of self curing agents and saturated recycled coarse aggregate and this gives possibilities for utilization of water inside concrete. The benefit from Self Curing Concrete can be expected when there is need for reduced construction time, quicker turnaround time in precast plants, performance and predictability. The use of Self Curing Concrete ensures quality and durability of concrete. In the following, a summary of literature, about the self compacting concrete and some of the projects carried out with this type of concrete, are presented.