This paper presents a detailed study on the use of marble powder (MP) as a binder in engineered cementitious composites (ECC). The study of the behaviour of ECC having partial replacement of cement of 5, 10, 15 and 20% with waste marble powder M45 grade was carried out and the effect on mechanical and physical properties of ECC is studied. Compressive test on cubes and flexural strength test on beams for 7 and 28 days was carried out. The result of this present investigation showed that the replacement of 5% of cement with waste marble powder attains maximum compressive strength.
Keywords: Engineered Cementitious Composites, Marble Powder, Compressive strength,
Concrete is a powerful, varied and cost effective material that has been used widely all over the world for construction. Concrete is widely used as a construction material having high compressive strength as compressive strength of concrete is the most important parameter to evaluate the construction quality of concrete but the concrete fails in tension. To carry the tensile load the concrete is usually embedded with steel reinforcement. This extra reinforcement is only needed for durability. Concrete is brittle in nature. Due to the brittleness of concrete, cracking is inevitable in concrete structures. Cracking can introduce chlorides, sulphates, oxygen, alkali or moisture into the concrete and stimulate further depreciation of the structure starts with the corrosion of the steel. To increase the strength and durability of the structure either the cracks that are formed should be repaired conventionally. A large number of concrete structures are suffering deflation during the early stage of service life such as bridge decks and pavements. In the civil engineering sector about half of the budget is spent annually on maintenance and repair because of untimely failure of structures, particularly 90% of the works focus on repair of cracks caused by reinforcement corrosion. It is common that structural performance has a great impact on the ingredients used. The civil engineering society is giving more attention to the performance based design concept for structures and gradually replacing the conventional dogmatic approach.
Recent studies focus on improving the brittle behavior of conventional concrete and have resulted in modern high-performance concrete namely bendable concrete also known as engineered cementitious composites (ECC). ECC is a mortar-based composite reinforced with specially selected short random fibers. It is a specialized type of concrete that can take the bending stresses. It consists of a special type of materials that makes it flexible. It exhibits the property of a ductile material instead of a brittle material which is shown by the conventional concrete. The compressive strength varies from 20-95 MPa. and flexural strength is 10-30 MPa. ECC therefore acts more like a flexible metal than a fragile glass leading to a wide variance of applications. PVA-ECC shows a strain hardening behavior with average strain at peak stress of approximately 5 – 6 %. In terms of matrix component it is very similar to normal concrete except it does not include coarse aggregate. Coarse aggregates are eliminated as they contribute to get negative effects on the ductile behavior of the compound. The materials used for ECC are ordinary portland cement, fly ash, silica sand, polyvinyl alcohol fibres, high range water reducing agent. The most elemental mechanical property of ECC has the ability to carry higher levels of loading after first cracking while undergoing large deformation. Due to the slip?hardening behavior of fibers, ECC can take increasing load that develops new cracks at another area. The cementitious matrix in ECCs consists of a Portland cement paste or mortar with the addition of fly ash, silica sand and PVA fibres with the additional use of High Range Water Reducing (HRWR) agent to impart good workability.
Extensive research has been conducted into the use of waste Marble as cement replacement in concretes. Encouraging results regarding the mechanical and durability properties of concretes incorporating MP have also been reported. Although a 10% MP substitution level gives better results than other replacement level. To date there has been no investigation into the use of marble powder in the production of ECC. Hence, this study sets out to assess the mechanical and physical behavior of ECC. ECC is prepared by replacing different levels of waste MP. ECC mixture was prepared by using ordinary portland cement ratio with fly ash partially replaced by 5, 10, 15 and 20% MP. Laboratory measurements included compressive test, flexural strength test and rebound hammer test.