EXPERIMENTAL STUDY OF FLEXURAL STRENGTH OF REINFORCED CONCRETE BEAM INCORPORATING ULTRAFINE SLAG

Abstract: There have been enormous researches going on the use and utilization of industrial, agricultural and thermoelectric plant residues in the production of concrete. Production of high performance concrete (HPC) plays an important role with different pozzolanic materials like fly ash, condensed silica fume, blastfurnaceslag, rise husk ash etc. There has been increase in the consumption of mineral admixture by cement and concrete industries. This rate is expected to increase day by day. The presence of mineral admixture in concrete is known to impart significant improvement in workability and durability in concrete. The present paper involves the use of mineral admixture ‘ultrafine slag” as a cementitous material for cement and to evaluate the threshold limit of replacement of cement. Main aim of this work is to evaluate the flexural strength of High strength concrete by partial replacement of cement (0, 8, 10, 12, and 14%) with ultra-fine slag (Alccofine 1203) for M60 grade of concrete.OPC of 43grade from single source is used in this investigation. The properties of cement tested as per IS4031:1988 and found to conform various specifications of IS12269:1987. Locally available river sand is used as fine aggregate and also its specific gravity and fineness is determined. The addition of alccofine shows an early strength gaining properties with increase flexural strength of concrete. Keyword Alccofine-1203, Flexural Strength, Ordinary Portland cement, Plain Concrete Beams, Reinforced Concrete Beams.

A joint venture with Ambuja cement ltd and Alcon developers produces ultrafine slag with a brand name Alccofine.It is manufactured in the controlled conditions with special equipments to produce optimized particle size distribution which is its unique property.Alccofine 1203 and Alccofine 1101 are two types of Alccofine with low calcium silicate and high calcium silicate respectively. Alccofine 1200 series is of 1201, 1202, 1203 which represents fine, micro fine, ultrafine particle size respectively. Alccofine 1203 is slag based SCM having ultra fineness with optimized particle size distribution whereas Alccofine 1101 is a micro finer cementitious grouting material for soil stabilization and rock anchoring. The performance of Alccofine is superior to all the other admixtures used in India.

III. SCOPE OF THE WORK
The main and foremost objective of the present investigation is to evaluate the threshold limit of replacement of cement. Flexural strength of Reinforced cement concrete beam is carried out with partial replacement of cement by alccofine 1203. In this paper RCC beam of 500mm×100mm×100mm is used and investigation targets to determine the optimum percentage (0, 8, 10, 12, and 14%) of alccofine as a partial replacement of cement for M60 grade of concrete.

IV. EXPERIMENTAL WORK Materials
Ordinary Portland cement (OPC) of 43 Grade from single source was used in this investigation. The properties of cement tested as per IS: 8112:1989 The locally available river sand with specific gravity 2.66 and fineness modulus 2.5 was used as a fine aggregate. The compacted bulk density value is 1620Kg/m 3 .The crushed stone aggregate with maximum size 20mm having specific gravity and fineness modulus 2.68 and 6.7 respectively was used. Steel reinforcement used were 8mm dia bars as main reinforcement and 6mm dia bars as stirrups

Mix proportion
The mix proportion of M60 Grade concrete was designed based on the recommendation of IS10262: 1982 without alccofine. The identification of mix proportions and quantity of materials taken for 1m 3 of concrete mixes are given in table 3 and table 4. Concrete mixes were prepared with cement replacement of 0, 8, 10, 12, and 14% by alccofine.

Preparation of Test Specimen
The ingredients for various mixes were weighed and mixes prepared by using tilting drum type concrete mixes machine. Precautions were taken to ensure uniform mixing of ingredients. The specimen were cast in steel moulds of size 500mm×100mm×100mm. 2 bars of 8 mm dia as main reinforcement was used as main reinforcement shown in the Fig1 along with vertical stirrups of 6mm dia @150mm c/c.

V. CONCLUSION
The tests performed to check the Flexural performance of Alccofine as a cement replacement can be conclude as follows 1. Alccofine not only improves the compressive strength of concrete but also improves its flexural strength at much lower water cement ratio as compared to Controlled concrete. It also increases the workability of concrete at much lower w/c ratio due to ball bearing effect. 2. There is considerable change in flexural strength of RCC beam as compared to plain concrete beam incorporating same % of Alccofine. At 12% of alccofine there is maximum increase in flexural strength of RCC beam i.e. 22.5%. 3. Alccofine has better performance as compared to other slag materials and micro silica. It is helpful to make concrete workable. By replacing cement with alccofine there is considerable increase in workability of concrete without adding any plasticizers. 4. A control on deflection has been achieved in both the R/F & plain concrete beams when incorporated with alccofine without losing its strength. A higher loading was required to produce same amount of deflection in both cases. REFERENCES