Effect of the content of micro silica and superplasticizer on the strength of concrete Prof. Dr. Gyawali Tek Raj1, Er. Bhattarai Devendra2 1Professor, School of Engineering, Pokhara UniversityKaski, Nepal 2Master in Structural Engineering, Department of Civil Engineering, Mid-West University, Surkhet, Nepal Online Published on 02 May, 2023. Abstract Concrete is the most popular construction material everywhere in the world. It is the second most consumed material, next to the water. From a historical point of view, in the middle of the 20th century, concrete with characteristic strength of 30 MPa was considered high-strength concrete and later in the 1980s, Concrete is said to be HSC when the compressive strength exceeds 50 MPa. Nowadays, HSC has sufficiently advanced such that concretes with compressive strengths of more than 120 MPa are commercially known as high-strength concrete that can be produced in laboratories. In this study, Laboratory tests were performed in the Lohara Khola bridge site and Ruma Khola bridge site with the bridge span 25-meter meter to investigate the ranging percentage of silica and superplasticizer on compressive strengths of the different mix proportions of concrete. A total of 12 trail mix proportions were used for the tests. Those were compared with the approved field applied test. Primary data were collected in laboratory tests whereas secondary data were collected from standard specifications for road and bridge-2073 and Is 10262: 1982. These data were analyzed by regression analysis for the comparison between micro silica and superplasticizer verse average compressive strength in MPa. From 7 days and 28 days of concrete cube tests, it was found the increasing trend of the compressive strengths while increasing the content of the silica. The relationship between the content of micro silica and Superplasticizer with the compressive strength was found almost linear. From the experiment results, the optimum content of micro silica and superplasticizer were found by 5% and 1.25% respectively by weight of cement for bridges, roads, and other structures. Among these different types of material used in concrete, micro silica, and superplasticizer have high strength than the rest of the other admixtures by doing 12 trial mixtures in a laboratory test in the field. Also, from several test results, the strength of concrete in the Lohara bridge site and Ruma bridge site have used normal concrete strength (NSC). In these sites, if micro silica and superplasticizer were used the strength of concrete may increase up to the level of moderate-high strength concrete which make the bridge high load-bearing capacity and more durable. Therefore, to make the bridge structures of higher strength and more durability, the use of micro silica and superplasticizer becomes necessary in the bridge construction sites. Top Keywords Superplasticizer, Concrete, Durability, Construction, Investigate. Top |