Book Chapters
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28507
Browse
4 results
Search Results
Item Partial replacement of steel slag aggregates in concrete as fine aggregates (induction blast furnace slag)(Springer, 2019) Sundaramoorthi, S.; Hemalatha, T.; C, C.In this study, an attempt has been made to investigate the effect of partial replacement of conventional river sand with steel slag aggregate. The replacement of river sand by slag aggregate provides dual advantage of reducing disposal problems in steel industries and conserving the natural resources. In this study, slag aggregate originated from induction blast furnace has been used. The physical and chemical properties of slag aggregate evidenced the feasibility of using this material as a substitute for river sand. Total of three mixes made with Ordinary Portland Cement (OPC), cement replaced with fly ash and river sand replaced with slag aggregate have been considered for this study. The mix is designed for M40 grade. First mix (Control mix 0M0) made of OPC as a binder and 100% river sand, second mix (0M50) made of OPC and 50% slag aggregate and third mix (25M50) made of 25% OPC replaced by fly ash and 50% river sand replaced by slag aggregate. Mechanical and durability properties of all the three concretes are studied. It is found that the strength results of 0M0 and 0M50 are comparable indicating the suitability of using slag aggregate as an alternative for river sand. However, the third mix with fly ash replacement in binder showed reduced strength in comparison with control concrete. Hence, it is concluded that when slag aggregate is used as a partial replacement for river sand (50%), it is advisable to use OPC than the Pozzolanic Portland Cement (PPC). © Springer Nature Singapore Pte Ltd. 2019.Item Durability studies of polypropylene fibre reinforced concrete(Springer, 2019) Srikumar, R.; Das, B.B.; Goudar, S.K.A research programme was initiated to understand the durability of polypropylene fibre reinforced concrete (PFRC). PFRC was prepared with varying dosages of polypropylene fibre. Dosages used were 0.5–1.5% of cement content (by weight) with an interval of 0.5% and was added as a cement replacement to concrete mix. Durability studies were carried out by exposing the 28 days cured cubical specimens into marine environment having different pH levels (1, 4, 7, 10 and 13). The varying pH levels represent the pH of industrial effluents. The marine environment was simulated in the laboratory by adding 3.5% NaCl to the tap water. The specimens were exposed for the durations of 60 and 90 days. The resistance of concrete to marine environment was measured through compressive strength retention and ultimate bond strength retention. Scanning Electron Microscopy (SEM) studies were also carried out to understand the fibre dispersion. Test results show that compressive and bond strength increases with increase in pH and decreases with increase in immersion duration. Concrete with 0.5 and 1% fibre content are more desirable and have given higher residual compressive and residual bond strength when compared to concrete with 1.5% fibre content. © Springer Nature Singapore Pte Ltd. 2019.Item Durability studies on glass fiber reinforced concrete(Springer, 2019) George, R.M.; Das, B.B.; Goudar, S.K.In the present experimental study, glass fibers were used in varying dosages of 0.5, 1.0, and 1.5% of cement content (by weight) as partial cement replacement to cement in concrete mix. The effect of different dosage of glass fibers on the bond strength between steel and concrete in reinforced concrete was investigated. As a part of durability study, the combined effect of marine environment and varying levels of pH on the ultimate bond strength retention and compressive strength retention of glass fiber reinforced concrete was also studied. Durability studies were carried out by exposing the 28-day cured cubical specimens into marine environment having different pH levels (1, 4, 7, 10 and 13). The salt solution was simulated in the laboratory by adding 3.5% NaCl to the tap water. Calculated amount of sulphuric acid was added to salt solution to maintain pH of 1 and 4 in marine environment. Similarly, calculated amount of sodium hydroxide was added to salt solution to maintain pH of 10 and 13 in marine environment. The specimens were exposed to aggressive environment for a period of 60 and 90 days. As the fiber dosage increased the workability reduced, and 1.5% fiber dosage had the least slump value. The addition of glass fibers had very minimal influence on compressive strength of glass fiber reinforced concrete. The ultimate bond strength of concrete increased due to the addition of glass fibers. The increase in ultimate bond strength was confirmed through SEM images which shows proper bonding between cement paste and glass fibers. As for as the exposure studies are concerned, 1.0% fiber dosage of glass fiber reinforced concrete had shown better compressive strength and ultimate bond strength retention compared to 0.5 and 1.5% fiber dosage. The pH of the marine environment has a decisive influence on the compressive strength retention and bond strength retention. Exposure to marine environment with pH 1 suffered severe loss in compressive strength and ultimate bond strength with very low strength retention values. However, exposure to marine environment with pH 10 and 13 had minimal strength losses with higher values of compressive strength and ultimate bond strength retention. Increase in exposure period to aggressive media leads to decrease in compressive strength and ultimate bond strength, but the strength retention values for glass fiber reinforced concrete were comparatively better compared to control concrete. © Springer Nature Singapore Pte Ltd. 2019.Item Strength Behavior of Rammed Earth Stabilized with Metakaolin(Springer, 2020) Thiviya, S.K.; Krishnan, A.G.; Kalathuru, M.; Sharma, A.K.; Kolathayar, S.Rammed earth is an ancient construction technique practiced in India and in other parts of the world. The ancient traditional technique was of the un-stabilized method but incorporating suitable stabilizing materials will improve the strength of rammed earth construction. The main objective of the present study is to assess the behavior of the rammed earth with metakaolin. The suitability of the soil was tested based on sieve analysis and followed by mini compaction tests; optimum moisture content for the rammed earth construction for the selected soil was fixed for different proportions of binders with the soil. From the compaction results, the binder content was fixed for stabilization of rammed earth. The unconfined compressive strength of the sample was found for the samples at 7, 14, 28 days of curing, and microstructural studies of the samples were performed. The compression strength of rammed earth cubes was tested and also the durability of the cubes was determined by the spray erosion test. © 2020, Springer Nature Singapore Pte Ltd.