Experimental Investigation on Corrosion Identifying and Enhancement of Existing Concrete Structures
Authors: Mr. B. Jose Ravindra Raj, R. Pradeep Raj
Abstract
Corrosion on structure is one of the biggest challenges faced by the civil engineers. Since repairing at rehabilitation requires costly treatments without considering corrosion damages on the structures. Identifying the corrosion on the concrete structure requires more research to solve effectively. A majority of concrete structure is shows signs of degradation due to the corrosion of the reinforcement in the presence of chlorides. In some cases, the degradation is visible with in few years of construction completion. Despite the fact that the concrete structure is particularly suffer premature degradation due to corrosion, due to poor construction quality as a result of poor workmanship. Inadequate standards based on prescriptive measures and poor design as a result of insufficient information with regards the parameters that influence the degradation process. While standards are gradually improving, with the tendency to become performance based in future, much information is needed to assist the designer in the decision making process. A durability model for the reinforced corrosion, based on the Half-Cell Potential Meter Apparatus with different environment. A model is prepared and then the model in tested by immersing in tap water with three known PH value (PH 7.5, PH 9, PH 13 ,) The corrosive effects of tap water, after a certain period of time is calculated by the model is taken out and the by measuring corrosive factors, then these factors are Compared with the actual structures. After this comparison to enhance the life time of structures, chemical coating is applied to concrete models and the effects are studied. After such studies the most successful chemical coating can be applied to the concrete models, which in turn increases the life time of buildings. This project would propose the effective and cost saving chemical coating.
Experimental Study on Strength & Durability Characteristics of Special Concrete By Using Phosphogypsum With Steel Fibre
Authors: Prof. B. Jose Ravindra Raj, E. Subiar Ahamed
Abstract
Most Concretes produced today contain materials in addition to Portland cement to help achieve the strength or durability performance. These materials include fly ash, silica fume and ground-granulated blast furnace slag used separately or in combination. In this project we used phosphogypsum as admixture to improve the performance of concrete. It is a waste material obtained from fertilizer manufacturing. Also, steel fiber is introduced to increase the tensile strength of concrete. The grade of concrete used is M20 & M25. For both the mixes, phosphogypsum is added as 0%,15%, 20% & 25%. The steel fiber is kept constant for all the mixes as 50kg/m3. The material testing’s done to arrive the mix proportion. The fresh concrete properties are studied. Harden concrete properties of concrete like compressive strength, split tensile strength are done and the results are enclosed in this report. It was found that the concrete with 15% phosphogypsum & 50kg/m3 shown good performance both in fresh and harden state.
Experimental Study on Enhancement of Concrete Using Marble Dust as Partial Replacement of Cement
Authors: Prof. B. Jose Ravindra Raj, A. R. Mohamed Asif
Abstract
According to global cement magazine, each ton of cement produced releases about the same quantity of Co2. During the production of cement energy is consumed and consequently Co2 is emitted to the atmosphere. There is a need to understand the nature of energy utilization in embodied energy in buildings and maintenance, since developing countries like India have limited energy resources vis-a-vis the large population. Leaving the waste materials to the environment directly can cause environmental problem. Hence the reuse of waste material has been emphasized. Waste can be used to produce new products. Green concrete concept of thinking environment into concrete considering every aspect from raw materials manufacture over mixture design ,construction, and service life. Green concrete is very often also cheap to produce ,because for example ,waste products are used as a partial substitute for cement ,charges for the disposal of waste are avoided energy consumption in production is lower ,and durability is greater. The advancement of concrete technology can reduce the consumption of natural resources and energy sources and lessen the burden of pollutants on the environment . To overcome the above, first of all selecting the right material from natural resources and energy sources and lessen the burden of pollutants on the environment in our surrounding area to be thoroughly studied and collected. For this study, we have taken the large amount of “marble dust” generated in natural stone processing plants which have an important impact on the environment and humans around our nearby districts . This study is to investigate the strength of concrete using the “marble dust” as partial replacement of cement. The specimens are casted with marble dust as partial replacement of cement varying from 0% to 25%.The specimens are subjected to cube test , cylinder test, flexural test, pull out test and durability test . The strength and characteristics shall have been studied with the conventional concrete.
On r∗mwg - Continuous Multifunctions in Topological spaces
Authors: A. Ponsuryadevi, R. Selvi
Abstract
In this paper, we introduced and studied basic properties of weaker form of multifunctions such as upper and lower ∗ wg-continuous multifunctions. We obtain some of its characterizations with totally ∗ wg-closed graph and strongly ∗ wg-closed graph in Minimal Structures.