temperature, humidity and wind play a vital role in the quality and strength of hardened concrete. The following points must be ensured at site to produce the concrete of required strength: 1. In order to achieve full compaction and maximum density, it is necessary to use a mix with adequate workability. 2. To obtain maximum strength of the concrete a driest possible concrete should be produced and shall be compacted 100 %.
(Lintern, Roach, and Chen, 2002) 1.4.3. Laminar Calcrete This develops as indurate sheets of carbonate overlying hardpan Calcrete or other hand surfaces. (Wright and Tucker, 1991). The laminae can be as thinner than 1mm and the total thickness of this Calcrete is normally even lesser than 250mm. this may occur as a thick layer without any underlying hard surface.
Concrete is the composite mix of cement, aggregates, sand and water. Concrete gets hardened like stone on mixing water with cement and aggregates. Concrete have two type ingredients namely active and inactive. The active group consists of water and cement. The inactive part consists of sand and coarse aggregates.
The strength of concrete varies according to the proportions of its constituents. Concrete gains its strength over time as it hardens by means of setting, where by cement undergoes a chemical reaction known as hydration. It can set and harden underwater hence it can be used as foundation material. Its hardening process can be enhanced by curing. Due to its workability it can be formed into different
To study the effect on strength of standard mix of concrete by addition of marble powder in it. 3. To study the effects of percentage replacement of sand by marble powder on strength of concrete. 1.5 Scope of study The research will cover studying the setting time of marble waste powder blended Portland cement and workability, compressive strength, flexural strength and split tensile strength of concrete produced by marble waste powder blended cement, and marble powder blended sand. Throughout the investigation, the research is limited to marble powder obtained from the factories of Indore which process marble.
The correlation between the NDT and the structure strength can be established. The correlations are particular for a certain type of concrete and must be used with caution. Concrete properties can vary considerably depending on the nature and proportions of its materials, the construction methods and the loading and environmental conditions. In order to prevent and control the concrete deterioration, it is interesting to establish continuous monitoring strategies, which might be a powerful tool to increase the service life of concrete. This implies the development of control methods which are able to determine the quality and the condition state of concrete.
A major component of concrete is cement, which has its own environmental and social impacts and contributes largely to those of concrete. The cement industry is one of the primary producers of carbon dioxide, a major greenhouse gas. Concrete causes damage to the most fertile layer of the earth, the topsoil. Concrete is used to create hard surfaces which contribute to surface runoff that may cause soil erosion, water pollution and flooding. Conversely, concrete is one of the most powerful tools for proper flood control, by means of damming, diversion, and deflection of flood waters, mud flows, and the Concrete dust released by building demolition and natural disasters can be a major source of dangerous air pollution.
This low permeability reduces the effects associated with the absorption of chemicals which include the corrosion of steel reinforcement and erosion of the concrete itself. This increases the repair cycle and lifespan of the concrete and the structure as a whole, while also creating the conditions that allow certain chemical reactions to occur that will help to heal or fill the cracks of the concrete
When such water is used as mixing water in concrete, the reduction in compressive strength is generally less than about 10 per cent. Waste waters from paint factories, coke plants, chemical and galvanizing plants may contain harmful impurities. It is advisable to test any waste water that contains even few hundred parts per million of unusual solids before using it for mixing concrete. One way of using sewage containing large organic matters (say 400 ppm) is to dilute it in a good disposal system to reduce the concentration to about 20 ppm or less, an amount too low to have any significant effect on concrete
CHAPTER 1 INTRODUCTION 1.1 GENERAL Concrete is an extraordinary and key structural material in human history. Concrete holds the credit of being the most widely utilized tailored or man- made material in the construction industry and will hold good for the years to come. This credit goes to the properties of concrete like excellent strength, durability, less maintenance costs and use in many structural applications. But in the recent years the concrete industry is facing a big challenge mainly due the cement which is a vital component. International Energy Agency states that cement production accounts for 7% of total global CO2 emissions.