1.1 BACKGROUND OF STUDY
In Malaysia, corrosion of the steel in the reinforced steel due to the chloride ingress is one of the most common environmental attacks that lead to the deterioration of concrete structures. Corrosion related damaged to the bridge decks, parking garages marine structures and industrial plants results in huge spend money annually to repair and maintain. This durability problem has received widespread attention in recent years because of its frequent occurrence associated high cost of repairs.
This study will focus on the chloride penetration to the concrete in various type of the strength and days of the concrete. This study is examined the effect of chloride to the concrete strength and durability of concrete on various type of concrete mixture proportion. Different type of concrete proportions mixture will give the dissimilar result of the experiment.
1.2 PROBLEM STATEMENT
The famous problem in our country is the major forms of environmental attack is chloride ingress which lead to the corrosion of the reinforcing steel and a subsequent reduction in strength serviceability and the aesthetics values of the structure. This may lead to preliminary repair or replacement of the structure.
Previous study about the Ordinary Portland Cement (OPC), High Performance Concrete (HPC), And Ultra High Performance Concrete(UHPC) there are different result about the penetration of chloride ions to the specimen. This because, the reinforced concrete are exposed to harsh environment yet often expected to last with little or no maintenance for a long periods of time. The lacking maintenance of the concrete may cause this problem become worse and the concrete may not suitable to used.
To overcome this problem, ...
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...ross the cell. The negative terminal is connected to the electrode in the reservoir with the NaCl solution and the positive terminal is connected to the electrode in the NaOH solution. The negatively charged chloride ions will migrate towards the positive terminal. The more permeable is the concrete, the more chloride ions will migrate through the specimen, and a higher current will be measured. The current is measured for 6 hours. The area under the curve of current versus time is determined, which represents the total charge or Coulombs passed across the specimen. The Coulomb values are used for classifying the concrete as follows.
While for the ultra pulse velocity test (UPV), after the sample undergo the RCPT test, the UPV test will began. Each sample are test by repeating the reading in three times. The reading are record and will be analyse using the formula.
Biezma, M. V., & Schanack, F. (2007). Collapse of steel bridges. Journal of Performance of Constructed Facilities , 398-405.
(Mazzassa – Lea's science). Calcium silicate hydrate is the fundamental result of lime-pozzolan response. Calcium aluminous hydrate, hydrated gehlenite, calcium carboaluminate, ettringite and calcium aluminous monosulfate are a percentage of alternate items that outcome from the lime-pozzolan response notwithstanding calcium silicate hydrate. (Admixtures for cement T.erdogan). The hydration between slica of pozzolans and calcium hydroxide are given by mathematical statement.
Most people may not realise but concrete plays a vital part in our lives daily. It shapes and creates the built environment in which we are surrounded by, such as schools, bridges, roads, housing, hospitals, dams and so much mores. Concrete is the most used man made material in the world, averaging around 3 tonnes annually for each person. In comparison with other building materials such as wood, steel, plastic and aluminium, over twice as much concrete is used globally than any of these materials. It is the material choice of most purposes due to its strength, durability, thermal mass and its cost.
Cement hardens when it comes in contact with water. Hardening is not a drying process and can very well take place in water. Heat speeds up the setting and hardening of cement and cold slows it down and can even completely stop the processes. In order to crystallize or hydrate, cement requires a quantity of water equal to 25% of its weight. But in order for it to be laid and remain sufficiently workable, twice this amount is usually required. However, too much water can reduce the strength and durability of the concrete. The paste (i.e. the mixture of cement and water) acts both as a lubricant and an adhesive. Hardening does not start as soon as cement and water are mixed, but after a certain length of time known as the “initial set time” during which the concrete can be mixed, transported, laid and vibrated. (All Public Works,
[17] BS 4550-3.4:1978. Methods of testing cement, Physical tests, Strength tests. British Standards Institution ; 2007.
Bridge routines and in-depth inspections were put into place after the collapse to prevent another disaster (Silver Bridge Collapse). Engineers are now more informed about corrosion and how it affects the materials bridges are made out of. With increased knowledge, the quality of structures have improved and can now withstand all forms of corrosion and stress (Silver Bridge Collapse). The Silver Bridge was never rebuilt due to the stress and devastation to the
Manufacturers depend on steel to protect us. Because of its strength, durability and dependability, steel is also the key to recycling all automobiles at the end of its long life as it is continuously recyclable and contains recycled steel.
In these cases, such as building a reservoir, a huge number of concrete trucks are generally brought in in a caravan, and they pour their concrete into the forms that have been constructed onsite. In some cases, this order will put a concrete plant out of commission for a period of time due to the demand, and as such it must obviously be coordinated ahead of time.
In this report, we will introduce and illustrate on precast concrete, pre-stressed concrete, ready-mix concrete, reinforced concrete, terrazzo and Urbanite in details.
Figure 1 Corrosion damage caused by chloride-contamination leaks in bridge deck expansion joints (Lam, 2011).
The length of time for which the concrete mixture remains plastic predominantly depends on the …………………………………………………
...n most part if steel were to be used in a Type I structure, it would be to reinforce the concrete because concrete is strong in compressive strength but weak in tensil strength. If there is any exposed steel, it is fire proofed with a fire retardant. Mainly the fire hazards that firefighters have to face in these structures are usually because of human error during the construction of the buildings or when occupants are occupying the building. In a construction sites welding, cutting, plumber’s torches, electrical wiring, and heaters all pose a fire hazard. The other risk of this type of building would be of a collapse of the concrete walls or floors during construction.
High performance concrete is a concrete mixture, which possess high durability and high strength when compared to conventional concrete. This concrete contains one or more of cementious materials such as fly ash, Silica fume or ground granulated blast furnace slag and usually a super plasticizer
Ordinary Portland cement available in local market of standard brand was used in the investigation. Care has been taken to see that the procurement made from a single batch and is stored in airtight containers to prevent it is being affected by atmospheric, monsoon moisture and humidity. The Cement is tested for its various proportions as per IS 4031-1988. The specific gravity was 3.10 and fineness was 3200 m2/Kg. The details are given in Table 4.1.1. The cement confirms to 53 Grade.
Some of the data of losses due to corrosion follows. In the United Kingdom the Paint Research Association has estimated that metallic corrosion costs developed countries some up to four per cent of gross national product (GNP) annually. In the UK this would equal about £30 billion. In the United States, various reports put the cost of corrosion slightly higher at four to five per cent, equating in that country to about US $300 billion, of which it is claimed that around one-third could be prevented. In India approximately 5% of the GDP is lost due to corrosion, of which again it is claimed that around one-third could be prevented.