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, ...
... middle of paper ...
...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.
(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.
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.
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,
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
[20] BS Part 116: 1983. Testing Concrete and determination of compressive strength. British Standards Institution ;
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.
Concrete is one of the most widely used construction material in the world. The reason for this is because concrete is strong, easy to make and can be molded into various shapes and sizes. Besides that, concrete is cheap, affordable and is readily mix.
There are numerous factors that determine the durability of a concrete. However, the main factor is the time needed to keep the concrete in a saturation state. Moreover, the reason a concrete normally undergoes early age shrinkage is that the concrete is being allowed to dry out too quickly. Figure 1 below shows an experimental result that is carried out to compare the strength of concrete by using different types of surfaces for 180 days. The surfaces are such as: -
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.
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.
Figure 1 Corrosion damage caused by chloride-contamination leaks in bridge deck expansion joints (Lam, 2011).
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.
Constituent materials are the fundamental materials required to produce concrete. The constituent materials of concrete consist of mainly three materials which are cement, aggregate and water, with admixtures included as addictive to alter the characteristics of the concrete (Scalenghe et al., 2011). “Cement is the chemically active constituent but its reactivity is only brought into effect on mixing with water” (Dhir & Yap, 1984). According to Bye (1999), in the industry, Portland cement, which was developed in 1824 by using calcium carbonate found in calcareous rocks, namely limestone or chalk and silica, alumina, and iron oxide found in sedimentary rock, namely clay or shale. Bye (1999) said that cement is produced by grinding the quarried limestone to powder form, blending it with water and heat with pulverized coal to drive out water at 100°C, carbon dioxide at 800°C and clinker at 1400°C, which is then cooled, grounded and mixed with 1%-5% gypsum to alter it fineness and goes through final grinding and the cement is ready to be distributed to the market. According to Sismondo & Sergio (2009), aggregate, which builds up the majority of the volume stability and the durability of the resulting concrete and is of lower price than cement, is always used to the maximum extend as possible in the production of concrete for maximum profit. Aggregates ar...
steel is widely used as a building material. it is because of its mechanical properties, ease and speed of construction and design simplicity. it is extremely easy to adjust or to extend to an existing structure constructed of steel by simply welding or bolting new steel pieces to the existing structure. and it will still give the structure the same amount of strength. structural steel has a wide amount of properties which suit different requirements which are weldability, ductility, strength and corrosion resistance. the extra feature of steel is that it will not break either, when met in contact with excessive load(s).