Advantages And Disadvantages Of Expansive Additives

For the Synthesis of Alum lab my lab group and I took 1 gram of aluminum foil and broke it into small pieces. Next we added 25 mL of 3M KOH solution. Once the foil was dissolved we filtered the solution through a Buchner funnel with filter paper sealed inside with water. As the solution was filtering we applied a vacuum filtration to the Buchner funnel to expedite the filtering process. Once it was completely filtered my lab group poured the solution into a beaker and covered the beaker with parafilm. We then waited overnight to allow the crystals to form inside the beaker. Unfortunately, we did not produce any crystals overnight so we borrowed some from another group. Once we obtained the crystals we had to stir them in a beakers to make more form other than just the ones we received. After we rinsed the crystals with half ethanol and half water mixture. Once they were dry we determined the mass of the crystals with a balance.

The paper describes the conditions and mechanism of hydrate formation and consequently relates to the prevention of hydrate formation. Benefits and drawbacks of each inhibition system are

In the following decades lime and cement injections were the most widely used methods for stabilization of clay. However, hydration starts while water and cement are mixed But when water reaches cement, hydration happens and hydrated calcium silicates (CSH), aluminates (CHA) and lime (Ca(OH)2) would be generated which would and cause a rise in pore water pH. In 1971, [5] found the reactivity of clay minerals with acids and alkalines and afterward the usability of other chemicals other than lime and cement was investigated. Also, for reducing the stabilization costs, replacing cement with low cost waste materials has been studied. Moreover, the effect of portland cement manufacturing on amount of greenhouse released in the atmosphere and consequently, global warming has been another reason for finding a

Aggregate is one of the basic constituents of concrete. Its quality is of considerable importance because about three-quarter of the volume of concrete is occupied by aggregates. One of the physical properties of aggregate that influence the property of concrete is the grading of aggregate. The grading of aggregate defines the proportions of particles of different size in the aggregate. The grading of fine (size < 5 mm) and coarse (size > 5 mm) aggregates are generally required to be within the limits specified in BS 882: 1992.

Properties of concrete are governed not only by the properties of its ingredients (cement, water, sand, and coarse aggregate) but also, to a great extent, by the relative proportions of these ingredients. The proportions must be so selected as to produce a concrete mixture of desired workability, strength, durability, and economy.

2. When pressure exceeds the tensile strength of concrete, scaling can result if entrained-air voids are not present to act as internal pressure relief valves.

In general, the durability of concrete covers directly on the ease or difficulty of fluid transport within the concrete, and classified as a concrete or too little permeable. The main transport agent fluid is water in the concrete, which may be pure or contain aggressive agents, such as dioxide carbon and oxygen. The displacement of these elements will depend on the concrete structure hydrated cement paste (Neville, 1997). THE Concrete durability of recycled aggregates also it depends on the ease or otherwise of transport these fluids. Olorunsogo and Padayachee (2002) studied properties related to the durability of concrete as the conductivity of chloride ions, sortividade permeability to oxygen and water, containing percentages of 0%, 50% and 100% replacement of natural aggregates by recycled. The results showed that the durability decreases increases in proportion as the percentage of replacement for all properties evaluated. However, these properties improve with increasing age and with percentages of 50% recycled aggregates in the

Concrete is a important product that is used in the construction of building and infrastructures. A concrete has to have strength, durability and quality to make a strong and stable infrastructure. This study will tell us does ACC concrete mix is a very good product in the market. Does it pose a strong contender to its competitors in the current market and does the brand image of ACC ltd. plays any role in purchasing of its products.

In order to produce High Performance Concrete, cement which containing as little C3A as possible should be used during manufacture process. This is because the lower amount of C3A, the easier to control the rheology properties on cement. Other than that, the cement-super plasticizer compatibility problems can also be reduced. Finally from strength point of view, this cement should be finally ground and contain an appropriate amount of C3S.

INTRODUCTION When cement is mixed with water in order to prepare concrete, the hardened concrete formed after hydration is not a solid mass but a porous material. There is formation of pores due to water which is initially added. Water occupies some fraction of the total initial volume and after the hydration of cement water is held physically, chemically or is adsorbed on product after hydration. This leads to formation of different types of pore structure inside the hydrated cement. CLASSIFICATION OF PORES STRUCTURES IN HYDRATED CEMENT 1.

Abstract. Considerable network of transportation infrastructures such as highways, rails, and so forth are key providers to economic growth and productivity of countries. Consecutively, Reinforced Concrete (RC) is the predominant construction materials in constructing many of these infrastructures. RC is a unique construction material which allows flexible design layouts and offers safe bending and torsion to satisfy design requirements. However, being exposed to harsh environment and contamination such as salts, acid rain, distilled water, carbonation, sulphur and so on are the reasons for deterioration, thus significantly impacting the performance of these structures. Furthermore, the deterioration of these structures is not only a

Concrete is a vital construction material and establishing the compressive strength is key as the ability to maximise the compressive strength will enhance a structures lifespan. Mortar is formed through the mixing of cement and water before being cast to harden. When the cement and water is mixed the process of hydration occurs forming a paste which then hardens. Once concrete is cast and dries the presence of curing time is important. Not all chemical reactions occur quickly, therefore by curing concrete in water for several days it allows all reactions to complete. Therefore allowing concrete to cure for up to 28 days should ensure that the compressive strength is maximised and it should meet industry standards.

The production of Portland cement is high-energy consumption and produce large amount emission of CO2. Previous research indicates that 0.98kg of CO2 will be created by production of 1kg of Portland cement, including 0.53g from decarbonisation, 0.33g from burning process plus 0.12g from generation of electricity power required. Therefore, for every ton of cement produced, an approximately equal amount of carbon dioxide is relapsed in to atmosphere [2阿三]. The world cement industry contributes 7% of total CO2 emission [3]. This leads to the research of seeking more environmental friendly cements. One of these alternative materials is alkali-activated slag (AAS) cement. Comparing with Ordinary Portland cement (OPC), the AAS has is own advantages. Firstly, it uses ground granulated blast-furnace slag (GGBS) as the binder material of concrete, which is a by-product from industry production. Secondly, AAS cement has low energy cost and low GHGs emissions. Finally, AAS concrete has excellent engineering

A preliminary investigation of strength and durability properties of a low-cost concrete-like system made of pH-adjusted fluorogypsum (FG), class C fly ash (FA), and type II Portland cement (PC). A series of compressive strength tests and volumetric expansion measurements were conducted on specimens after 28 days of curing. The experimental results were used to develop response surface models (RSMs). These RSMs can be used to predict accurately compressive strength and volumetric expansion as functions of the relative content, in dry weight, of different components. The RSMs

In civil engineering construction, one of the most determining factors for the stability of a structure is the maximum strength attained by concrete after 14 and 28 days. As such, it is often critical for an engineer to test a particular test concrete cylinder mix for the ultimate compressive strength and then compare it with the design strength before allowing the concrete mix to be replicated in large quantities. The factors that affect the ultimate compressive strength of concrete include the amount of aggregates and the ratio of water to cement.