Report On Chemical Composition And Structure Of Csh

“Roman concrete (opus caementicium), like modern concrete, is an artificial building material composed of an aggregate, a binding agent, and water. Aggregate is essentially a filler, such as gravel, chunks of stone and rubble, broken bricks, etc. Binding agent is a substance which is mixed with the aggregate wet (water added) and solidifies when it dries, or "sets." Many materials, even mud, can be a binding agent, and used to make, what we generally call, mortar. Historically lime or gypsum, mixed with rubble stones, have been used as binding agents in making a strong mortar” (Roman Concrete).

Cement is made from a mixture of limestone, sandstone, ash, chalk, iron, and clay. Researchers discovered the Roman concrete contained aluminum tobermorite, a rare mineral that adds extra strength. Cement was used by plebeians because they were the farmers, craftsmen, laborers, and soldiers of ancient Rome.

Glass ionomer cement[GIC], invented by Wilson and Kent, has been used as a dental restorative material for more than four decades and its properties are constantly improved to overcome its shortcomings. The unique properties of GIC include direct adhesion to tooth and base metals [1], anticariogenic properties [2], thermal compatibility with tooth enamel and dentin, minimized microleakage at the tooth–enamel interface, biological compatibility, and minimal cytotoxicity. The disadvantages of GIC such as Brittleness, low tensile and flexural strengths has limited its use to low stress-bearing sites such as Class III and Class V cavities [3]. Various studies have been done to improve the properties of GIC by incorporation of materials such as bioglass, CPP-ACP etc. In our study we have incorporated chitosan to enhance the properties of GIC.

Roman building using cement (Labate, 2016) dates from the third century BCE. Cement was used with crushed bricks and rock to produce concrete used for building. The cement was made from volcanic dust (pozzolana), lime (calcium oxide) or gypsum (calcium sulphate). This mixture reacts when mixed with water, binding the concrete into a permanent, strong, impermeable structure. The Roman engineers discovered that the use of cement in their mortar dramatically increased its strength. Special types of cement were discovered and used for under-water structures like harbors and bridge piers. Roman workmen perfected the skill of building with concrete, some of which, like the Parthenon, are still intact and beautiful to this day. During the first century CE, Rome had a “Concrete Revolution”, many concrete buildings being built as skill developed.

Builders in Greek cities on the coast of Turkey (and in particular Pergamum) evolve cement in about 200 BC as a structural material, in place of weaker mortars such as gypsum plaster (used in Egypt) or bitumen (in Mesopotamia). The secret of the new material is the lime which binds sand, water and clay.

However: concrete-like structures were built in southern Syria and northern Jordan in around 6500 BC (Gromicko.& Shepard, n.d.); and ancient Assyrians and Babylonians are known to have used a form of concrete with a bonding agent of clay, while Egyptian concretes used lime and gypsum for bonding (Encyclopaedia Britannica, n.d.). Some Greek cities on the coast of Turkey also used concrete around 200 BCE using lime (Gascoigne, 2001).

The warm water was added to the dehydrated mixture of table salt, sand and the copper sulphate. The solution changed to a visibly blue homogenous colour. The sand and some of the copper crystals that did not dissolve remained at the bottom of the beaker. A small amount of copper sulphate residue was left in the collection funnel. The temperature of the solution was too high for the mixture to bind and recrystallize; Ethanol was added to the mixture to lower solubility. The beaker was then placed in a cooler for duration of 10mintues to decrease temperature and increase the rate of recrystallization. When the beaker was removed from the cooler it was still visibly blue indicating in was not a complete recovery. Recovered copper sulphate pentahydrate crystals were solid, multi edged and uniform in assembly. High level of purity.

Silica gel is silicon dioxide (SiO2) manufactured as small round beads with a large pore surface area (Figure 19). The water contained in the gas vapor is adsorbed by the desiccant at relatively low temperatures.

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

In this step also consider the durability of the concrete and the unpredicted external load. This research uses metakaolin and silica fume as the main materials.

Calcium Hydroxide, or simply known as hydrated lime serves many functions like reducing the acidity in soil or lakes, an additive in cement, a raw material for mortar, cleaning agents.

White cement is the key ingredient in decorative concrete. New coloring agents and admixtures help create beautiful structures and landscapes.

By the use of silica fume it’s improve the properties of fresh and hardened concrete.

Cement is the binding material that holds the concrete together, and is therefore a basic need for every construction involving concrete or biding of basic blocks like bricks. Also concrete is the second most consumed material after water, with nearly 3 tonnes used annually for each person in world.

The function of cement is for isolating production zone and to provide support for the casing [11].Portland cement is made up of calcium oxide (CaO), silicon dioxide (SiO) and water (H2O) which the composition of calcium carbonate is around 75-80 wt% and 20-25 wt% of clay [7],[14].. Compressive strength of Portland cement is developed through hydration. Hydration is chemical reaction between water and cement compound. The rheology and early strength of cement is developed from reaction of aluminate compound at the beginning of hydration. Rate of hydration can be control by adding gypsum. It is for preventing the premature hardening of cement. Gypsum will react with aluminate and hydroxyl ion to form ettrigate. Ettrigate will prevent hydration process by forming needle shaped crystal on the aluminate and creating induction period [11].