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How too install a Stamped Concrete Patio

Concrete begins life as a fluid mixture of cement, water, sand and gravel can be molded into molds or shapes and harden to create the necessary components of a concrete structure. Concrete hardening and hardening is caused by a chemical reaction between Portland cement and water. This can be demonstrated by adding a small amount of cement to the water containing an indicator. The rapid development of a blue color reflects the release of hydroxyl ions from the solvent cement. The chemical reaction between cement and water is called hydration. Dissolved cement increases the levels of calcium and silicon in the solution when dissolved species concentrations reach critical levels. New solid products are formed by a precipitation reaction. This is a sketch of cement grains suspended in the water. Solid hydration products form coatings around the cement particles and progressively fill the gap between the time the coatings begin to occur. There is a constant development of strength when coatings are growing together. The amount of resistance obtained by mixing the cement and the water depends on the efficiency of the space between the grains, the concrete hardens in a few hours, but the hydration continues for weeks or even years after the setting up . Here is an image of cement particles before exposure to water. Dry cement is a fine powder and the particles are not fixed to each other after the cement has been mixed with water and allowed to stand.

The picture is quite different. Now the particles are grouped together and attached by a solid material that ensures structural integrity. Scientists at the National Institute of Standards and Technology learned to simulate the hydration of cement on a computer using computer simulation. Hydration is accelerated to occur in minutes rather than days before. The hydration simulation particles of the cement are arranged on the screen of the computer. The computer determines the regions of the particles that can dissolve in the water, the pieces of dissolved cement diffuse into the water at random, and react to form solid phases according to certain rules. After a cycle of dissolution, diffusion and precipitation, the computer goes to another cycle, as this process repeats, the microstructure develops. Building bridges between particles that reinforce hardware computational simulation has proven useful as it allows researchers to test conditions and perform measurements that are difficult to perform in real life. At the end of the hydration simulation, the structure of the hardened cement paste is very similar to that observed under the microscope. Hydration is an exothermic process that generates heat through chemical reactions. The hydration process can be easily monitored by monitoring the heat production that accompanies the reactions. This is done by sipping the mortar of a batch of concrete and weighing it into a bottle that is placed in an insulated container.

A thermistor is the one incorporated in the fresh mortar, the output of the thermistor can be recorded by a computer. The results of this experiment can be plotted in the form of a temperature curve as a function of time. The area under the main peak may be related to the early development of force. The initial dissolution of Purdue cement is a short evolution of the heat indicated by the first peak of the calorimetry curve. After initial dissolution, the hydration products are rapidly precipitated on the surface of each particle ofcement, the layer acts as a protective barrier and temporarily delays the subsequent dissolution of the particle. This slows down the reaction for several hours and is called the dormancy period. The existence of the dormancy period allows the concrete to be transported to the construction site and placed and finished in forms. The end of the dormancy period is when the cement begins to react more quickly with water as new hydration products are formed. Scientists use measurements of other properties to monitor concrete placement, and hardening researchers often need to know which part of the cement has been hydrated. The degree of hydration can be estimated by heating a sample of cement paste and measuring the weight loss as a function of temperature. Using thermal gravimetric analysis equipment, the free water in a sample is rinsed at 105 degrees Celsius at 105 degrees. The sample is dry but retains its strength. The water involved in the hydration reactions is chemically combined with the cement, it can be removed from the sample by heating at 1000 degrees to 1000 degrees. All original mixing water was removed from the sample. The degree of hydration is calculated from the weight of chemically combined water.

A typical cement paste hardened under humid conditions will reach a degree of hydration of about 80% in 28 days. The electrical properties of cement or mortar samples can be tracked over time, resulting in changes in electrical resistance. The electrical properties of this cement sample are measured using metal tracks and measuring, resistance and impedance equipment. This graph illustrates how the resistance of electricity through cement increases as cement hydrates at an early age. The water easily conducts the current through the sample, but when the hydration products fill the open spaces in the sample, the electric current can not pass as easily. In this way, the electrical properties can be related to the degree of hydration. The strength and impedance of cement is a research topic that could one day change the way we test fresh concrete on the ground. The fluid properties of concrete are very important in the field because a quality construction requires adequate consolidation. The standard sag test provides a rough measure of concrete workability. This test is widely used because it is easy to drive in the field. The properties of fluids are also studied in the laboratory, as the flow of cement changes as hydration progresses, such as viscosity, and the initial resistance to flow is used to characterize the materials. liquids. Water is a liquid with low viscosity and low initial flow resistance, but concrete, mortar and fresh cement paste have a much higher viscosity than water. Vibrations are often used to overcome this resistance in concrete in the laboratory. The fluid properties of the cement paste can be measured with this meter. Researchers are using larger equipment such as this thermometer to measure the properties of mortar and concrete. The equipment can be used to measure the initial resistance to flow, so-called yield strength at the time of hardening, the yield strength begins to increase and the ability to flow is lost. . Researchers are interested in flow characteristics to understand how the hydration process stiffens the cold, the concrete and leads to the placement of stamped concrete patio nh.

The hydration rate can be controlled in several ways. Factors such as temperature, type of cement and blends affects speed. One of the most important variables is the ambient temperature. High temperatures accelerate hydration so that adjustment is faster as well as strength and development. The opposite occurs when the temperature is lowered. A good rule of thumb is that for every temperature change of 10 degrees Celsius the hydration rate is changed by a factor of two. For example, an increase in temperature from 20 degrees Celsius to 30 degrees Celsius double. The hydration rate makes it important to remember that as the weather cools, the concrete cures slowly and needs to stay in shape longer. Hydration of concrete can also be controlled by using different types of cement to counter the effects of high or low temperatures in the field. For example, the use of Type 3 cement types neutralizes cold temperatures because they hydrate faster. There are also special chemicals that regulate hydration. Accelerators Can be added to the concrete for hydration to be faster, hardened, delayed, slow, hydrated. These materials are widely available. In summary, hydration is a chemical reaction between the cement and the water that binds the cement particles and the aggregate in the concrete in a strong mass. One of the important advantages of concrete over other building materials is that it is mixed and formed at the site and that it can take very large and flexible Shh. The ability of the concrete to quickly gain strength makes it a valuable material for roads, buildings, bridges and other important structures.

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Casa Cook Kos Hotel / Mastrominas ARChitecture

Photos © Georg Roske

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