What is meant by racial segregation?
Racial segregation, the practice of restricting people to certain circumscribed areas of residence or to separate institutions (e.g., schools, churches) and facilities (parks, playgrounds, restaurants, restrooms) on the basis of race or alleged race..
What is green cement?
Green concrete is the type of concrete which is much like the conventional concrete but the production of such concrete require minimum amount of energy and causes least harm to environment. It is a concept of using eco-friendly materials in concrete, to make the system more sustainable.
How is workability measured?
The slump test is the most well-known and widely used test for concrete workability since 1922. This is mostly due to its simplicity, low cost, and immediate results. Widely standardized on a global scale, the Slump Test is regulated by ASTM C143 in the United States and EN 12350-2 in Europe.
Who invented Portland cement?
Joseph Aspdin
What is the purpose of Portland cement?
Portland cement is the basic ingredient of concrete. Concrete is formed when portland cement creates a paste with water that binds with sand and rock to harden. Cement is manufactured through a closely controlled chemical combination of calcium, silicon, aluminum, iron and other ingredients.
What is concrete workability?
Concrete workability basically refers to how easily freshly mixed concrete can be placed, consolidated and finished with minimal loss of homogeneity. Generally the workability of concrete is determined by how fluid the mix is (i.e. the cement to water ratio).
What is the maximum limit ppm for chlorides in water?
250 ppm
Who is the father of cement?
William Aspdin
What is the hydration of cement?
What is Concrete Hydration? When cement, water, aggregate, and additives are mixed together, a significant heat increase occurs. This is due to the exothermic process in the reaction between cement and water (called hydration).
What is meant by food segregation?
Segregation rules are designed to minimise the risk of incompatible substances coming into contact with each other due to a leak, spill or vehicle accident and reacting dangerously. Segregation is also important to prevent food from becoming contaminated.
Why it is called Portland cement?
The inventor Joseph Aspdin, of England, patented the basic process in 1824, naming it for the resemblance of the cement when set to portland stone, a limestone from the Isle of Portland.
What is the percentage of iron oxide in white cement?
15 percent
What is the meaning of soundness of cement?
The soundness of cement refers to the stability of the volume change in the process of setting and hardening. If the volume change is unstable after setting and hardening, the concrete structures will crack, which can affect the quality of buildings or even cause serious accidents, known as poor dimensional stability.
What is workability Sanfoundry?
This set of Concrete Technology Multiple Choice Questions & Answers (MCQs) focuses on “Measurement of Workability”. 1. Explanation: Work ability of concrete is measured by slump cone test, compaction factor test. Slump cone is used for medium work ability. For high work abilities it is not accurate.
What is the standard slump for concrete?
Very dry mixes having slump 0 – 25 mm are typically used in constructing pavements or roads, low workability mixes having slump 10 – 40 mm are typically used for foundations with light reinforcement, medium workability mixes with slump 50 – 90 mm, are typically used for normal reinforced concrete placed with vibration.
What are the causes of segregation in concrete?
Segregation of concrete causes:
- Inappropriate mixing of concrete with greater water content.
- Poorly proportional mixing where sufficient matrix is not available for binding aggregates.
- Dropping concrete from a height as in concrete for columns.
- Badly designed mixer or worm-out blades.
- Excessive vibration of concrete.
Does segregation still exist?
De facto segregation, or segregation “in fact”, is that which exists without sanction of the law. De facto segregation continues today in areas such as residential segregation and school segregation because of both contemporary behavior and the historical legacy of de jure segregation.
Which equipment is used to test the workability?
Slump Testing Concrete slump test equipment is used to measure the consistency and workability of fresh concrete, and indirectly, the water/cement ratio of the concrete mix.
Why is concrete workability important?
Q. Why is the workability of concrete important? A. Any concrete mixture needs to be sufficiently workable to be properly placed and consolidated with the available procedures to fill the forms completely and surround the reinforcement and other embedded items.
What does segregation mean?
1 : the act or process of segregating : the state of being segregated. 2a : the separation or isolation of a race, class, or ethnic group by enforced or voluntary residence in a restricted area, by barriers to social intercourse, by separate educational facilities, or by other discriminatory means.
What is meant by segregation of concrete?
Segregation in concrete is a case of particle segregation in concrete applications, in which particulate solids tend to segregate by virtue of differences in the size, density, shape and other properties of particles of which they are composed.
Why clinker is used in cement?
Cement clinker is a solid material produced in the manufacture of Portland cement as an intermediary product. It is produced by sintering (fusing together without melting to the point of liquefaction) limestone and aluminosilicate materials such as clay during the cement kiln stage.
What is the most common cement?
Portland cement
What is Waste Management segregation?
Waste segregation is the separating and sorting of waste to facilitate recycling. For example, a company who sorts its cardboard packaging, glass containers, metal waste and wood waste will save a considerable amount of waste then sending a mixed material skip for recycling.
Who first invented cement?
Joseph Aspdin
What cures Sanfoundry?
This set of Concrete Technology Multiple Choice Questions & Answers (MCQs) focuses on “Curing of Fresh Concrete”. Explanation: Curing refers to hydration, the chemical process by which concrete hardens once it is poured.