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What is the effect of age of concrete upon the water-cement ratio and strength curve?
The age of concrete significantly affects its water-cement ratio and strength. As concrete matures, its strength generally increases due to the ongoing hydration of cement particles, which leads to a denser microstructure. Initially, higher water-cement ratios may lower strength but are essential for workability; as concrete cures, the effective water-cement ratio decreases, contributing to strength gain over time. Ultimately, strength curves show that concrete continues to gain strength well beyond the initial setting period, often achieving substantial increases up to several months or years, depending on conditions.
What is size effect in concrete?
The size effect in concrete refers to the phenomenon where the strength and behavior of concrete structures vary with their size. Generally, larger concrete elements tend to exhibit lower strength and increased brittleness compared to smaller ones due to the statistical distribution of flaws and defects within the material. This effect is particularly significant in tension, where larger structures may fail at lower stress levels than smaller counterparts. Understanding the size effect is crucial for ensuring safety and reliability in the design of concrete structures.
Does gypsum improve strength if added to concrete?
Gypsum can improve the workability and setting properties of concrete, but it does not significantly enhance the overall strength of the concrete itself. Instead, gypsum is primarily used to control the setting time of cement and to prevent flash setting. While it helps in achieving a more uniform mix and can contribute to durability, the primary strength gains in concrete come from the hydration of cement and the aggregate properties. Therefore, while gypsum plays a supportive role, it is not a primary strength-enhancing additive.
Does the amount of water in a gravel based concrete depends on how fast it will harden?
yes, because after casting, concrete will get its 90% strength within 28 days and proper hydration require the proper amount of water for atleast 28 days.
What is tensile strength of concrete?
The tensile strength of concrete is 10% of it's compressive strength.
Meaning of hydration in concrete?
Hydration in concrete refers to the chemical reaction between water and cement which causes the mixture to harden and gain strength. This process is crucial for the development of the concrete's properties and durability. Proper hydration is necessary to ensure the concrete reaches its desired strength and durability.
What is hydration of concrete?
Hydration of concrete is a chemical reaction that occurs between cement and water, resulting in the formation of bonds between cement particles and aggregates. This process is essential for the concrete to harden and develop its strength and durability over time. Proper hydration is crucial for achieving desired concrete properties and ensuring long-term performance.
What are the problems associated with heat of hydration?
Some problems associated with heat of hydration include potential cracking and reduced strength of concrete due to rapid heat generation during the hydration process. Excessive heat can also lead to thermal gradients within the concrete, which can cause internal stresses and weaken the structure. Controlling the heat of hydration is important to ensure the durability and performance of the concrete.
What is the effect of age of concrete upon the water-cement ratio and strength curve?
The age of concrete significantly affects its water-cement ratio and strength. As concrete matures, its strength generally increases due to the ongoing hydration of cement particles, which leads to a denser microstructure. Initially, higher water-cement ratios may lower strength but are essential for workability; as concrete cures, the effective water-cement ratio decreases, contributing to strength gain over time. Ultimately, strength curves show that concrete continues to gain strength well beyond the initial setting period, often achieving substantial increases up to several months or years, depending on conditions.
What effect has the quantity of mixing water have upon the quality of concrete?
the strength of concrete is effected by water /cement ratio as the water/cement ratio increases the strength of the concrete decreases
Does concrete have crystals?
Yes, concrete does contain crystals. During the hydration process of cement in concrete, crystalline structures form as the cement particles react with water to create a solid matrix. These crystals contribute to the strength and durability of concrete.
How long does concrete need to cure in order to achieve maximum strength and durability?
Concrete typically needs to cure for at least 28 days to achieve maximum strength and durability. During this time, the concrete undergoes a chemical process called hydration, which strengthens the material and improves its durability.
What is curing of concrete?
The curing of concrete is a reaction between the type of cement in the concrete and the water. This reaction between cement and water is known as hydration. When the concrete sets and gains strength through this process it is known as curing. Test cylinders of concrete for construction projects are placed in a curing room where they are continuous misted with water at 23 +-2 degrees Celsius for 7 and 28 days before testing. This provides adequate curing.
What can effect the strength of concrete?
The water/concrete ratio, not mixing it well enough, quality of raw materials, the age of the concrete, and the temperature and humidity of the area surrounding the concrete.
What is the strength of steel reinforced concrete?
The reinforcment will have little or no effect on compressive strength. It will however impact tensile strength. It depends on the concrete mix design and amount of reinforcment, what the tensile strength impacts will be. The question needs to be a lot more detailed to provide a specific answer.
What does 28-days strength mean?
28-days strength refers to the compressive strength of concrete measured after 28 days of curing, which is a standard period for evaluating concrete's performance. This time frame allows the concrete to reach approximately 90% of its ultimate strength due to the hydration process of cement. It is a critical benchmark in construction, as it helps engineers and builders determine the suitability of concrete for various structural applications. Testing at this interval ensures consistency and reliability in structural integrity.
What is size effect in concrete?
The size effect in concrete refers to the phenomenon where the strength and behavior of concrete structures vary with their size. Generally, larger concrete elements tend to exhibit lower strength and increased brittleness compared to smaller ones due to the statistical distribution of flaws and defects within the material. This effect is particularly significant in tension, where larger structures may fail at lower stress levels than smaller counterparts. Understanding the size effect is crucial for ensuring safety and reliability in the design of concrete structures.
