What Is Hardened Concrete | Properties of Hardened Concrete

Hardened Concrete

Hardened concrete is concrete that must be sufficiently strong to withstand the structural and service applied loads and it must be durable enough for the environmental risk for which it is designed. It is the strongest and durable construction material.

Hardened Concrete Definition

It is mainly the aggregate that provide strength to concrete especially coarse aggregates which act just like bones in the body.

What Makes Cement Harden?

Cement hardens when it comes into contact with water. This hardening is a process of crystallization. Concrete is completely fluid before the cement sets, then progressively hardens. The cement and water mixture that has crystallized in this way encloses the aggregate particles and produces a dense material.

What Causes Concrete to Harden?

The water causes the hardening of concrete through a process called hydration. Hydration is a chemical reaction in which the major compounds in cement form chemical bonds with water molecules and become hydrates or hydration products. … Aggregates are chemically inert, solid bodies held together by the cement.

Why Does Concrete Harden?

Cement hardens when it comes into contact with water. This hardening is a process of crystallization. Concrete is completely fluid before the cement sets, then progressively hardens. The cement and water mixture that has crystallized in this way encloses the aggregate particles and produces a dense material.

Why Does Concrete Get Harder Over Time?

Over time, those molecules react with carbon dioxide in the atmosphere to form calcium carbonate, which is referred to as carbonization. Calcium carbonate development further increases the compressive and flexural strength of the concrete.

How Do I Keep My Concrete from Hardening?

The ways to prevent evaporation are with curing blankets, plastic sheeting, or membrane-forming sprayed-on curing compounds. Curing compounds can be reasonably effective when evaporation is not too high. The better way to cure concrete, though, is with water curing.

How Does Concrete Harden?

The concrete solidifies and hardens through a chemical process called hydration. The water reacts with the cement, which bonds the other components together, creating a robust, stone-like material.

How Does Cement Harden?

Cement hardens when it comes into contact with water. This hardening is a process of crystallization. Concrete is completely fluid before the cement sets, then progressively hardens. The cement and water mixture that has crystallized in this way encloses the aggregate particles and produces a dense material.

Properties of Hardened Concrete

1. Strength: Hardened concrete has a number of properties, including Mechanical strength, in particular compressive strength. The strength of normal concrete varies between 25 and 40 MPa.
2. Impermeability: The impermeability of hardened concrete may be defined as the property to resist- entry of water. This property is achieved by using extra quantity of cement in concrete mix. A concrete in hardened state must be impermeable.
3. Durability: Concrete is extremely resistant to the physico-chemical attack emanating from the environment (frost, rain atmospheric pollution, etc.) It is particularly well-suited for structures exposed to demanding and extreme conditions.
4. Dimensional Changes: Concrete is not a completely elastic material or. completely plastic material. When the hardened concrete is loaded it undergoes deformation.
5. Shrinkage: The volume reduction that occurs primarily due to moisture loss after the concrete has hardened is known as drying shrinkage.

Mechanical Properties of Concrete

Performance of concrete is evaluated from mechanical properties which include shrinkage and creep, compressive strength, tensile strength, flexural strength, and modulus of elasticity.

Property of Concrete

1. Strength: Hardened concrete has a number of properties, including Mechanical strength, in particular compressive strength. The strength of normal concrete varies between 25 and 40 MPa.
2. Impermeability: The impermeability of hardened concrete may be defined as the property to resist- entry of water. This property is achieved by using an extra quantity of cement in concrete mix. A concrete in hardened state must be impermeable.
3. Durability: Concrete is extremely resistant to the physico-chemical attack emanating from the environment (frost, rain atmospheric pollution, etc.) It is particularly well-suited for structures exposed to demanding and extreme conditions.
4. Dimensional Changes: Concrete is not a completely elastic material or. completely plastic material. When the hardened concrete is loaded it undergoes deformation.
5. Shrinkage: The volume reduction that occurs primarily due to moisture loss after the concrete has hardened is known as drying shrinkage.

Tests on Hardened Concrete

• Compressive strength test (most common) – DT.
• Modulus of Elasticity – NDT.
• Split-tension test – DT.
• Flexural strength test – DT.
• Rebound hammer test – NDT.
• Penetration resistance test – NDT.
• Ultrasonic pulse velocity test – NDT.
• Maturity test – NDT.

Concrete Hardening

Cement hardens when it comes into contact with water. This hardening is a process of crystallization. Concrete is completely fluid before the cement sets, then progressively hardens. The cement and water mixture that has crystallized in this way encloses the aggregate particles and produces a dense material.

What Is Fresh and Hardened Concrete?

The purpose of slump test Is to determine the water content in concrete and its workability Consistency: Consistency or fluidity of concrete is an important component of workability and refers in a way to the wetness of the concrete.

How Is Concrete Hardened?

Cement hardens when it comes into contact with water. This hardening is a process of crystallization. Crystals form (after a certain length of time which is known as the initial set time) and interlock with each other. Concrete is completely fluid before the cement sets, then progressively hardens.

What Are the Different Properties of Fresh and Hardened Concrete?

Fresh concrete is arranged in a metal cone. When the cone is detached, the concrete slumps a specific amount on the basis of how fluid it is. A wet, soft mix slumps more as compared to a drier, stiffer one. A high-slump concrete is very fluid whereas a low-slump concrete is drier and more hard.

High-Strength Hardened Concrete Mix

High-strength hardened concrete mix is a type of concrete that is formulated to possess enhanced strength and durability compared to standard concrete mixes. It is typically used in construction projects where structural integrity and load-bearing capacity are crucial, such as high-rise buildings, bridges, dams, and other heavy-duty applications.

Durable Hardened Concrete Sealer

A durable hardened concrete sealer is a protective coating applied to cured concrete surfaces to enhance their durability, resist moisture penetration, and provide long-lasting protection against various forms of damage. It helps to extend the lifespan of the concrete, reduce maintenance needs, and enhance its appearance. Here are some common types of durable hardened concrete sealers:

Long-Lasting Hardened Concrete Additives

To enhance the longevity and performance of hardened concrete, various additives can be used during the mixing process. These additives can improve the concrete’s strength, durability, resistance to cracking, and other properties. Here are some examples of long-lasting hardened concrete additives:

• Fly Ash: Fly ash is a byproduct of coal combustion and is commonly used as a supplementary cementitious material in concrete. It improves the workability, durability, and long-term strength of concrete. Fly ash reduces the heat of hydration, lowers the permeability of concrete, and enhances resistance to sulfate and chloride ion penetration.
• Silica Fume: Silica fume is a byproduct of the production of silicon metal and ferrosilicon alloys. It is a fine, amorphous powder that is added to concrete to improve its strength, density, and durability. Silica fume fills the gaps between cement particles, making the concrete denser, more impermeable, and highly resistant to chemical attack.
• Slag: Ground granulated blast furnace slag (GGBFS) is a byproduct of the iron and steel industry. It can be used as a partial replacement for Portland cement in concrete. Slag enhances the long-term strength, durability, and resistance to chemical attack of concrete. It also reduces the heat of hydration and improves resistance to chloride ion penetration.

Crack-Resistant Hardened Concrete Techniques

To minimize the occurrence of cracks and improve the crack resistance of hardened concrete, several techniques can be employed during the design, placement, and curing processes. Here are some crack-resistant hardened concrete techniques:

• Proper Mix Design: A well-designed concrete mix is crucial for crack resistance. It should have a low water-cement ratio to reduce shrinkage and improve strength. The use of high-quality aggregates and supplementary cementitious materials like fly ash or silica fume can also enhance the mix’s durability and reduce the potential for cracking.
• Control Joints: Control joints are intentional grooves or weakened planes that are created in the concrete at predetermined locations. They help control where cracks occur by providing relief points for the concrete to shrink or expand without cracking randomly. Proper spacing and depth of control joints should be determined based on factors like slab thickness, concrete properties, and environmental conditions.
• Reinforcement: The inclusion of reinforcement, such as steel rebar or fiber reinforcement, helps distribute loads and resist cracking. Reinforcing bars provide tensile strength to counteract cracking due to shrinkage or thermal expansion. Fiber reinforcement, such as steel fibers or synthetic fibers, enhances the concrete’s ability to resist cracking and improve overall toughness.

Hardened Concrete Surface Repair Methods

There are several methods of concrete crack repair such as epoxy injection, routing and sealing, grouting, stitching, drilling and plugging, gravity filling of cracks in concrete.

Hardened Concrete Properties

Hardened concrete has a number of properties, including:

• Mechanical strength, in particular compressive strength. The strength of normal concrete varies between 25 and 40 MPa.
• Durability.
• Porosity and density.
• Fire resistance.
• Thermal and acoustic insulation properties.
• Impact resistance.

Property of Hardened Concrete

Hardened concrete has a number of properties, including: Mechanical strength, in particular compressive strength. The strength of normal concrete varies between 25 and 40 MPa.

What Is Hardened Concrete?

Hardened concrete refers to the state of concrete after it has undergone the curing process and has gained its desired strength and durability. When freshly mixed, concrete is in a plastic or fluid state, but as it cures, it undergoes a chemical reaction known as hydration. This reaction causes the cement particles to bind together, forming a solid mass.

What Do You Call the Process of Hardening of Concrete?

CURING. The second state of concrete is known as curing, which is what helps concrete develop its strength and durability. Curing takes place right after concrete has been placed and finished. During this process, moisture and temperature are controlled for an extended period of time.

How Hard Is Concrete?

Hardened concrete such as polished concrete is a relatively hard material, as its hardness varies between 6 and 7 Mohs.

Harden Concrete

Water facilitates the curing and hardening processes. Without it, the chemical reactions needed to form the hard crystals that give the concrete its strength can’t take place. Too little water leads to structurally weak concrete, and too much will disrupt effective curing and cause flaking, shrinking, divots or cracks.

Can Hardened Cement Be Reused?

While you won’t be able to use the hardened concrete for its original purpose, don’t fret. You can reuse and recycle the bags to make something new.

How to Remove Hardened Cement from Tiles?

Cover the cement stain with a towel that is soaked in vinegar and leave it there for around two-three hours. As the cement starts to loosen up, just use the scouring pad to scrub it off and remove the stains. Finally, just apply the dishwashing liquid to the scrubbed part and scrub thw tiles and floor using a sponge.