adsense analytic

Showing posts with label Normal concrete. Show all posts
Showing posts with label Normal concrete. Show all posts

Friday, July 26, 2019

Properties and uses of white cement concrete

White cement concrete has similarity with grey Portland cement but the main difference lies in fineness and color. The white color of this cement is obtained by its manufacture system and its raw materials. There are wide array of color options in this type of cement for developing architectural and structural concrete.
This cement is formed with raw materials with little or no iron or manganese. Normally, china clay is utilized in white cement along with with limestone or chalk.
The cement should be white Portland cement with adherence to the standard specification ASTM C150.
The compressive strength of white cement is less as compared to OPC cement.
A large amount of iron and manganese are added in its manufacturing process to enhance the whiteness of the cement and becomes more expansive. White cement concrete is called as snow Crete. With white cement, a homogenous concrete is produced with exact color for a structure.
To develop white cement, 40% higher energy is necessary as compared to the normal grey cement and it makes the white cement expensive. Light colored sand along with whitest chalk is provided in the production of white cement.
HOW TO CHOOSE PROPER RAW INGREDIENTS:
Cement: The delivery of white cement in both bulks and bagged. The storage of the white cement bagged should not get in touch with the ground. If storing is made in the concrete floor then the cement should be stored up against the exterior walls. White cement bags should be preserved in pallets and it should be safeguarded from weather and maintain them off the ground. Due to the low content of soluble chromium, white cement should be preserved for minimum of 6 months when provided in proper dry condition.
Aggregates: The selection of aggregates for white should comprise of the white marble, white granite, and crushed calcinated flint. The color choice of coarse aggregates is crucial to the final appearance of white concrete. The selection of fine aggregates especially the filler particles should be lower than 0.25mm. Precautions should be taken to make sure that the mix of aggregates remain as constant as possible among batches to avoid in shading of finished products.
Water: Water to be mixed in white concrete should be clean and does not contain organic impurities. The water-cement ratio remains high in white concrete with regards to normal concrete and is critical in finding out the final strength of concrete.
CHARACTERISTICS OF WHITE CEMENT CONCRETE:
1. The initial setting time of white cement should 100 minutes.
2. The fineness of white cement should be 395 kg/m2.
3. The brightness of white cement should remain 87%.
4. The compact density of white density should be 3150 kg/m3.
5. Bulk density of white cement is 110 kg/3.
6. Compressive strength after 1 day 21 Mpa, after 2 days 38 Mpa, 7days 61 Mpa and after 28 days 74 Mpa.
APPLICATIONS OF WHITE CEMENT:
1. White cement is effective for decorative works as well as prestige construction projects.
2. White cement is applied to develop brightly colored concrete and mortars.
3. It is suitable for interior and exterior decoration due to its whiteness.
4. White cement is frequently applied in roads to enhance the visibleness to highway medians.
5. It is useful for huge numbers of manufacturing precast members.
Properties and uses of white cement concrete

~~~~~~~~~~~~~~~~~~~~~~~~
Published By
Rajib Dey
www.constructioncost.co
~~~~~~~~~~~~~~~~~~~~~~~~

Thursday, January 24, 2019

Details about High Performance Concrete (HPC)

Now-a-days, High Performance Concrete (HPC) is gaining popularity. HPC denotes superior concrete performance throughout wet stage (mixing & placing process); with greater strength in hardened stage together with a greater strength in long-run as compared to normal concrete.

The HPC is comprised of different chemical cum mineral admixtures and fibres. In HPC, the proportions are designed, or engineered, to create the strength and durability required for the structural and environmental requirements of the project.

High-strength concrete contains a specified compressive strength of 8000 psi (55 MPa) or higher. Special mixing, placing, and curing practices are required to develop and manipulate high-performance concrete. Normally, comprehensive performance tests are essential to show compliance with specific project requirements.

High-performance concrete is mainly utilized in tunnels, bridges, and tall buildings due to its strength, stability, and high modulus of elasticity. It is also been applied in shotcrete repair, poles, parking garages, and agricultural applications.

High-performance concrete characteristics are developed for particular applications and environments; some of the properties that may be required include:

• High strength
• High early strength
• High modulus of elasticity
• High abrasion resistance
• High strength and permanence in rigorous environments

• Low permeability and diffusion
• Defiance against chemical attack
• High resistance against frost and deicer scaling damage
• Toughness and impact resistance
• Volume stability
• Ease of placement
• Compaction devoid of segregation
• Inhibition of bacterial and mold growth


High-performance concretes are developed with cautiously chosen high-quality materials and optimized mixture designs; these are batched, mixed, placed, compacted and cured with reference to the superior industry standards.

Normally, such concretes will contain a low water-cementing materials ratio of 0.20 to 0.45. Plasticizers are normally utilized to produce these concretes fluid and workable. High-performance concrete almost always contains a greater strength as compared to normal concrete.

High-early-strength concrete, also known as fast-track concrete, attains its specified strength at an initial age as compared to normal concrete. The time period in which a specified strength should be attained may vary from a few hours (or even minutes) to several days. High-early-strength is achieved by employing conventional concrete ingredients and concreting practices, although sometimes special materials or techniques are necessary.

Details about High Performance Concrete

Read more
~~~~~~~~~~~~~~~~~~~~~~~~~
Published By
Rajib Dey
www.constructioncost.co
~~~~~~~~~~~~~~~~~~~~~~~~~