Batimix Blend Cement 720

Description

BATIMIX Blend Cement 720 is a ready-to-use binder composed of Type I Portland cement and silica fume. It is used to produce concrete with enhanced performance characteristics.

Main Purpose

Concrete made with BATIMIX Blend Cement 720 exhibits significantly improved particle packing as the ultra-fine particles of silica fume physically fill the voids in the cement paste. This yields a more densified concrete skeleton with reduced bleeding. On the other hand, silica fume reacts chemically with the calcium hydroxide present in the cement paste, yielding a calcium silicate hydrate gel that significantly enhances strength, water/chloride impermeability, and durability.

Applications using BATIMIX Blend Cement 720 include all types of high strength and specialty concrete mixtures such as underwater, shotcrete, self-consolidating, and pre-stressed.

Features

Silica fume is about one hundred times finer than Portland cement. It is twice lighter, which makes its storage and handling difficult at the job site. Concrete modified with fine raw material should be mixed longer to achieve homogenization with the cement. BATIMIX Blend Cement 720 facilitates the incorporation of silica fume in the concrete at the job site. Concrete prepared with this product is characterized by the following:

In the plastic state:

• Better cohesiveness with less bleeding and segregation
• Improved concrete pumping ability

In the hardened state:

• Increased compressive and flexural strengths at all ages

Properties

• Appearance: grey powder
• Specific gravity: 3.12

Health and Safety

BATIMIX Blend Cement 720 contains cement and silica fume. Avoid skin and eye contact to prevent irritation. Suitable gloves and goggles should be worn. For additional information, kindly refer to the product’s Material Safety Data Sheet.

Compliance with Standards

The Portland cement and silica fume contained in BATIMIX Blend Cement 720 comply with ASTM C 150 Type I and ASTM C 1240, respectively.

Dosage Rates

BATIMIX Blend Cement 720 is incorporated in concrete mixes at commonly used dosage rates that generally vary between 300 to 450 kg/m³, depending on the amount of strength increase and permeability reduction desired. Primarily trials tests are recommended using the actual mix composition with site materials.

Concrete containing BATIMIX Blend Cement 720 may be placed in the same manner as conventional concrete. However, special emphasis should be given to the finishing and curing operations. For example, silica fume makes the concrete more vulnerable to plastic shrinkage cracks due to the absence of bleeding associated with a rapid moisture loss from the concrete surface. In such a case, concrete should be promptly reworked and thoroughly covered with a wet burlap. On the other hand, proper curing methods such as continuous moist curing or liquid compound membranes should be implemented for a minimum of 7 days.

For indication purposes, the compressive strengths after 28 days of concrete made with 0.50 W/C and 350 kg/m3 of ordinary Portland cement or BATIMIX Blend Cement 720 will vary from 35.4 to 38.1 MPa, respectively.

Effect of Overdosing

An overdose of BATIMIX Blend Cement 720 will result in a significantly increased performance of concrete in terms of strength, permeability, and durability. However, particular care should be taken to secure adequate curing procedures right after placement to prevent all types of undesirable shrinkage such as plastic, drying, and autogenous.

Compatibility

BATIMIX Blend Cement 720 is compatible with all other Batimix admixtures incorporated in the same concrete. Cement replacement materials such as fly ash and blast furnace slag are also fully compatible with this product.

Dispensing

BATIMIX Blend Cement 720 is introduced in the concrete mixer in a manner similar to Portland cement or any other cementitious material such as fly ash or blast furnace slag. This product is generally used in conjunction with a high-range water reducer.

TECHNICAL SUPPORT

Holderchem offers technical consultancy services upon request, which are related to the design of concrete mixes, the selection of admixtures, the testing of materials, and the dispensing systems.

Storage

BATIMIX Blend Cement 720 has a minimum shelf life of 12 months if kept unopened and stored at temperatures ranging from 2 to 50 ºC.

Packages

• 1 t big bag
• 20 kg paper bag