Batimix Expansion M-820

Description

BATIMIX Expansion M-820 is a powder admixture designed to produce a slow and controlled expansion before the hardening of mortars and grouts. It does not contain chlorides or other ingredients that could potentially contribute to stress corrosion in steel.

Main Purpose

BATIMIX Expansion M-820 is used to prepare mortars, which develop controlled gaseous expansion that occurs before the initial set, forcing the mixture into close contact with surrounding surfaces. This product is used as a shrinkage-compensating material for plaster/render mortars applied on vertical, horizontal, or overhead surfaces. It can be incorporated in all types of mortars and grouts for masonry and repair, such as plastering, rendering, patching, and pointing.

Features

Mortars prepared with BATIMIX Expansion M-820 are characterized by the following:

In the plastic state:

• Slow and controlled expansion before initial set
• No detrimental effect on workability or setting

In the hardened state:

• Reduced crack occurrence due to plastic, drying, thermal, and autogenous types of shrinkage
• Increased joint spacing in pavements and walls
• Reduced water permeability and improved durability
• Longer mortar service life and better surface quality

Properties

• Appearance : grey powder
• Specific gravity : around 0.7 at 23 ºC
• Chloride content : nil
• Alkali content : typically less than 0.5% as Na₂O
• Air entrainment : typically less than 1% at normal dosages

Health and Safety

BATIMIX Expansion M-820 is not a hazardous material. However, it should not be swallowed or allowed to come into contact with skin and eyes. Suitable gloves and goggles should be worn. For additional information, kindly refer to the product’s Material Safety Data Sheet.

Dosage Rates

The recommended addition rate of BATIMIX Expansion M-820 may range from 0.05% to 0.5% of cement weight. Inside this range, the expansion varies almost linearly as a function of the dosage used. The optimum addition rate should best be determined by trials using the actual mix composition with site materials under conditions that will be experienced in field.

When designing mortar mixes with BATIMIX Expansion M-820, it is necessary to apply proper curing procedures to prevent fast water evaporation and thereby eliminate cracking.

For indication purposes, a volume increase in mortar prepared with 25% Portland cement, 75% sand, 0.50 W/C, and 0.2% BATIMIX Expansion M-820 can be around triple that obtained from a similar mortar made without such admixture. Test results were obtained after 28 days of air storage as per ASTM C 157.

EFFECT OF OVERDOSING

An overdose of BATIMIX Expansion M-820 will produce a significant increase in volume together with reduced compressive strength at all ages as compared to that normally obtained.

Compatibility

BATIMIX Expansion M-820 is compatible with all types of Portland cement, replacement materials such as silica fume, and other Holderchem admixtures incorporated in the same mortar. During batching, all admixtures should be added separately to the mortar mix. The performance of various admixtures on the fresh and hardened mortar properties should be assessed using trial tests.

Dispensing

BATIMIX Expansion M-820 should be added at the same time when introducing the dry cement, i.e. prior to incorporating all of the mixing water and other chemical admixtures.

Technical Support

Holderchem provides, upon request, technical advisory services pertaining to mix design, admixture selection, and materials evaluation.

Storage

BATIMIX Expansion M-820 has a minimum shelf life of 12 months if kept unopened and stored at temperatures ranging from 2 to 50 ºC.

Packages

• 1 t IBC
• 10 kg plastic bag
• 2 kg plastic bag