“Blocker” Cement Grout System

Multigrout offers a technologically advanced “blocker” cement system which provides a simple, cost-effective solution to stop fluid inflow, a problem often encountered in underground works. The main benefit is the ability to precisely control the setting time.

The Blocker is described as a key component of the MultiGrout® injection grouting system – a complete suite of products for most injection grouting applications:

The Blocker cement system consists of two parts: the “Blocker” (Thermax™) and the “Timer” (C‑Max). The setting time is precisely controlled by varying the mix proportions, ensuring the grout reaches and stays in its intended location.

The Blocker cement system is stated to be suitable for mining and tunnelling applications including:

Thermax™ is described as a mixture of inorganic alkaline earth metal compounds and is stated to be environmentally safe. Main constituents are calcium and magnesium carbonate, magnesium oxide and magnesium sulphate.

C‑Max consists of magnesium chloride and must be dissolved in water prior to adding it to the mix.

Store under normal dry warehouse conditions. Protection from the atmosphere to prevent hydration is recommended. Stored properly, the shelf life is up to 24 months.

Mix proportions, temperature and time influence the setting process. The transition time from liquid to solid state is described as very short.

For rock injection grouting applications, a setting time of 10–90 minutes is stated as normal. Setting times from 15 seconds to 3 hours are also stated as achievable.

The low viscosity allows minimum pump pressures to be used throughout the process. The grout is stated not to pack or segregate in pressurised grouting lines.

The grout is stated to have a particle size distribution that allows injection into fine cracks and low-permeability formations.

The grout is described as having high strength suitable for applications involving high fluid pressures. A compressive strength at 24 hours of more than 20 MPa is stated as not uncommon.

The Blocker cement system is described as no more difficult to use than other cement products. Because it consists of more than one component, training is needed to achieve optimum results. Mix design varies by application and desired end result.

GroutAid® is stated to be routinely used to further improve stability and penetration characteristics and to provide additional flexibility in grout setting.

Contact your local MultiGrout® specialist representative for advice regarding your particular application.

The Blocker cement system, like any cementitious product, should be handled using appropriate precautions and safety equipment. Please consult the Material Safety Data Sheet.

The MultiGrout activities extend well beyond materials supply and are supported through a world-wide network of representatives. These activities involve a core group of technical specialists providing four key service elements:

The information given on this data sheet is based on many years of research and field experience and is accurate to the best knowledge of Multigrout personnel. However, due to the numerous factors that can affect the performance of injection grouts, with or without our products, Multigrout offers this information without guarantee and accepts no liability for any direct or indirect damages from its use.

If further information or assistance is required, please contact your local specialist representative or the office number given on this datasheet.