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Polymer binders and silicone additives for cement

Cement is the most important binder of our time and the basis of concrete – the most widely used construction material. While cement makes durable and versatile applications possible, the inorganic binder is very sensitive to moisture during storage and to processing in concrete and dry mixes. Cementitious formulations, too, offer potential for optimization in terms of durability and mechanical performance such as flexibility and adhesion. Exposure to moisture often leads to undesirable aging such as hydration and clumping, which in turn impairs quality.

WACKER’s product portfolio greatly enhances the performance of cement and cement-bound building materials. In addition to excellent compatibility with cementitious systems, our products can optimize the mechanical properties and storage stability of cement and the water repellency of construction materials.

Cement – challenges and solutions

Typical challenges:

  • Moisture can lead to hydration and clumping in cement and cementitious building materials, which is associated with a loss of quality
  • Insufficient adhesion and low flexibility reduce the durability of mortar and concrete systems
  • Capillary water absorption promotes efflorescence, corrosion and damage to concrete and reinforcement
  • High demands on ease of processing, storage stability and mechanical properties complicate the formulation of modern building materials

Our solutions:

VINNAPAS® and ETONIS® polymeric binders enhance the performance of cementitious formulations in concrete and in applications relating to dry mixes, such as mortar. Polymer additives increase adhesion, cohesion, flexibility and flexural strength and make durable, high-performance construction-material systems possible.

SILRES® BS silicone additives reliably stabilize cement against moisture, reduce prehydration and prevent clumping during storage and shipment. At the same time, these silicone additives transfer their hydrophobic properties to mortar and concrete and permanently reduce capillary water absorption.

Product properties

Dispersible polymer powders and polymer dispersions enable the modification of cementitious formulations.

Benefits:

  • Excellent compatibility with cementitious systems
  • Improved flexural strength and reduced modulus of elasticity (e-modulus)
  • Excellent workability with long pot life
  • Increased adhesion, cohesion and durability on a very wide range of substrates

Applications:

  • Mortar and concrete modification as a dry mix using dispersible polymer powders (1K) or polymer dispersions (2K) on the construction site
  • Polymer binders as an additive to increase adhesion, cohesion and durability on critical substrates or to meet ever greater performance requirements
A bar chart shows how the addition of the SILRES® BS 8010 silicone additive reduces cement clumping. The y-axis shows the force required to break a clump, in kilonewtons. The bars illustrate that cement samples with added SILRES® BS 8010 require significantly less force than the reference samples. A dashed line marks the transition from ‘soft’ to ‘hard’.

High-performance organosilicon admixtures are introduced during cement production. Providing effective protection against ambient moisture, these admixtures consequently reduce the risk of prehydration.

The bar chart shows how the addition of SILRES® BS 8010 to cement reduces the absorption of ambient moisture and reduces clumping.

Line chart showing the capillary water absorption of three mortar samples. The y-axis shows capillary water absorption in milligrams per square millimeter, and the x-axis shows the number of days. The graph shows three curves for mortar samples in accordance with EN 480-5: The reference sample exhibits the highest capillary water absorption, followed by the sample modified with 250 ppm SILRES® BS 8010. The sample with 500 ppm SILRES® BS 8010 exhibits the lowest water absorption. The values increase for all samples in the first few days and then stabilize.

The water repellency of the cement treated with SILRES® BS 8010 is transferred to its mortar and concrete products: capillary water absorption decreases.

Product properties

Silicone additives for mixing with cement and cement-based construction materials

Benefits:

  • Excellent compatibility with cement
  • Stabilization against premature hydration during storage (especially in bags)
  • Prevention of cement clumping (e.g. in silos)
  • Cost savings gained by additional reduction in grinding energy and increase in mill throughput
  • Transferring water repellency from the cement to its mortar and concrete products
  • Moisture penetration is prevented, the formation of efflorescence is suppressed and the reinforcing steel is protected against corrosion
  • The properties of fresh and hardened concrete are virtually unaffected

Applications:

  • Cement treatment
  • Cement stabilization

FAQs on cement

SILRES® BS silicone additives protect cement against moisture and prevent prehydration and clumping. As a result, the cement remains stable for longer during storage and its quality remains constant. In addition, the hydrophobic properties are transferred to the resultant construction material, such as mortar and concrete. This prevents the penetration of moisture, suppresses the formation of efflorescence and protects the reinforcing steel against corrosion.

VINNAPAS® and ETONIS® polymer-based binders increase the adhesion, flexibility and flexural strength of cementitious mortars and make crack-free, durable results possible – even when used on a wide variety of substrates.

VINNAPAS® and ETONIS® binders and SILRES® BS silicone additives enhance the efficiency and durability of cementitious systems. The consumption of less material and energy, combined with a longer service life, promotes sustainable construction.