Bumper Plate – Solid Rubber BP "Anthracite"

The apparent density of a material describes the ratio of its mass to its total volume, including all pores, cavities, and air inclusions. For WARCO products, this value typically ranges between 600 and 1250 kg/m³. To clearly present the apparent density of a specific product, WARCO uses a scale from 1 to 5, with each scale value corresponding to a specific density range. For example, scale value 2 represents an apparent density between 780 and 840 kg/m³.

The physical density, also known as mass density, indicates the ratio of a substance’s mass to its pure material volume without considering cavities. It is expressed in units such as g/cm³ or kg/m³. For comparison: Water has a density of approximately 1 g/cm³ at 4 °C.

WARCO processes rubber granulate in its products, which is predominantly obtained from recycled used tyres. This so-called ELT granulate (End-of-Life Tyres) mainly consists of styrene-butadiene rubber (SBR) and natural rubber (NR) and has a physical density of around 1200 kg/m³. Some WARCO products also contain, or exclusively consist of, newly manufactured ethylene-propylene-diene rubber (EPDM), with a density of about 1600 kg/m³.

Since WARCO products are not made from solid rubber but from a mixture of rubber granulate and polyurethane binder, pressed into shaped elements with a defined proportion of pores and air inclusions, the specification of apparent density is crucial. It significantly influences the properties of the final product:

• Surface structure and resistance: Higher density leads to a firmer, smoother, and more resistant surface.

• Water permeability: Products with lower density are generally more water-permeable, making them particularly suitable for applications such as sports or impact protection flooring.

• Elasticity: Lower density results in softer and more elastic materials, while denser products are harder and more dimensionally stable.

By precisely adjusting the apparent density to the intended use, WARCO products can be optimally tailored to various requirements – from shock-absorbing impact protection mats to durable floor coverings for heavily used areas.

Rubber is an elastic material characterised by its ability to deform under tension or compression and then return to its original shape. This property makes rubber particularly effective for shock absorption, vibration reduction and impact sound insulation. In products made from polyurethane (PU) bonded rubber granules, the damping behaviour is further influenced by the elastic binder and the structure and density of the sheets.

A scale of 1 to 5 is used to rate the elastic, shock-absorbing and vibration-damping properties of a rubber product. A value of 1 represents slight but noticeable damping, while a value of 5 indicates exceptionally high damping performance. This classification is based on empirical studies and comparative measurements.

The elasticity of rubber and its importance

Rubber is made up of long, elastic molecular chains that temporarily adopt an ordered structure under mechanical stress. When the stress is removed, they return to their original disordered form, giving the material its high resilience. This elasticity enables efficient shock and vibration absorption.

Shock absorption - absorbing kinetic energy

Rubber can absorb kinetic energy through deformation and convert it into heat. On impact, the material deforms, reducing the forces acting on it. The damping effect is not linear, but increases with greater deformation. This means that rubber provides moderate damping at low loads, which increases significantly at high loads.

Vibration damping - reducing unwanted vibration

Rubber has viscoelastic properties, which means it has both elastic and viscous damping characteristics. Elastic damping occurs when vibrational energy is converted to heat by internal restoring forces, while viscous damping absorbs kinetic energy by internal friction. This makes rubber particularly effective in reducing vibration and shock.

Impact sound insulation - minimising footfall and impact sound

Impact sound insulation refers to measures taken to reduce the noise generated by walking or moving objects on a surface. Because of its elastic structure, rubber can effectively absorb and minimise these sounds. In addition, the material is wear resistant, ensuring that its sound-absorbing properties remain effective over a long period of time.

To determine the suitability of a WARCO product for a specific application, we recommend an individual assessment based on an on-site material sample.

The abrasion resistance of a floorcovering describes its ability to withstand material loss due to friction or wear. It is a key factor in determining the durability, functionality and quality of rubber granulate flooring.

A scale of 1 to 5 is used to classify abrasion resistance. A score of 1 indicates that the minimum requirements of BS 7188 are met, while a score of 5 indicates excellent abrasion resistance in accordance with this standard. The classification is based on test results obtained from representative products and then interpolated.

Abrasion resistance is determined using a standardised method in accordance with BS 7188. A sample of material is tested using the Taber Abraser, a device in which two standardised abrasive wheels apply a defined pressure and speed to the sample over a specified number of cycles.

To assess material wear, the sample is weighed before and after each test cycle. The difference between the initial weight and the weight after the test represents the incremental weight loss, which is used as a measure of wear.

In addition, the ageing of the material under atmospheric conditions and its behaviour under progressive abrasion are considered over several test cycles. From these tests, the wear index and wear ratio are calculated, giving an indication of the long-term durability and suitability of the floor covering.