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Building materials

The quality of the building materials lays the foundation for a successful SDA surface. Even before production, it must be ensured that aggregates, binders, and mastic meet the high requirements for durability, texture, and grip.

Aggregates

SDA mixtures are based on a load-bearing grain structure with a relatively high proportion of coarser particles. The following is crucial:

  • Mechanical strength and abrasion resistance of the grains (testing according to type H according to SN 670 103b)
  • Frost and polishing resistance to ensure long-term grip (recommended: PSV ≥ 52)
  • Cleanliness and petrographic quality – organic impurities or soft rocks reduce durability
Binders

For SDA surfaces, polymer-modified bitumen (PmB 45/80-65) is usually used. They offer:

  • High elasticity and temperature stability

  • Lower aging and crack susceptibility

  • Good adhesion between rock and binder

However, the quality of the binders can vary significantly within a type designation. Differences in polymer type, polymer content, or homogeneity of the mixture lead to differing behavior – especially at high temperatures or after aging.
Storage conditions, heating processes, and the mixing temperature in the asphalt plant can also significantly influence the properties of the binder. Too high temperatures or long residence times in storage lead to thermal damage and disentanglement of the polymers, which reduces elasticity and adhesion.

To ensure quality and reproducibility, best practice insights for asphalt plants and builders should be specifically promoted, for example through:

  • Standardized quality controls upon delivery and storage of polymer-modified binders (e.g., regular testing of penetration, softening point, elasticity)

  • Documented heating and mixing protocols for traceability of critical process parameters

  • Short training sessions and experience exchange between plant personnel, construction management, and testing laboratories on specific requirements for low-noise mixtures

  • Comparative measurements and round trials between asphalt plants to identify differences in material processing and their acoustic effects

  • Monitoring of selected reference routes to draw conclusions about the long-term effects of different bitumen batches or mixing processes

Such systematic knowledge transfer can help harmonize process stability and material quality across different production sites – a fundamental requirement for consistent acoustic and construction performance of SDA surfaces.

Mastic

The mastic provides the connection between rock and binder. The binder film thickness is described by the so-called Module de Richesse.
A value ≥ 3.8 is considered a guideline for a stable, durable mixture.
A film that is too thin promotes grain breakage, while one that is too thick can clog pores and reduce acoustic effectiveness.

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