Knowledge of the correlation between texture, skid resistance and influences on the noise emissions is the basic condition for the situational evaluation of the requirements of the road surface properties and the associated choice of the surface mixture goods (pavement choice).
By the quantified available findings of the correlations between texture, skid resistance and noise emissions of different road surface properties, basics are created, which make it possible in each individual case to specify the optimum of the three parameters appropriate for this case, but though no loss of road safety is to be feared.
Such basics represent important tools not only with new buildings but particularly for a lasting preservation of real assets of lanes with simultaneous and equivalent consideration of road safety and environmental compatibility.
This research does not evaluate the road surface condition. New bases for the standardisation of texture and conditions of skid resistance will be investigated within this study. Thus the project is capable of being differentiated from highway network wide assessment of the pavement conditions. It just uses the excellent data of this network wide condition survey to research the correlation between texture, skid resistance and influences on the noise emissions.
With the realisation of this research project the following three objectives are pursued:
- to identify quantified correlations between pavement texture and skid resistance of road surface of different pavement types
- to provide analysis of influences and effects of changes of texture (and skid resistance) on the noise emission
- to derivative of basic principles for the evaluation of texture as possible further condition characteristic to the total evaluation of road surface conditions.
The research methodology is divided into four phases, each of which forms a milestone with its financial statements and the achieved results:
Phase 1: Basic treatment
These aggregated in 100 m intervals from the network-wide state detection, unweighted survey results for the texture, feel, CPX noise emissions and flooring must be borne in preparation of reports in a database at the research centres. It concerns the following site-specific data for every 100 m interval respectively. Parts thereof:
- Texture: Medium texture depth MTD of macrotexture and texture spectrum
- Grip: friction SLK with associated measurement speed
- Noise Emission: CPX-value with associated measurement speed, city / highway
- Flooring: asphaltic concrete AC, stone mastic asphalt SMA, drain asphalt PA, mastic asphalt, Microrauasphalt MR, concrete
- Street Category: National Road Running forms 2 x 3, 2 x 2, 2, G
While the data texture, feel and noise emissions resulting directly due to the evaluations and aggregations of survey data, the data must be collected for the flooring updated ASTRA covering cadastre. The road categories should be moved from the RBBS-database.
Phase 2: analysis of data
The large data volumes are split noise emission in data subsets in a first step according to the criteria of road, lineage / ramps, measuring speed grip and measuring speed and designated accordingly. Another breakdown of flooring is done in parallel.
In the second step these data subsets are statistically processed so that each group distributions of values formed and the characteristic of the distributions sizes as averages, standard deviations, skewness, etc. are determined. They form the basis for the analysis of the data and the relationships.
Phase 3: Analysis of correlations
According to objectives of the research project is in principle the recognition of the following contexts in the foreground:
- Correlation between texture (macrotexture) and grip
- Correlation between texture spectrum and noise spectrum (on representative sections)
- Possible links between noise spectrum and grip.
Phase 4: conclusions and findings
In the final phase 4 the inferences to be closed and the knowledge gained collated. This is done through the creation of the final report. For the normalization, the research results are also set out in
In order to assess the quality of pavement surface characteristics for maintenance measures and type of surface layer it is necessary to recognize the correlations between texture, skid resistance of pavement surface and their impact on noise emissions.
International literature shows a variety of studies which describe findings regarding correlation between the pavement surface texture and skid resistance - often called "roughness" - of different types of pavement surface layers. Although the relationship between surface texture and skid resistance via influences from macro-textures and micro-textures have been known and described qualitatively, a quantitative determination is still not available.
This research project has focused on two main goals. The first goal was the analysis of correlation between texture and skid resistance to replace measurement of skid resistance by texture measurement. The second goal was to study the relationship between texture and tire-noise emission. This should enable to validate pavement surface layers regarding their tire-noise emission and durability.
The basis for this research is provided by the third pavement characteristics condition survey and assessment of Swiss national highway network from the Federal Roads Office (FEDRO) in 2009. This third survey included surface damage, longitudinal and transverse evenness, skid resistance as well as mean profile depths (macro-texture) and noise emission. The results consists of different aggregated datasets for each measured pavement surface characteristic in a separate raster of 100 m sections of all highways and highway ramps and access sections. Additionally, a dataset for all pavement layers including the age of the layer was provided by FEDRO. The survey was conducted with different measuring systems, such as ARAN for evenness and surface damage, SKM measuring system for skid resistance, laser profile-meter for macro-texture and CPX measurement system for noise emission.
A weak relationship between different pavement surface characteristics were expectable, due to the large and inhomogeneous dataset and various influences (e.g. age and type of surface layer, different relevance of sections, different climate condition subject to geographical regions in Switzerland, different weather condition during data survey). However, it is surprising that - after splitting the dataset into different types of pavement surface layers and grouping with respect to the age - no strong correlation within th
The here under the intended research project developed fundamentals provide important results is the assessment and choice of toppings for roads of national roads. This optimum sustainability is respect. Aimed at conservation activities. Security is ensured through sufficient grip and environmental friendliness over low noise tire / surface. The research provides an important contribution.
In addition to the specific intended use of the results at the national road of the Confederation, the results can be used also in high performance cantonal roads and main thoroughfares.
The beneficiaries are the one hand, the authorities you working for them engineering, which can take the bases for an optimal surface design in the concrete case. On the other hand, the road users usufructuary good grip properties and thus high traffic safety, but eventually benefit especially residents through lower dropout noise pollution.
Ultimately can be partial results for the standardization in the field of texture (VSS EK 7.11) used.