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Although the splash and spray phenomenon produced by heavy trucks on road pavements is not a significant issue in relation to traffic safety, it may cause considerable inconveniences for those driving cars or motorbikes. This paper addresses the issue of pavement engineering with regard to surface characteristics; particularly pavement texture and its influence on water mobilization and projection in conditions of wet weather and heavy traffic. Considering the theoretical concept of pavement macrotexture, the analysis starts with the hypothesis concerning a relationship between Mean Profile Depth (MPD) and water splashed during rain. In order to focus on the impact of texture on splash and spray, a field experiment was carried out to test the hypothesis using 5 test tracks on a range of different pavement textures. The experiment was performed using a Traffic Speed Drain Meter (TSDM), which is a new drainability survey device presented to PIARC for approval. This equipment employs the laser and image technology and allows one to simultaneously obtain MPD and water splash data. The results of drainability and MPD were compared for each test track. Having analysed the pavements with different MPD ranges in the experiment, it has been concluded that MPD and water splashed apparently have an inversely proportional relationship. In addition, the TSDM proved to be a suitable equipment (repeatability) at an affordable cost (high performance of data collection). Finally, it has been concluded that there is a way to reduce splash and spray adjusting the infrastructure rather trying to solve the issue modifying vehicle moving modes. Therefore, if the issue is properly addressed by civil engineers and road managers, road safety in the areas of heavy rain may be improved at an affordable cost. The experiment presented here is considered a starting point opening the path for further research.

Pervious concrete provides a sound solution for managing storm waters in built environments where the water runoff as well as the natural recharge of the groundwater are important issues. The use of pervious concrete is also commonly related to other environmental benefits such as the Urban Heat Island reduction, traffic noise absorption, and pollutant filtering. Despite the broad capabilities, comprehensive standards are still limited and many issues have not yet been completely fixed. For example, compaction is often underestimated and one of the common compaction effort is provided by hand-rolling; however, different compaction energies, techniques, or timing can significantly affect mechanical and functional properties of the material. Performance can be furthermore improved by adding a small amount of fine sand, as suggested by many; sand can lead towards better raveling and skid resistance, also improving the maximum flexural strength. On the other hand, too much sand and improper compaction energy may lead to an excessively low void content and reduced drainability features. Compaction and sand addition should be therefore analyzed more in details. The present research aimed at (1) evaluating the effect of differential levels of compaction energy and (2) analyzing the influence of fine sand addition into several pervious concrete mixtures. Results suggested that adding small amounts of fine sand (around 5% of the total aggregate weight) to pervious concrete mixtures provided better mechanical and surface properties, and a consequent reduction of drainability. However, the correct balance of mechanical and hydrological properties can be achieved due to both accurate mix-design and proper compaction plan.

Maintenance and reconstruction of road pavements involve the production of huge amount of discarded material, such as reclaimed asphalt (RA), every year. As a consequence, issues related to RA stockpiles and disposals are dramatically increasing. At the same time, the growing importance of environmental and economic matters has led researchers and engineers to promote reusing milled materials rather than using valuable and nonrenewable natural resources (bitumen and aggregates). Road pavement maintenance and construction usually involve the use of porous asphalt (PA) mixtures, in particular in the case of motorways and highways. In fact, PA mixtures are widely employed as pavement surface layer thanks to their ability in reducing traffic noise and enhancing safety in wet conditions. In this sense, the reuse of RA into PA should be strongly encouraged. Unfortunately, technical specifications adopted in many countries do not allow any recycled materials in porous asphalt surface layers yet. Thus, re...

The objectives of the four-year quieter concrete pavement research study presented in this report were to measure noise from tire/pavement interaction, pavement smoothness, and drainability characteristics of concrete pavement surface textures currently used on the California state highway network. This study also was undertaken to develop recommendations for safe, durable, and cost-effective concrete pavement surface textures that minimize noise from tire/pavement interaction. The fourth and final year of this research study included testing on 60 test sections grouped by texture type as follows: 27 diamond ground (DG), 12 diamond grooved (Gr), 19 longitudinally tined (LT), 1 burlap drag (BD), and 1 longitudinally broomed (LB). Five of the 60 test sections were continuously reinforced concrete pavement (CRCP) and the rest were jointed plain concrete pavement (JPCP). This report presents the results of measurements of tire/pavement interaction noise and of the pavement smoothness and surface drainability characteristics of concrete pavement textures commonly used for new construction finishes or pavement preservation and rehabilitation strategies. Tire/pavement interaction noise was measured using the on-board sound intensity (OBSI) method; smoothness was measured in terms of the International Roughness Index (IRI) using a wide-spot (RoLineTM) laser; pavement surface drainability was measured using outflow meter measurements as well as in terms of Mean Profile Depth (MPD) and Mean Texture Depth (MTD). The results indicate that the OBSI levels for the concrete pavement sections evaluated in this study ranged from 100 dBA to 112 dBA, which is the same as the range of OBSI levels for concrete pavement textures measured in other similar studies. The average OBSI levels for the three commonly used texture types in California (DG, Gr, and LT) where the textures were not worn out ranged from 104 to 107 dBA, with DG and Gr sections typically being quieter than LT sections of similar age and texture condition. For comparison, the OBSI levels for the experimental grind-and-groove sections averaged 101 dBA. The average IRI values for the DG, Gr, and LT sections across all three texture conditions (new, aged, or worn out) were 68, 81, and 96 inches/mile, respectively. The results for the outflow meter times and the MPD values indicate that diamond-grooved sections had a greater capacity for allowing water to move out from under the tire. This suggests that diamond-grooved concrete pavements would generally be more effective in reducing the risk of hydroplaning than diamond-ground or longitudinally tined concrete pavements.

This research report presents the results of tire/pavement noise, friction, drainability, and profile measurements performed on conventional diamond grind (CDG) and grind and groove (GnG) concrete pavement surface textures as a part of the California Department of Transportation (Caltrans) Quieter Pavement Research (QPR) study to investigate tire/pavement noise on concrete pavements. The On-board Sound Intensity (OBSI) method (AASHTO TP 76) was used to measure tire/pavement noise. Longitudinal profile data were collected at the same time as the OBSI data using an inertial profiler (ASTM E950) and were used to calculate the International Roughness Index (IRI). Friction was measured using the Towed Skid Trailer (ASTM E274) and the California Portable Skid Tester (CT 342), and estimated using the Circular Track Meter (ASTM E2157) and Dynamic Friction Tester (ASTM E1911). Drainability was measured using the Outflow Meter (ASTM E2380). Seven pilot projects scheduled for CDG were selected for this research study. They include one each in San Diego, San Joaquin, and Yolo counties, and four in Sacramento County. At these seven sites, measurements were made before and after construction, and in between construction phases when possible. The GnG surface texture was found to be quieter than the CDG, with lane average OBSI values on the GnG texture ranging from 99.5 dBA to 101.7 dBA, with an average of 100.8 dBA, compared with a range of 100.6 dBA to 104.7 dBA, and an average of 102.8 dBA measured on the CDG surface texture. The average OBSI level for all GnG sections was 100.8 dBA compared with an average of 102.8 for all CDG sections. OBSI values on the CDG texture on the San Diego 5 project decreased by 0.5 dBA over 1.3 years where OBSI was measured several times after initial construction. This reduction was attributed to flattening of the “fins” produced by CDG during construction. The average OBSI for all sections prior to treatment was 104.4 dBA, although not all sections had measurements of both CDG and GnG. The IRI measurements showed that both CDG and GnG texturing treatments improved smoothness substantially compared with the pretreatment values. The average IRI was reduced from 142 in./mi for the preconstruction surface textures to 64 in./mi on average after the CDG treatment and to 49 in./mi on average after the GnG texture treatment. Both the OBSI and IRI are improved by CDG and even more so by the GnG texturing. Both CDG and GnG remove sealant overbanding and reduce or eliminate faulting at joints and cracks. Both processes also remove imperfections in the slabs caused by curling, warping, and most of whatever roughness was introduced during initial construction. All of these changes that result from CDG and GnG are likely to contribute to reductions in both noise and roughness. In this study, however, the individual contributions of removal of faulting and overbanding to noise and roughness reductions were not measured. The few friction measurements on the GnG texture using CT 342 were not sufficient to draw conclusions, indicating that further attention should be given to use of this test on this texture if Caltrans continues to use the test. The skid tests using ASTM E 274 indicated that both the CDG and GnG textures passed specifications used by most state highway departments.

The pulp and paper industry has started applying new, ecologically sound technology (biotechnology) in its manufacturing processes. Many interesting enzymatic applications have been proposed. Implemented technologies tend to change the existing industrial process as little as possible. Enzymes have great potentials in solving many problems associated with the use of recycled fiber, especially related to deinking, drainability, hornification, refining, and stickies. Based on the promising results of mill-scale trials, several mills in the world have started using enzymes for deinking. The potentials of cellulase enzymes have also been demonstrated for reducing the energy requirement in pulp refining, improving the machine runnability and stickies control when using recycled fiber. They have the important benefits in that they can be considered a “green” product. They are natural occurring compounds with little adverse impact on the environment. This paper deals with the importance of recycling of paper, problems associated with the recycling, and potentials of enzymes in solving these problems. A few case studies have also been included.