Experimental Investigation on Influence of Molding Methods on Properties of Pervious Concrete

Despite the common use of pervious concrete (PC), there is no standard way of producing the test specimens, which undergo testing to infer the behaviour of PC in the field. Vibrating table is the most common method but greatly reduced in vibration time compare with normal concrete in the laboratory. Marshall compaction and superpave gyratory compactor (SGC) are recommended standard molding methods for porous asphalt mixtures manufactured in the laboratory environment. Three kinds of pervious concrete samples with three target porosities were prepared by the above three methods, and the effects of the molding method on the physical properties, mechanical properties and durability of the samples were investigated in the study. Experimental results showed, with different molding methods adopting, pervious concrete with the same mixture design exhibits slightly different physical and mechanical properties. After analysis and comparison, SGC is the best choice to obtain concrete with high permeability, good freeze-thaw resistance and high strength, followed by Marshall compaction molding, and vibration molding is the last one. As a result, a win-win situation of the hydraulic characteristics and mechanical properties of pervious concrete can be achieved due to both optimized mix-design and appropriate molding method.

Investigation on Acoustic Versus Functional Characteristics of Porous Asphalt

The theoretical background, standards, and contract requirements of pavement friction courses involve functional (e.g., permeability) and acoustic (e.g., resistivity) characteristics. Unfortunately, their relationship is partly unknown and uncertain. This affects the comprehensiveness and soundness of the mix design of asphalt pavements. Based on the issues above, the goals of this study were confined into the following ones: 1) to investigate the relationship between acoustic and functional properties of porous asphalts; 2) to investigate, through one-layer (1L) and two-layer (2L) models, the effectiveness of the estimates of acoustic input data through mixture volumetric- and permeability-related characteristics. Volumetric and acoustic tests were performed and simulations were carried out. Equations and strategies to support a comprehensive approach were derived. Results demonstrate that even if the measured resistivity is very important, permeability-based estimates of resistivity well explain acoustic spectra. Furthermore, the distance between observed and estimated peaks of the absorption spectrum emerges as the best error function.

PERFORMANCE ANALYSIS OF PORUS ASPHALT MIXTURE USING ANTI-PELALING AGENTS WITH REAM SPECIFICATIONS

<p>Flexible pavement is very weak against waterlogging because water can loosen the bond between aggregate and asphalt. Porous Asphalt has lower durability because it has high pores so that it can be passed by water. Poor bonding of asphalt and aggregate will cause stripping. This peeling can cause water absorption which will eventually accelerate road damage. Derbo 401 anti-peeling material is one of the new breakthroughs, in the form of additives that can change the properties of aggregates and asphalt, increase adhesion and bonding, and reduce the negative effects caused by water so as to produce a mixture of asphalt with high adhesion. The purpose of this study was to determine the effect of adding anti-stripping agent type Derbo-401 to the permeability value and to determine the resistance of the porous asphalt mixture with the addition of anti-striping agent type Derbo-401 in the Cantabro test and to determine the microstructure of the porous asphalt mixture. Using the REAM-2008 Specification. Based on the results of the study, the Permeability Coefficient Value of the porous asphalt mixture was 0.254 cm3/sec. the lowest percentage Derbo 0.4%, the lowest Cantabro Loss value at 0.3% addition percentage gets an average value of 6.13%, Has met the required specifications max 15%. The elements that make up the porous asphalt mixture with the addition of Derbo percentage are more in the elements Si (silicon) 19.93%, Ca (calcium) 21.12%, S (sulfur) 8.45%, Fe (ferrum) 8.80%, K (potassium) 2.42% and the other elements are less.</p>

Application of Biochar on the runoff purification performance of porous asphalt pavement

Biochar is currently applied in many low-impact development measures, such as biofilters and filter strips. However, its application in permeable pavement is limited. Due to the wide range of raw material sources, biochar may also contain nutrients and heavy metals. Whether its leachate will cause contamination during application remains unknown. Based on the static leachate contamination test, this study first evaluated the leachate contamination risks of three types of biochar and porous asphalt mixture (PA) with three biochar fillers. Through the pavement infiltration test, the purification performance of PA with biochar fillers and filter layers was further analysed. The results show that biochar contains nitrogen and phosphorus, and the leaching contamination of coconut shell is the most obvious; when the biochar is applied as a filler in PA, the leaching contamination decreases, while the pollutant purification performance is not obvious; when 3−5 mm rice straw biochar is used as a filter layer, the removal rate of total suspended solids can be 100%, but it is accompanied by more serious nitrogen and phosphorus leaching, and the greater the thickness, the more serious the degree of leaching. Deionized water cleaning can remove the phosphates contained in biochar, but have little effect on nitrogen. Therefore, before the application of biochar, cleaning measures should be taken to minimize its leaching contamination.