PURPOSES : The objective of this study was to evaluate the effectiveness of dust removal by dust removal vehicles by the measuring dust load and PM10 concentrations on the sidewalks of block pavements. METHODS : Field experiments were conducted to determine a dust removal method suitable for the sidewalk conditions, as identified through a literature review. Data collection was followed by the evaluation of the sidewalk dust load with removal vehicles and analysis of the PM10 content within a service road. Moreover, an economic analysis was conducted based on the social costs of dust reduction. RESULTS : When cleaning a sidewalk block by spraying water, the contaminants in small gaps in the block pavement could be reduced, providing a potential solution to void clogging. The dust on the surface of the sidewalk was suspended from a paved road with a high level of traffic volume. Using sidewalk dust removal vehicles with sweeping, spraying water, and inhalation reduced the dust load and PM10 contents by more than 2 and 0.07g/m2, respectively. CONCLUSIONS : According to the economic analysis of the development of dust removal vehicles for sidewalks, the cost-benefit analysis method shows an input effect of 0.4, but if the reduction amount of fine particles such as PM2.5, further experiments are necessary to address the atmospheric fine dust concentrations resulting from cleaning sidewalk block pavements.

PURPOSES : Abroad, road pavement materials vary depending on the speed and traffic volume of vehicles, but owing to the negative perception of block pavements, sidewalks, parking lots, and parks are primarily used in Korea. In addition, since speed restriction policies such as safety speed 5030 have been implemented recently, it is necessary to use block pavements for roadways, which are considered to have the effect of reducing speed. Therefore, it is necessary not only to actively discuss the introduction of block pavements for roadways but to continue research on the effectiveness of the performance evaluation and to change the perception of roads in Korea. METHODS : In this study, five indicators (surface damage, surface temperature, driving speed of vehicle, noise, and suspended dust) were selected for a sustainable road environment. The performance evaluation index of block pavement for roadways was decided according to the domestic and international literature, and the data were collected based on the evaluation index in the section with block pavement for roadways in Korea. RESULTS : The damage rate was calculated 0.35% according to the breakage of block and Maintenance Control Index(MCI) was ranked A~B even though the pavement was used for more than 4~5 years. The surface temperature of block pavement has a temperature reduction effect of 7 ℃ compared with ordinary asphalt pavement and a speed reduction of approximately 4 km/h on average; therefore, the traffic calming effect of block pavements can be expected. The noise of block pavement and asphalt pavement exhibited a similar level, and the noise level experienced by pedestrians did not change significantly as a result of frequency analysis. The measurement of road suspended dust around the road confirmed the possibility of reducing the concentration of road dust in the air owing to the smooth surface drainage and the results indicated the possibility. CONCLUSIONS : The results of this study are expected to contribute to the recognition and functional improvement of domestic block pavements by continuous monitoring to ensure the reliability of blocks. In addition, it is necessary to ensure the reliability of the quality and functional evaluation of paving materials through continuous on-site monitoring.

PURPOSES : The purpose of this study is to develop a solar powered block pavement system satisfying the road design criteria in Korea. The concrete block pavement system was chosen as the most suitable for development at the current level of technology. METHODS : A new solar block pavement system was conducted by seperating the solar module from the concrete block. The solar panel module is responsible for the solar powered system and the solar concrete block is responsible for the vehicle load support. Quality criteria for block pavements in Korea were collected to select the appropriate quality criteria for a solar block pavement system. The laboratory tests conducted were slip resistance test, compressive strength test and absorption rate test of the concrete blocks, flexural strength test of the acrylic protection panel, and UTM load test of the solar panel module. Solar power measurement was also conducted at the field test section for field performance evaluation. RESULTS : The acrylic protection panels were selected as 15mm thick panels with diagonal patterns of 45°, considering the power generation efficiency, appropriate thickness of the solar power modules, slip resistance and flexural strength. The results of the laboratory tests for evaluating the structural performance of concrete blocks demonstrated that the compressive strength and absorption rate were 22.7 MPa and 3.4% on average, respectively. From these results, it can be observed that the concrete blocks of the solar block pavement system satisfy the block pavement criteria in Korea. As a result of the UTM load test of the solar panel module, the maximum compressive load was found to be 26 tonf on average, and it was confirmed that damage does not occur under a passenger car load. CONCLUSIONS : A new solar block pavement system was developed by seperating the solar module and concrete block. As a results of the laboratory and field tests, both the solar module and concrete block satisfied the quality criteria for block pavement in Korea.

PURPOSES : In this study, a numerical clogging model that can be used to realistically visualize the movement of particles in cylindrical permeability test equipment was proposed based on the system coupling of computational fluid dynamics with the discrete element method and experimental permeability test results. This model can also be used to simulate the interaction of dust particles with bedding particles. METHODS: A 4-way system coupling method with multiphase volumes of the fluid model and porous media model was proposed. The proposed model needs to consider the influence of flow on the dust particles, interaction between the dust particles, and interaction between the dust particles and bedding layer particles. The permeability coefficient of the bedding layer in cylindrical permeability test equipment was not calculated by using the permeability test result, but was estimated by using the particle packing model and Ergun model. RESULTS : The numerical simulation demonstrated a good agreement with the experimental test results in terms of permeability and drain time. Additionally, the initial movement of particles due to the sudden drain hole opening was successfully captured by the numerical model. CONCLUSIONS : A 4-way coupling model was sufficient to simulate the water flow and particle movement in cylindrical permeability test equipment. However, additional tests and simulation are required to utilize the model for more realistic block pavement systems.

PURPOSES : In this study, a series of fundamental falling head permeability tests were conducted on a binary particle mix bedding to determine the minimum water level, bedding layer thickness, and amount of dust that can result in the stable permeability with high repeatability. The determined condition is used to develop a CFD-DEM coupled clogging model that can explain the movement of dust particles in flowing water of a block pavement system. METHODS: A binary particle mixture is utilized to experimentally simulate an ideal bedding layer of a block pavement system. To obtain a bedding layer with maximum packing degree, the well-known particle packing degree model, i.e., the modified Toufar model, was utilized. The permeability of the bedding layer for various water levels, bedding layer thicknesses, and amounts of dust was calculated. The permeability for a small water level drop was also plotted to evaluate the effect of dust on the bedding layer clogging. RESULTS: It was observed that a water level of 100 mm, bedding depth of 70 mm, and dust amount of 0.3 g result in a stable permeability condition with high repeatability. The relationship between the minimum dust amount and surface clogging of the bedding layer was suggested based on the evaluation of the volumetric calculation of the particle and void and the permeability change in the test. CONCLUSIONS: The test procedure to determine the minimum water level, bedding thickness, and dust amount was successfully proposed. The mechanism of clogging on the surface of the bedding layer was examined by relating the volumetric characteristics of dust to the clogging surface.

PURPOSES : The purpose of this study is to evaluate the performance of road stone block pavements using APT (Accelerated Pavement Testing), which can evaluate the short-term pavement performance of a pavement structure for a given traffic load. METHODS : The performance of stone block, concrete block, and asphalt (modified SMA) pavements were evaluated according to the cumulative equivalent load by using APT. The FWD (Falling Weight Deflectometer) test was used to analyze the deflection per unit load. In addition, the plastic settlement was analyzed by transverse profile measurement. RESULTS: The results of the APT of about 197,000 ESALs (Equivalent Single Axle Loads) show that there were no damages in the stone block, concrete block, and asphalt pavement, such as breakage of stone or concrete block, cracking of asphalt, deflection, and plastic settlement of the wheel-pass section. It was analyzed that the bearing capacity of each pavement section did not decrease sharply with increase in cumulative ESAL. The results of plastic settlement analysis show that in the case of asphalt pavement, the plastic settlement steadily progressed from the beginning of the APT, and a settlement of about 4.76 mm occurred. In the case of concrete block and stone block pavements, no significant change occurred after the initial stabilization step, and plastic settlement of about 1.01 mm and 0.17 mm occurred for the concrete block and stone block pavements, respectively. CONCLUSIONS : As a result of the analysis of the bearing capacity and plastic settlement after the APT, the performance of stone pavement was found to be similar to that of asphalt pavement and concrete block pavement. Therefore, it is concluded that stone pavements are applicable for the road pavement system.

PURPOSES: This study aims to evaluate the performance of interlocking block pavement system for low speed highway. METHODS: Through on-site monitoring, environmental impact assessment of interlocking block pavement such as heat island reduction, traffic safety, noise pollution were evaluated as compared with asphalt pavement. Also the pavement condition and roughness were evaluated according to performance period. RESULTS: Surface temperature of interlocking block pavement was about 7 degree lower than asphalt pavement in midsummer. Compared to asphalt pavement, vehicle speed reduction effect of interlocking block pavement was about 2kph. For low speed driving, the noise pollution was measured at a similar level for both asphalt and interlocking block pavement. After 42month service period, the breakage of block was only 0.24% for the whole surveyed area. IRI of interlock block pavement was estimated within the range of 5~8m/km. CONCLUSIONS : Depending on the performance monitoring results such as heat island reduction, providing traffic safety and keeping a good pavement condition for a long service period, it assures that interlocking block pavement was applicable for low speed road.