Sand Patch Test Research Articles

Micro Surfacing Asphalt Pavement as a Mitigation Measure at Accident’s Prone Area along East Coast Expressway Phase 2 (ECE 2)


 
 
 The condition of pavement surface is an essential factor to be considered in mitigation of accidents in highways, as it is in direct contact with users' vehicles, especially in terms of quality of driving, skid resistance and friction. Lack of surface pavement maintenance may lead to accidents, and if taken for granted, it may witness high accident fatalities in the expressways. If the cause of the accidents happening on the roads is due to engineering factors, then adequate mitigation measures should be undertaken to avoid further tragedies from happening. One way of mitigating the accidents on highways is by conducting periodic maintenance of the roads and related highway infrastructure. Micro- surfacing is one of the potential measures, developed from a slurry seal technique. It is the process of applying a mixture of polymer modified bitumen emulsion with 8.0 mm chipping, quarry dust, cement, additives and water on an existing asphalt pavement surface. The current study was carried out to evaluate the performance of micro-surfacing as a mitigation measure, applied on the accident-prone pavement areas along the East Coast Expressway Phase 2 (ECE2). The Portable Pendulum Tester was used to evaluate the skid resistance performance while the texture depth of micro-surfacing was measured using the Sand Patch Test. The results showed tremendous improvement in the skid resistance and texture depth after the application of micro-surfacing. The number of accidents also reduced after the application of micro-surfacing asphalt pavement as a mitigation measure at the identified accident-prone areas along ECE2. Thus, the study confirmed that micro-surfacing asphalt pavement was effective in mitigating the accidents in accident-prone areas along ECE2.
 
 

Research Progress on Skid Resistance of Basic Oxygen Furnace (BOF) Slag Asphalt Mixtures.

In order to ensure the safety of traffic, asphalt pavement is commonly required to utilize aggregates with excellent anti-abrasion property. This results in the lack of high-quality aggregates. The incorporation of solid waste in the aggregates is regarded as a high potential alternative for solving this problem. Since its material properties, such as rough surface, high Polished Stone Value (PSV) and the excellent adhesion property of asphalt, Basic Oxygen Furnace (BOF) slag can effectively improve the skid resistance of asphalt mixtures. First, the material properties of BOF slag are reviewed in this study. Then, the skid resistance of asphalt mixtures and aggregates are commendably evaluated by the Polished Stone Value test, Wehner/Schulze Tester, Aachen Polishing Machine, British Pendulum Test and Sand Patch test. The physical and mechanical properties of BOF slag play a key role in asphalt mixtures. This review found that the skid resistance mechanism of the BOF slag asphalt mixture is governed by factors such as BOF slag properties, incorporation methods and gradation types. Finally, the economic and environmental benefits of BOF slag asphalt mixtures were discussed. In addition, the function of gas catalysis and the melting of ice and snow can be added to the BOF slag asphalt mixture for a cleaner development in engineering. Furthermore, the existing problems, research directions and corresponding measures in this field are directed towards more durable and functional asphalt pavement construction.

Effect of nominal maximum aggregate size and aggregate gradation on the surface frictional properties of hot mix asphalt mixtures

Roadway friction is one of the most important features for road safety. Many procedures, tests, and tools have been used widely to measure surface frictional properties of flexible pavements. The main objective of this study is to evaluate the surface characteristics of Superpave laboratory-prepared Hot Mix Asphalt (HMA) specimens made of local resources and to study the role of the Superpave Gyratory Compactor (SGC) in fabricating the top and bottom surfaces of HMA specimens. The evaluation was carried out using two methods; the British Pendulum Test (BPT) and the Sand Patch Test (SPT). Asphalt mixtures were prepared using PG 70–10 asphalt binder and crushed limestone aggregate with three Nominal Maximum Aggregate Sizes (NMAS); 19 mm, 12.5 mm, 9.5 mm and involving two types of gradations for each NMAS; Fine Gradation (FG) and Coarse Gradation (CG). Analysis was performed using descriptive charts and analytical techniques including the three-way Analysis of Variance (ANOVA) and regression analysis. The study has shown that the surface frictional properties of mixtures’ top surfaces were significantly affected by the NMAS and aggregate gradation type. Accordingly, by increasing the NMAS in the mix, the top surface exhibits improved macrotextures and lessened microtextures for both types of aggregate gradations. On the other hand, the frictional properties of the bottom surfaces were only affected by the aggregate gradation type due to the migration of fine materials toward the bottom surface during compaction, and therefore the bottom surfaces are mostly similar to one another. Additionally, it has also been observed that fine-graded mixtures provide higher microtexture values and lower macrotexture values when compared to coarse-graded mixtures. The study helped conclude that the difference between friction and texture values measured on top and bottom surfaces of asphalt concrete specimens is significant.

Correlate aggregate angularity characteristics to the skid resistance of asphalt pavement based on image analysis technology

The impact of aggregate morphological characteristics plays a key role in the skid resistance of road surface due to driving safety and cost benefits. The 2nd generation of the Aggregate Imaging Measurement System (AIMS II) and X-ray Computed Tomography (CT) were utilized to evaluate the shape of particles and capture the change in their morphological characteristics. The Los Angeles Abrasion (LAA) Test was also conducted in this paper to investigate the influence of variations in aggregate angularity on the resistant performance of asphalt mixtures. Before and after 100, 300, 500, and 1000 rotations of LAA polishing process, 48 particles from each different size were adopted and measured using AIMS II and XCT to obtain the value of their morphological properties. The parameter gradient angularity (GA) with AIMS II and three-dimensional angularity (3DA) with XCT of aggregate surface area were proposed from these tests. Analysis of Variance (ANOVA) was employed to compare these two image analysis systems. Conventional experiments including the sand patch test and British pendulum test, were applied using the prepared aggregates to establish a correlation between the morphological properties of grains and the parameters related to the skid resistance of asphalt mixtures. It was found that the resistance performance of asphalt mixtures can be well described with a function using the value of morphological properties through regression analysis. The efficacy of the X-ray CT analyzing system was verified to evaluate the performance of asphalt mixture pavement precisely. The changes in morphological characteristics of particles are the main causes for degradation in the skid resistance of asphalt pavement.

Evaluating the asphalt pavement's surface characteristics by field testing

Pavement management systems are crucial because of monitoring the current pavement condition to supply safe, efficient, comfortable and durable riding surface for vehicles. Driving safety is the most important issue, which is closely related to pavement surface texture. The texture of the pavement surface and its ability to resist the polishing effect of heavy traffic is an important parameter in providing necessary skidding resistance during the service life. In this study, 4 different asphalt pavement sections located in Izmir/TURKEY with having different traffic characteristics were investigated every three months for two years aiming to evaluate the effect of traffic volume on the surface textural and frictional properties of the pavement. The textural properties were evaluated using sand patch test (SPT) and a 3D Laser Scanning System (LSS), while Dynamic Friction Tester (DFT) was employed to assess the frictional properties. As a result, lower Mean Texture Depth (MTD) and Mean Profile Depth (MPD) values were obtained for the increased traffic volumes. High correlation was derived between macro and micro textural properties of the asphalt pavement. Additionally, the textural and frictional properties were found highly related for the investigated asphalt pavement surfaces.

Design of a porous concrete mixture for drainage coverslab in pedestrian walkways

A novel design of a drainage coverslab in pedestrian walking areas has been developed as a composite section of reinforced concrete and a porous concrete layer. Porous concrete exhibits a reduction in permeability due to clogging by particulates, which severely limits the functional level of the coverslab. Slabs were tested for sever clogging mechanism in the laboratory. Samples of new coverslabs with various sizes of aggregates were cast using various compaction methods. Strength was tested using 3 point load test and clogging potential of cover slab was determined by infiltration test (ASTM C1701). Infiltration was tested on a series of coverslab samples which were clogged with top soil mixture collected from the field, landscape fine compost and silt clay slurry to simulate worse case clogging in the field. Comparison of surface textures of the porous surface was made based on sand patch test and proposed clay patch test. This paper focuses on discussing the design of porous concrete layer of coverslab, construction methods and practical issues related to application and mitigation techniques.

Field evaluation of a handheld laser meter for pavement surface macro texture measurement

ABSTRACT In the past, pavement surface texture has primarily been measured using volumetric methods, with the sand patch test the most common. However, handheld laser-based devices are now available for measuring a surface profile depth, which is converted to an estimated surface texture. Comparative measurement of 21 different pavement surfaces, of six different types, indicated that the results were consistently less variable for the laser-based device, compared to the sand patch results. The standard (linear) conversion from laser meter profile depth to estimate texture depth was adequate for typical asphalt surfaces (surface texture 0.5–1.5 mm) but an alternate (quadratic) conversion was recommended for better agreement between the laser meter and sand patch results for surfaces with lower (<0.5 mm) and higher (1.5–3.0 mm) surface textures.

Study on Road Performances of Ultra-thin Wearing Layer Small Particle Size Asphalt Mixture

In order to find out that if it is available to apply the asphalt mixture with small particle size and large porosity to the ultra-thin wearing layer, a kind of open-graded asphalt mixture whose nominal maximum aggregate size is 4.75mm and void ratio is greater than 20% is designed in this article. The rutting test, low-temperature bending test, freeze-thaw split test, pendulum friction coefficient test, manual sand patch test and permeability test are conducted to evaluate the road performance and surface behavior like high-temperature stability, low-temperature, water stability, friction and permeability. The test results shows that the asphalt mixture’s 60℃ dynamic stability is 8201 times /mm, ultimate bending strain is 2896 μe, the residual strength ratio of freeze-thaw split is 83.94%, BPN is 69, the texture depth is 0.71mm, and water permeability coefficient is 6857mL/min. It can be concluded that the asphalt mixture with small particle sized aggregate and large porosity has good road performance, whose high-temperature stability, anti-skid performance and drainage performance are excellent. Compared with road performance of OGFC-13, small particle asphalt mixture can also be used as ultra-thin wearing course.

How concrete removal techniques affect the bonding between concrete and repair mortar

Many bonding failures between the substrate and repair mortar are attributed to too aggressive removal of the contaminated concrete and incorrect use of repair materials. To this end, in this study the effect of concrete removal techniques on substrates of different compositions and, as a result, on the bonding with repair mortar has been investigated. Substrate surfaces of different concrete compositions, micro-concrete (MC) and crushed stone concrete (CC), were treated by using three commonly used techniques: grit blasting (GB), jack-hammering (JH), and hydrodemolition/water-jetting (WJ). Automated Laser Measurements (ALM), sand patch tests and surface tensile strength measurements were applied to characterize the substrate surface. According to the results, the co-lateral effects of removal techniques such as WJ are dependent on the concrete mix composition. Moreover, WJ- and JH- treated samples achieved a lower surface tensile strength and bond strength compared to GB-treated slabs.

Performance Evaluation of Slurry Seals Containing Reclaimed Asphalt Pavement

Preventive pavement maintenance methods such as slurry seals are cost-effective treatments that increase the longevity of pavements. The incorporation of recycled materials such as reclaimed asphalt pavement (RAP) into asphalt pavement helps to further reduce costs and energy consumption. The present research studied the feasibility of incorporating RAP into slurry seal mixtures or RAP slurry seals. Two slurry seal mixtures containing cement and hydrated lime as fillers were tested. The first mixture comprised slurry seal made with virgin aggregate and the second used RAP as the aggregate. The wet track abrasion test (WTAT) and loaded wheel test (LWT) were conducted to evaluate the performance of the mixtures. Wet cohesion and friction tests (sand patch and British pendulum) were performed on the selected slurry seal mixtures with the best performance under WTAT and LWT. The results show that it is possible to prepare slurry seal containing RAP. Although the curing time relative to the virgin aggregates increased by 1 h for RAP aggregate, the wear value in the WTAT decreased by half. Lateral displacement and the British pendulum test results improved considerably for slurry seals made with RAP aggregates. The results of the sand patch test on WTAT samples showed that slurry seals made with RAP should be lightly rolled after lay-down to improve their friction life. Cost analysis indicates that the use of RAP as an aggregate in slurry seal decreased costs by up to 14%. RAP slurry seal showed better overall performance with lower cost than the virgin slurry seal.

Evaluation of Fine Aggregate Morphology by Image Method and Its Effect on Skid-Resistance of Micro-Surfacing.

Micro-surfacing is a widely used pavement preventive maintenance technology used all over the world, due to its advantages of fast construction, low maintenance cost, good waterproofness, and skid-resistance performance. This study evaluated the fine aggregate morphology and surface texture of micro-surfacing by AIMS (aggregate image measurement system), and explored the effect of aggregate morphology on skid-resistance of single-grade micro-surfacing. Sand patch test and British pendulum test were also used to detect skid-resistance for comparison with the image-based method. Wet abrasion test was used to measure skid-resistance durability for feasibility verification of single-grade micro-surfacing. The results show that the effect of Form2D on the skid-resistance of micro-surfacing is much stronger than that of angularity. Combining the feasibility analysis of durability and skid-resistance, 1.18–2.36 grade micro-surfacing meets the requirements of durability and skid-resistance at the same time. This study also determined that, compared with British pendulum test, the texture result obtained by sand patch test fits better with results of image method.

Effect of fine aggregate angularity on skid-resistance of asphalt pavement using accelerated pavement testing

The effect of fine aggregate angularity (FAA) on the skid-resistance of asphalt pavement was investigated in the paper. To achieve the objective, four fine aggregates with various FAA values were used in stone matrix asphalt (SMA) and conventional asphalt concrete (AC), separately. The Model Mobile Load Simulator (MMLS3) was used to simulate the effect of traffic load on the skid-resistance of compacted mixes. After specific loading cycles, the skid-resistance of asphalt mix slabs was measured using the Sand Patch Test and the British Pendulum Number (BPN) Test. Sand Patch testing mainly explores the macro-texture of the pavement, while BPN test mostly investigates the micro-texture of the pavement. The test results show FAA has a significant impact on skid-resistance on the macro-texture level but an only marginal influence was observed on the micro-texture level. The correlation between FAA and skid-resistance is validated using a Forward Selection method. Outcomes of this experimental study can potentially be adopted by both practitioners and researchers.

Determination of Surface Roughness Parameters by Optical Profilometry and Sand Patch Test

In cases when two concrete parts are cast against in different times are not connected by dowels, main contributors to the resistance are cohesion and friction. Shear resistance of the interface is highly dependent on surface treatment and its roughness. In this paper, besides the review of available methods of surface roughness determination, the optical profilometry will be introduced and described. Optical profilometry represents non-contact and non-destructive method for characterizing surface topography. Furthermore, results obtained by abovementioned method will be compared with Sand Patch Test, in order to determine its usability and limitations.

Comparative laboratory evaluation of macro texture depth of surface coatings with standard volumetric test methods

In this research, macro texture depth of surface coatings including chip seals and slurry seals were evaluated with two volumetric test methods. Chip seals and slurry seals, one hundred in total, were manufactured with different aggregate types and grading sizes. Mean texture depths (MTDs) of each sample were computed via sand patch and outflow meter tests according to ASTM E 965-12 and ASTM E 2380-12, respectively. Applicability of both test methods was examined and relative differences in MTDs for chip seal and slurry seal samples were determined as 21% in average. As a result, each test method is able to specify the MTDs with increasing aggregate sizes; whereas 6mm MTD can be identified as a threshold for implementation of outflow meter test.

The Influence of Aggregate Lithological Nature on Pavement Texture Polishing: A Comparative Investigation on a Test Site in Southern Italy

Abstract Pavement surface performance plays a key role in tyre-road interaction phenomena and greatly affects road safety, vehicle's operational costs, and environmental sustainability. Surface texture and friction change over time with the action of the repeated passage of vehicle tires, especially those of heavy vehicles (long-term variations). Other factors related to asphalt mix composition, primarily the aggregates and their mineralogical composition, the binder and their combination, have a great effect on micro and macrotexture evolution. In particular, the extent to which a surface will polish depends on both the level of traffic and the ability of the aggregate to resist polishing. Moreover, an aggregate may provide different levels of skid resistance depending on where it is used because the polishing effect is also influenced by other stresses such as braking and cornering forces. In light of the above, this paper focused on a 4-year monitoring of a test site (both straight and curve sections) with four different dense graded friction courses designed and produced with aggregates of different petrographic nature: limestone, basalt, and expanded clay. Several devices and test methods (Skid Tester, Sand Patch Test, Laser Profilometer) were used in order to investigate skid resistance and macro-texture progression. Results showed that: (i) mixes have a different microtexture deterioration behavior in relation to aggregate type, especially during the pavement early life, confirming how limestone does not perform as well as basalt or expanded clay under traffic actions; (ii) macrotexture evolution trend is characterized by a consistent decrease after 4 years; the maximum value of macrotexture was registered 13 months after opening to traffic (when the migrated bitumen is completely removed by traffic). Results highlighted practical applications and perspectives for both practitioners and researchers.

Performance of Micro Surfacing on Expressway

Micro surfacing is developed from a slurry seal technique. It is a mixture of polymer modified bitumen emulsion with 9.5 mm chipping, quarry dust, cement, additive and water. The emulsion used in micro surfacing is CQS-1h and added with natural latex as its polymer modifier. This study was carried out to evaluate the performance of micro surfacing applied on the expressway. In 2008, a number of preventive maintenance projects in North South Expressway used micro surfacing especially in the northern region. This study involved particular sections of expressways located at km 58.60 to km 59.60 south bound and km 84.60 to km 85.60 southbound from Bukit Kayu Hitam. The Portable Pendulum Tester was used to evaluate skid resistance performance while the texture depth of micro surfacing was measured using Sand Patch Test. The surface irregularities data was collected using a 3 m rolling straight edge while the rutting measurement was based on 3 m static straight edge. The measurements were carried for every 3 months starting from April 2009 to 1 year of the operation period. The result shows that the skid resistance, texture depth, surface irregularities and rut depth for micro surfacing comply with the specification requirements after one year of operation. The pendulum test value obtained is greater than 46 with a texture depth of 0.50 mm. The average number of surface irregularities is below 4.0 mm while the rut depth average value is less than 5.0 mm. This study shows that the micro surfacing was performing well on the expressway. It has proven effective in restoring friction characteristic, filling ruts and re-establishing the transverse profile of road surface.

Comparison of Sand Patch Test and Multi Laser Profiler in Pavement Surface Measurement

Pavement surface texture has been assessed with variety of test methods such as sand patch test and multi laser profiler. In recent years, road administrations face the issues of handling data acquired by totally different methods and the inconsistent correlation between different methods. Therefore, the objective of this study is to determine and compare the texture depth value of road pavement measured by different methods namely sand patch test and multi laser profiler. This paper compares the results of two measurement methods for pavement surface macro texture which referred as mean texture depth (MTD). Tests were conducted along North–South Expressway, between km 110.5 and km 107.2 (Southbound). T-test analysis shows that there is statistically significance difference on the result obtained between these methods along emergency lane. However for slow lanes,it was found that there is no significance between sand patch test and laser based measurement. Regression analysis shows that the coefficient of correlation, R obtained from emergency lane is 0.3719 and slow lane is 0.4579. These results generally conclude that there were weak correlations between the result of these two measurement techniques.

Effect of Rainfall Intensity and Road Crossfall on Skid Resistance of Asphalt Pavement

Skidding is one of the major factors to road accidents during wet weather condition. Skidding during wet weather happens when water film presents between the tyre and pavement reducing the friction of tyre onto the road surface. This laboratory study was carried out to investigate the factors affecting Pendulum Test Value on Asphaltic Concrete surfaces. The main objective of this study is to determine the pavement type and the crossfall percentage that best resist skid during wet weather condition. Three different types of dense graded mixes were used in this study which are AC10, AC14 and AC20. Those three constructed mixes were tested using Sand Patch Test (SPT) and were then subjected to various rainfall conditions and crossfall percentages using Rainfall Simulator. The rainfall conditions are categorized as low rainfall, medium rainfall and high rainfall while the crossfalls were increased 2% from 0% to 10% crossfalls. During the event of rainfall on each pavement surfaces, a British Pendulum Tester (BPT) was used on the pavements to obtain the Pendulum Test Value (PTV) at different crossfalls. Collected data are analyzed using analysis of variance (ANOVA) to justify the objectives. Results from PTV shows that 4% to 10% crossfall is the best crossfall and AC20 is the best surface type in resisting skid.

Laboratory and In Situ Investigation of Chip Seal Surface Condition Improvement

This study focuses on determining the effect of different types of binder and aggregate on chip seal performance in both laboratory and in situ settings. Eight different chip seal test sections were constructed on existing asphalt concrete as the pavement preservation technique of choice. Two different binders, CRS-2L modified emulsion and B100/150 penetration hot asphalt cement, were used in the test sections. Also, two types of aggregate, limestone, and basalt, were used. The sand-patch test as well as visual evaluations was conducted on the test sections regularly. In addition to physical and chemical characteristics, the adhesion resistance of the utilized materials was determined in the laboratory and compared with the test section results. The loss of aggregate (also called raveling or shelling), bleeding deteriorations on each test section were evaluated over time in respect to binder and aggregate type. The results indicate that after chip seal construction, the macrotexture of the existing asphalt concrete increased significantly. It was also determined that CRS-2L chip seal showed better performance than B100/150 penetration hot asphalt cement. With regard to the type of aggregate used for the chip seal, limestone showed better raveling performance when compared with basalt. In addition, in the test sections, the right and left lanes demonstrated different levels of severity distress because of varying traffic distributions. It was also seen that macrotexture is one of the best parameters to determine chip seal performance and to follow its progress over time.

Effect of aggregate shape on the surface properties of flexible pavement

One of the most important properties of flexible pavements in terms of tire-pavement interface is surface texture. The texture of a pavement surface and its ability to resist polishing effect of traffic is of prime importance in providing skidding resistance. Pavement surface texture greatly contributes to tire-pavement skid resistance which has a direct effect on traffic operation and safety particularly at high speeds. Doubtless, there exists a close relationship between pavement surface texture and aggregate angularity within the wearing course. This paper is aimed to determine the effect of aggregate shape on the surface properties of Hot Mix Asphalt (HMA). Two different mineralogical types of aggregate (basalt and limestone) have been crushed with impact, jaw and roll type of crushers. Various types of aggregate with different shapes have been mixed with 50/70 penetration grade bitumen to form dense graded mixtures. Test methods related with the evaluation of shape and texture characteristics have been utilized to characterize the geometrical properties of aggregates. The texture and friction properties of asphalt slabs have been evaluated by means of sand patch test, 3D laser scanner and dynamic friction tester respectively.