Browsing by Subject "Pavements"
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Item Accounting for the effects of rehabilitation actions on the reliability of flexible pavements: performance modeling and optimization(2009-05-15) Deshpande, Vighnesh PrakashA performance model and a reliability-based optimization model for flexible pavements that accounts for the effects of rehabilitation actions are developed. The developed performance model can be effectively implemented in all the applications that require the reliability (performance) of pavements, before and after the rehabilitation actions. The response surface methodology in conjunction with Monte Carlo simulation is used to evaluate pavement fragilities. To provide more flexibility, the parametric regression model that expresses fragilities in terms of decision variables is developed. Developed fragilities are used as performance measures in a reliability-based optimization model. Three decision policies for rehabilitation actions are formulated and evaluated using a genetic algorithm. The multi-objective genetic algorithm is used for obtaining optimal trade-off between performance and cost. To illustrate the developed model, a numerical study is presented. The developed performance model describes well the behavior of flexible pavement before as well as after rehabilitation actions. The sensitivity measures suggest that the reliability of flexible pavements before and after rehabilitation actions can effectively be improved by providing an asphalt layer as thick as possible in the initial design and improving the subgrade stiffness. The importance measures suggest that the asphalt layer modulus at the time of rehabilitation actions represent the principal uncertainty for the performance after rehabilitation actions. Statistical validation of the developed response model shows that the response surface methodology can be efficiently used to describe pavement responses. The results for parametric regression model indicate that the developed regression models are able to express the fragilities in terms of decision variables. Numerical illustration for optimization shows that the cost minimization and reliability maximization formulations can be efficiently used in determining optimal rehabilitation policies. Pareto optimal solutions obtained from multi-objective genetic algorithm can be used to obtain trade-off between cost and performance and avoid possible conflict between two decision policies.Item Application of relational database principles for rating bituminous coarse aggregates with respect to frictional performance(Texas Tech University, 2000-08) Rachakatla, PrasannaThe design approach that is commonly employed to ensure satisfactory skid resistance of bituminous pavement surfaces is to control the quality of coarse aggregates used in pavement construction. Traditionally, state and federal highway agencies have relied on the results of laboratory tests for this purpose. Among the laboratory tests, those commonly used are Polish Value Test, Acid Insoluble Residue Test and Petrographic Analysis. The findings from many research studies indicate that the reliability that can be achieved by using a single laboratory test is poor. In the current research study at Texas Tech, a comprehensive laboratory and field test program was undertaken with the objective of developing an improved procedure for predicting field skid resistance performance of bituminous aggregates. The field test program included monitoring of 55 pavement test sections that were located in various climatic zones within the state of Texas over a 3-year study period. As a part of this monitoring program skid resistance of the pavement at 64 km/h, British pendulum number, and pavement macrotexture were measured. The laboratory test program consisted of complete characterization of the pavement coarse aggregates using the following test methods: Polish Values Test, Magnesium Sulfate Test, LA Abrasion Test, Acid Insoluble Residue Test and Petrographic Analysis. The skid resistance data collected over the 3-year study period was then used to develop a "Skid Performance Rating" for each pavement section. Subsequently appropriate statistical analyses were conducted to develop regression models that related skid performance rating to various laboratory test parameters. The findings revealed that a better correlation is obtained when aggregates are categorized into sub-groups that contain aggregates with similar mineralogical makeup. Accordingly, aggregates were categorized based on percent carbonate minerals and the Acid Insoluble Residue. Statistical regression models were then developed for each aggregate category. As an alternative means, historical data on skid resistance of pavements constructed with a given aggregate can be used in the evaluation of aggregates. This alternative procedure is used by TxDOT to overcome the shortcomings of using laboratory test data. Highway agencies may use either of the above mentioned procedures to evaluate the performance of an aggregate source for use in constructing pavement test sections. A combination of the two approaches mentioned above may result in predicting field skid resistance on pavement surface courses with a greater degree of reliability. However, an approach that uses these two methods involves dealing with a large amount of laboratory and field test data. A user may find it extremely difficult and cumbersome to maintain and use this information to reliably predict the skid resistance of pavement test sections. In order to achieve the objective of faster reliable prediction of aggregate field skid performance, a application tool was developed. This application, 'SKIDRATE', was specifically designed to address the problem of predicting skid resistance on Hot Mix Asphalt Concrete (HMAC) pavement surfaces. SKIDRATE combines Relational Database Management Systems (RDBMS) principles and statistical regression techniques to evaluate aggregate sources to be used in the construction of HMAC pavement surfaces. An Entity-Relationship Data model was used to analyze and design the RDBMS. Important entities and association among the entities were identified along with the respective cardinalities of the association. Primary and foreign keys were determined for the relations in the RDBMS. The relations were normalized to 3NF in most of the situations. The application enables the storage of data about the aggregate source, results of laboratory tests and details of field skid testing. Users of the application can retrieve the required information on any given aggregate source and process the data using the results of a comprehensive statistical regression analysis that is integrated within the application. This integration of database technology and statistical regression analyses facilitates fast, easy and reliable interpretation of the field and laboratory test results. The application can be used as a convenient tool by engineers in transportation departments to evaluate the suitability of an aggregate for use in pavement surface courses.Item Bayesian estimation of finite mixture roughness model(2016-12) Serigos, Pedro A. (Pedro Antonio); Prozzi, Jorge Alberto; Zhang, Zhanmin; Gilbert, Robert B; Müller, Peter; Mikhail, MagdyHighway infrastructure systems provide a crucial service to society and constitute a major asset with a significant maintenance and rehabilitation cost, highway pavements comprising a major component of the total cost. The increasing need for greater capital investment, in the face of ever-decreasing federal funding to maintain highway infrastructure, highlights the importance of developing and implementing effective methods for managing pavement assets. A key for the success of pavement management is to accurately predict the future condition of the pavements in the network. This dissertation proposes a mixture of regression models to capture the systematic differences in pavement performance not explained by variables typically available in pavement management systems. This approach assumes that the heterogeneous pavement performance, which results from the combined effect of the several unobserved factors and interactions, is manifested through a finite number of latent groups. The estimation of the proposed model allows for defining the parameters of the group-specific models while clustering the observations into the latent groups. The insights provided by the model-based clustering of performance data can also be incorporated into the design of maintenance and rehabilitation strategies, as clustering of sections according to their deterioration rate allows for identifying pavements in the network with structural deficiencies and tailoring actions in response. The gain in model fit, along with the insights provided by the proposed methodology for the unsupervised model-based clustering of pavement performance was demonstrated using experimental data. In addition, the proposed mixture model was applied to develop a Bayesian pavement roughness model specified with variables from an existing pavement management system, plus climatic and preventive maintenance variables, and estimated using nationwide field data from the Long-Term Pavement Performance program. Lastly, the developed roughness mixture model was calibrated for Texas pavement conditions by combining both the nationwide data and data extracted from the processing and merging of various Texas Department of Transportation databases. The proposed methodology produces accurate predictions of the progression of roughness as well as robust estimates of the factor effects driving the deterioration of pavements, which, ultimately, lead to a more efficient management of highway assets.Item Characterization of waste recycled glass as a highway material(Texas Tech University, 1996-08) Viswanathan, KrishnanThe success of glass recycling programs has resulted in an oversupply of waste recycled glass or glass cullet. The properties and strength of glass cullet aggregate mixes are influenced by maximum size of cullet, cullet content in the mix, type of conventional aggregate, and also the debris level in the cullet. A survey of State DOTs was done to determine their experiences with the use of glass cullet. Also, a survey among suppliers of cullet in Texas was done to determine the costs associated with procuring glass cullet. Based on these surveys, glass cullet was identified for use in base course, subbase, subgrade and embankments and also for backfill applications. A test program was devised to test the engineering suitability of glass cullet samples for the above mentioned applications. Stripping tests were also done to determine the adhesion of glass cullet and asphalt in the presence of water. Based on the results of these tests, it was found that glass cullet has properties similar to natural aggregates and could be used as a highway material. Specifications for use of glass cullet by the Texas Department of Transportation were also developed.Item Comparative analysis between the magnesium sulfate soundness and micro-deval tests in the evaluation of bituminous aggregates(Texas Tech University, 2000-05) Phillips, William FrankIn the past ten years, several factors have led the Texas Department of Transportation (TxDOT) to reevaluate the way it designs bituminous pavements. Foremost has been the increase in the volume of heavy truck traffic and the permitted loads they are allowed to carry. Among the highway pavements designed and constructed by the Department, Asphaltic Concrete Pavement (ACP) is the most commonly specified type of bituminous pavement. Changes in the design of ACP have been seemingly small and incremental but if we step back and consider the wider view of what has evolved during this time, the changes are significant, particularly in the quality of aggregates needed to develop an acceptable bituminous mix. The quality of aggregates used in bituminous mixes is a primary factor that determines in the performance of these pavements. New and innovative designs have raised the bituminous pavement construction process to higher levels. These designs provide us with pavements that are structurally superior to traditional ACP. CMHB, SMA, and Superpave designs are coarse, open graded mixes with fewer fines and higher asphalt contents. These bituminous mixes demand even higher quality in aggregates due to their rock on rock contact that exist in the mix. These changes will provide Texas with highways that will have longer design lives, require less maintenance and will be more cost effective in the long term. Establishing specification requirements that meet the design criteria is of utmost importance. Having the means to insure compliance with the specifications is equally important. As the Department has modified both the procedures and the requirements for bituminous mixes, the contracting industry has had to adapt. This has introduced a level of uncertainty, which lends itself to an increased risk that the contractors must account for. One of the greatest risks that a contractor is faced with when bidding a job is the selection of an aggregate source. This is one of the factors that led to higher unit bid prices for bituminous mixes. To meet this challenge, the Department must have quality control tests that are accurate, timely, and repeatable. The majority of the aggregate test methods used today were developed in the 1930's and 1940's. The relationship between the performance of aggregates in the laboratory and in the field was not well defined when these tests were developed and remains ambiguous today. One of the primary indicators of durability and resistance to degradation has been the Magnesium Sulfate Soundness (MSS) Test.Item Determination of potential vertical rise in expansive soils using centrifuge technology(2015-08) Snyder, Larson Mackenzie; Zornberg, Jorge G.; Cox, Brady RExpansive soils are a significant issue in Central Texas due to a high potential to shrink and swell which leads to cracking of roadways. A significant amount of research has been conducted on expansive soils, which has led to the development of direct and indirect methods to determine a soil’s swelling potential. The methods for direct measurement of the swell potential are typically both time consuming and expensive, which has led to the underutilization these methods. Indirect methods, which use index geotechnical properties to predict the swelling behavior of a soil, are empirically based correlations that are only approximations that don’t take into account variables such as the mineralogical composition of the soil and include the Texas Department of Transportation's (TxDOT) approach, Tex-124-E, which is based solely on Atterberg Limits and grain size distributions to determine the potential vertical rise of an expansive deposit beneath a pavement system. The purpose of this study is to develop an approach that both directly measures an expansive soil’s swelling potential using centrifuge technology (DMS-C) and determines a potential vertical rise (PVR) for use in site characterization. This study consists of eleven soils sampled from ten sites in Bexar, Atascosa, and Guadalupe Counties of the San Antonio TxDOT district to determine the PVR using the DMS-C and Tex-124-E approaches. Soil characterization tests were conducted including Atterberg Limits and compaction tests, as well as, over 300 specimens tested in the centrifuge testing program. The centrifuge testing program consisted of compacting samples into the double infiltration setup at initial conditions of 3% dry of optimum moisture content and 100% relative compaction and testing the samples at three separate artificial g-levels that correlate to three effective stresses to generate a swell-stress curve that was defined over a range of stresses typically found in the active zone. The results from the centrifuge tests for samples from each site are verified with the traditional free swell tests (ASTM D4546.) At each site, the swell-stress curve and stresses for the soil profile were used to determine the PVR for the DMS-C approach. From the results, seven of the sites received a high or severe degree of concern for potential damage to the pavement. Of these seven sites, six of the sites correlated to soils derived from the Navarro/Marlbrook Formation, which is a major geologic formation in both the San Antonio region as well as the rest of Central Texas east of the Balcones Fault zone. The same stresses, as well as, the liquid limit, plastic limit, and moisture content are used to predict the PVR with the traditional Tex-124-E approach. These results were analyzed and compared to the values to the PVR from the direct measurements taken in the DMS-C approach for each site. From the comparisons, the approximate prediction of PVR for Tex-124-E does not correlate to the direct measurements of swelling results to determine the DMS-C approach. Furthermore, the characterization the swell potential using the centrifuge for PVR calculation with the DMS-C approach was proven to be expeditious and can lead to a significant amount of savings by reducing maintenance and repair of damage. Thus, the DMS-C approach should be implemented into the protocol for the determination of potential vertical rise of expansive soils to more accurately determine whether a given location will be problematic.Item Evaluation of asphalt--aggregate bond and stripping potential(Texas Tech University, 2004-12) Das, Subrata KumarOne of the primary deterioration mechanisms of asphalt concrete is the de-bonding of asphalt from aggregate in the presence of moisture. This distress mechanism is also referred to as stripping. It is a very complex process of moisture damage that is caused by several factors, including the characteristics of asphalt cement and aggregate as well as environmental conditions. This research evaluated the interfacial bonding mechanisms and stripping potential of aggregate-asphalt binder combinations commonly used by Texas DOT in maintenance seal coats. This evaluation was conducted using two test procedures; Net Adsorption Test and TechMRT Pull-Out Test. Results from this evaluation will help improve the performance of seal coats and HMA pavements in Texas.Item Evaluation of the curing time and other characteristics of prime coats applied to a granular base(2011-05) Mohan, Gouri; Stokoe, Kenneth H.; Yildirim, YetkinPrime coats have been in use for many decades to help protect the base before the subsequent application of bituminous surface treatments. Prime coat is an application of a low viscosity binder onto the base to help protect the base from moisture, to provide an adequate bond between the bituminous surface coating and the base, to strengthen the base near the surface by binding the fines, and to protect the base from detrimental effects of weather and light traffic until the surface can be constructed. For a prime coat to function efficiently it should penetrate sufficiently into the base and should be cured before the application of subsequent layers. Evaluation of the time required for curing of prime coats and how the curing time depends on various weather parameters has received a lack of attention. In view of this, the time taken for curing of different prime coats and the dependence of curing time on weather parameters was studied. The prime coats most commonly used in Texas were selected for this study, namely; MC-30, EC-30, CSS-1H, SS-1H and AEP. All testing was done in real conditions, that is, samples were prepared and exposed to actual weather conditions. Since each prime coat is chemically very different, they were analyzed separately to determine the minimum curing time. Curing time was calculated in three different weather conditions to understand how the weather affects curing time. Further, two different application methods were used to determine the effect of application method on the curing time. In addition to determining curing times, other important engineering properties of prime coats that determine the performance of prime coats such as strength, permeability and penetration were also studied. Strength and permeability tests were done on cured specimens and the effect of application method on these values was also determined. Strength values were measured using a pocket penetrometer and penetration was determined by using sand penetration tests. A unique ranking system list was developed using curing time, strength, penetration and permeability as the key factors to determine the prime coat which would serve all the intended functions effectively and efficiently.Item Feasibility of using the micro-deval test method as an aggregate production quality control tool(Texas Tech University, 2003-12) Hoare, Appa RaoNot available.Item Field performance of geogrid reinforced low-volume pavements(2010-05) Joshi, Rutuparna Vidyadhar; Zornberg, Jorge G.; Prozzi, Jorge A.For the past three decades, geosynthetics have been recognized as materials that can significantly improve the performance of pavements on weak subgrade. Pavements exhibit non-linear elasto-plastic behavior. The addition of geosynthetics is undoubtedly beneficial. This being said, researchers have concentrated more on lower life cycle cost and high benefit-cost ratio whereas much less attention has been given to the complex behavior of the reinforced pavement system. Comprehension of the short-term and long-term field performance of reinforced pavements under continued traffic and cyclic environmental loading has remained unexplored. There is empirical evidence indicating quantitative benefits of reinforced versus unreinforced pavement structure. However, quantification of the relative benefits of different types of reinforcement like geogrids and geotextiles lacks information. Further, evaluation of the benefits and comparison of chemical stabilization in the form of lime treatment with mechanical stabilization in the form of reinforcement for pavements on soft soils has received lack of attention. In view of this, full-scale instrumented reinforced and lime treated pavement sections with different schemes were studied. Regular Falling Weight Deflectometer (FWD) testing was conducted in a Farm-to-Market Road, in Grimes County, Texas. Three different geosynthetic products were used for base reinforcement and lime treatment was used for subbase stabilization. Deflection measurements for 9 field trips in 3.5 years were evaluated. Modified deflection basin parameters (DBPs) were defined to typically identify layer properties and were used to measure the relative damage to the base, subbase and subgrade for different sections. A modified Base Damage Index (BDI) and a modified Base Curvature Index (BCI) were defined as a part of this study to capture the benefit of reinforced base and lime stabilized subbase respectively. The variation in the DBPs over three periods of wetting and drying along with explanation of the observed trends forms a part of this research. In addition, a number of condition surveys were performed, during 3 years, to visually identify distresses in various sections. A unique distress quantification technique was developed for measuring deterioration of the pavement sections in terms of the observed distresses and FWD measurements. With this, an index of pavement performance was developed. Thus, the FWD deflection data analyses complemented by visual observation, reveals important information on performance of different geosynthetics with the same base course. Analysis of the field performance of the multiple experimental sections throws light on the relative merits of base reinforcement against lime stabilization.Item Influence of aggregate surface characteristics on pavement performance(Texas Tech University, 2003-12) Khan, Jabed Riyad; Senadheera, Sanjaya; Hossain, ShabbirAggregate surface characteristics such as texture, shape, surface electrical charge, and mineralogy affect the performance of Portland cement concrete. Negative performance of concrete pavement such as spalling is greatly influenced by material characteristics and environmental factors. Surface characteristics of aggregate play a major role in occurrence of spalling in the concrete pavement. Previous studies show that concrete pavements with siliceous gravel aggregates develop more spalling problem than that of with limestone aggregate as siliceous aggregates show more affinity to water due to a preexisting electronegative charge on their surfaces. Better aggregate-cement bonding at the interfacial region will reduce the spalling problem. Several researches have been taken places in the past and are still going on to improve the aggregate-cement paste bonding by improving the interfacial microstructure. Use of surface treatment agent on aggregate surface might produce positive result in this regard. In this research, numbers of specimens were prepared for different types of surface treatment agents on siliceous aggregate surface. Elemental compositions of the specimens at the interfacial region were analyzed using Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). Hydrated lime as a surface treatment showed improvements in the microstructural composition at the interfacial region. Silica fume also showed similar results. Fracture toughness test on the beam with lime treated aggregate showed better performance than normal concrete beam and the beam with silica fume as admixture only. Lime treatment on aggregate surface produce more fatigue resistant and durable concrete against spalling.Item Influence of construction water quality on the performance of road base and subbase materials(Texas Tech University, 2004-08) Bhongir, Chandra PrakashIn some parts of Texas, during periods of draught and increased construction works, water has become a precious commodity, especially for areas in the state which receive very little rainfall. This puts the construction projects on-hold, which requires large quantities of water. One way to reduce the demand for drinking water is to substitute non-drinking quality water in construction applications. However, there may be some adverse impacts of using alternative water in construction applications. The research included the study of most critical concerns that would arise when water from alternative water sources is used in the construction of road bases and subbases. These concerns are: (a) the potential impact that soluble minerals in alternative water may have on soil parameters that are used in material selection (i.e., Atterberg Limits and Bar Linear Shrinkage) and (b) the effect that sulfate ions in water may have on the potential for sulfate heave in base layers stabilized with calcium-based stabilizers. A comprehensive test program was undertaken selecting five different soils, which would cover the broad range of soil types found within the geographic parts of Texas. The types of alternative water used were Treated Effluent from Wastewater Treatment Plants, Ocean Water, and Brine Water, each having different concentrations of salinity and sulfates. The soil samples were tested with and without adding alternative water to evaluate the impact of alternative water on the soil samples. A predictive model was developed that would allow preliminary evaluation of candidate alternative water sources to determine their suitability.Item Issues in the statistical modeling of data with application to the skid resistance data(Texas Tech University, 1996-12) Blevins, Krista S.Previous research studies have indicated that polish value may not be a good predictor of actual skid performance of pavements. In this study, data on skid performance was used to build a model to predict skid numbers at 40 mph for different pavements in different climates and different regions of Texas. The data provided for analysis included mean British pendulum number, texture measurements, vehicle passes per lane, polish value, LA abrasion test results, magnesium sulfate test results, acid insoluble residue test results, chmate region and the mixture of aggregate in the pavement. This data was given for the years 1995 and 1996. Since there is no theoretical justification to fit a specific model to the SN(40) data, the strategy adopted for this analysis was to use the method of empirical model building to develop a suitable model for this data set. The techniques of exploratory data analysis are employed to get some ideas about the type of models that may be suitable for this data. The strategy at this stage was to choose the simplest candidate model and then use diagnostic techniques to improve the previous model. After improvement of each stage, diagnostic analyses were performed to check model adequacy or lack thereof.Item Monitoring and performance evaluation of a road reconstruction project with lime stabilized fine-grained subgrade(Texas Tech University, 1997-05) Wright, Norman EdwardThe use of lime as a soil stabilizer is well documented in the literature. From a historical view point, the first project in modern times which used lime was built in 1948 at Fort Sam Houston in Texas. Army roadways had failed and needed to be reconstructed within a limited budget. Lime was used as a cost effective measure and mixed with the existing roadways. The Army constructed the two block section of roadway while the Texas Highway Department conducted the initial laboratory tests (National Lime Association, 1977). Because of the success of the initial project, both the Army and Texas Highway Department have used lime for soil stabilization.Item On Bayesian estimation of spatial and dynamic count models using data augmentation techniques : application to road safety management(2015-08) Buddhavarapu, Prasad Naga Venkata Siva Rama; Prozzi, Jorge Alberto; Bhat, Chnadra R; Scott, James G; Carvalho, Carlos M; Smit, Andre FOver the past several years, roadway safety management has evolved into data-driven or evidence-based science. The corner stone of a data-driven roadway safety management is the knowledge about useful patterns in the complex crash data. Crash data is often difficult to model with several confounding factors and discrete target variables such as crash counts or crash severity. The major goal of this dissertation was to contribute to the methodological realm of roadway safety management. The research objectives are in two folds: 1) to develop state-of-the-art model specifications for modeling crash data, and 2) to develop a probabilistic model-based site ranking framework. This research addresses methodological issues in crash frequency modeling such as unobserved heterogeneity, spatial correlation, and temporal patterns. Two novel specifications were developed to address these methodological issues: 1) negative binomial spatial with random parameters (NBSRP) modeled as multi-variate normal finite mixture distribution; 2) negative binomial spatial model with dynamic parameters (NBSDP). The NBSRP with finite-mixture specification allows for identifying the underlying sub-groups of road segments, and for skewness and multi-modality in the underlying random parameter distribution. The NBSDP specification employs dynamic linear model (DLM) formulation of the discrete negative binomial count model by exploiting recently developed polya-gamma data-augmentation techniques. NBSDP model facilitates to investigate the evolution of the model parameters over the time and to make safety predictions for a future year. Both NBSRP and NBSDP models simultaneously accounts for potential spatial correlation of crash counts from neighboring road segments. Bayesian methods have been widely used for model building and recently gaining further popularity due to the availability of efficient algorithmic techniques for the parameter estimation. Computationally efficient Bayesian estimation frameworks that leverage recent advances in data augmentation techniques were developed in this research to estimate the proposed count specifications. Bayesian estimation methods also facilitate statistical inference on site ranks, thereby allowing for probabilistic ranking. A computationally efficient site ranking framework was developed incorporating the recent probabilistic ranking techniques towards the end of this dissertation. Overall, this dissertation demonstrates the feasibility of designing Bayesian modeling frameworks for probabilistic roadway safety management, which facilitate online learning. The research ideas presented in this dissertation may be extended to bigger networks to test the feasibility of developing a safety management framework that automatically learns from the latest crash data sources over the time.Item Software for the analysis and evaluation of aggregate sources using aggregate frictional properties(Texas Tech University, 1998-08) Nageswaran, BalajiIn this thesis project, software is developed to implement a procedure for rating bituminous pavement aggregates based on expected field skid performance. The above procedure was developed by researchers in the Civil Engineering Department at Texas Tech University. This software analyzes the laboratory test values and field skid measurements corresponding to each aggregate and predicts the field performance rating as well as the terminal skid number for the aggregate. Also, the software is equipped with features to plot graphs and generate reports based on the performance of the aggregates in laboratory tests and field tests. Separate windows are provided for the user to enter information regarding new aggregates, to modify the existing values, and also to delete the existing aggregate records. The graphs plotted and the reports generated can be sent to the printer if the user wishes to have a hard copy of them. Software is tested for its efficiency and accuracy with real data collected by the Civil Engineering Department, Texas Tech University.Item Statistical analysis of bituminous coarse aggregate data(Texas Tech University, 2000-12) Mabie, John W.The Ministry of Transportation in Ontario, Canada (Rogers, C.A., et al,, 1991) and the National Center for Asphalt Technology at Auburn University (Kandhal, P.S., et al., 1998) have performed research studies and have concluded that the Micro-Deval test provides a better correlation between aggregate durability than any other test currently in use. The MSS and the Micro-Deval test procedures were compared in terms of single and multiple laboratory precision. The purpose of this study is to perform the statistical analyses that will be used to determine if a relationship can be found between the two tests so that TxDOT may adopt the Micro-Deval as a suitable alternative to the MSS procedure. Also, a statistical analysis will be performed to determine whether a relationship can be found between the Micro-Deval and Wet Ball Mill procedures. Based on the results from this study, appropriate specification limits will be proposed and recommendations presented concerning the implementation of the Micro-Deval test, for use by the Texas Department of Transportation.