Long-term Performance Monitoring Research Articles

Integrating Tensometer Measurements, Elastic Half-Space Modeling, and Long-Term Pavement Performance Data into a Mechanistic–Empirical Pavement Performance Model

Pavement performance models (PPMs) are utilized to predict pavement network conditions which is an essential part of any sustainable pavement management system (PMS). The reliability of a PMS and its outputs is proportional to the reliability of the PPM used. This article describes a mechanistic–empirical pavement performance model based on pavement response parameters—strains calculated in the pavement layers measured by tensometers embedded in the pavement surface and verified by calculations in the elastic half-space model and supplemented by empirical data from long-term pavement performance monitoring and accelerated pavement testing. Hence, the herein described PPM combines pavement serviceability evaluation, pavement bearing capacity, and the physico-mechanistic properties of paving materials. The analytical methods which were used to ascertain the physico-mechanistic characteristics, the material fatigue degradation model, and the surface degradation, unevenness in particular, are described. A comparison of the empirical PPM created in the last century used by the national road administrator to this day and the newly created PPM is presented. The comparison shows the difference in the calculated socio-economic benefits and subsequent cost–benefit analysis results. The comparison shows that the use of the old PPM may have produced false economic evaluation results that have led to poor decision making, partially explaining the unsustainable trend of road network management in our country.

Skynative – brings daylight into the depths of buildings

There are various ways of directing daylight into the interior of a building or a room. In cooperation with BASF, Bartenbach has developed a prototype of a horizontal daylight duct integrated into the suspended ceiling that efficiently transports daylight from the outside into the underexposed “core” of a building. “Skynative” is the name of the system, named after BASF spin-off Skynative® UG, which is working on market integration as well as continuous improvement of the system in an open research collaboration with Bartenbach. In this paper, the system concept development, simulation-based application studies as well as the setup of a real-scale mock-up, including results from a long-term performance monitoring at the premises at Bartenbach, are presented. First potential application projects are shown, and the system efficiency is discussed.

Enhancing BIM-BEM integration: solutions for efficient data exchange and energy performance assessment

ABSTRACT This paper explores the efficiency of exporting data from Building Information Modeling (BIM) to Building Energy Modeling (BEM) and proposes solutions to encountered problems. The study considers both detached and attached buildings, analyzing the impacts of resolution parameters, and evaluating energy performance based on BIM model. A case-study approach is employed using a residential apartment building, with data exported from Autodesk Revit and imported into DesignBuilder. The results demonstrate the significance of adjusting resolution parameters (the primary parameters that influence the energy analytical model's accuracy and processing time) for efficient data export. Exploring different values leads to improvements in resolving unclosed spaces and enhancing the geometrical model of building elements. Challenges persist in allocating material finishes to walls. By improving and integrating energy performance evaluation through enhanced accuracy and efficiency of data exchange, the findings have significant impacts on stakeholders involved in building design, construction, and operation. Additionally, this process can optimize energy consumption in buildings. Further research is needed to address remaining challenges and improve BIM to BEM systems compatibility including the development of smart mechanisms for energy model creation and resolution parameters refinement. Case studies on different building types and long-term performance monitoring are recommended. This research contributes to the efficiency of exporting data from BIM to BEM interfaces, offering insights for practitioners and guiding future research in BIM-BEM tools integration.

Performance indicators in long-term care for older people in 38 countries: a scoping review

Abstract Background A large number of performance indicators in long-term care have been developed and tested. However, the use of such indicators for regular monitoring of long-term care at regional and national level presents a number of challenges related to coordination of stakeholders, regulation and data collection capabilities. Our aim was to review the performance indicators in long-term care that are currently in use for regular monitoring by 38 OECD member states. Methods We used a scoping review approach that included a systematic search of scientific publications, review of multi-country reports and an internet search of relevant websites of the countries included. The scoping review protocol was registered before starting paper selection and web searches. Results We retrieved 12.776 papers, of which 10 were kept after selection for data extraction. Preliminary results of the review of reports and internet resources led to the retrieval of 399 performance indicators in long-term care from 24 OECD member states, while no indicators could be found for 14 member states. Performance indicators most often relate to falls, pressure ulcers, unplanned weight loss and use of restraints, which are collected by 7 or more of the 24 countries. The definitions of the indicators differ considerably between countries, as well as the definitions of long-term care and hence the settings in which these indicators are used. Conclusions Consideration of indicators often used in several countries may be of interest to decision-makers establishing or updating indicator sets in this area. There is considerable heterogeneity in the nature, definitions and settings of long-term care performance indicators used by OECD member states. These differences are a significant challenge to establish international comparability of the indicators reported. Key messages • The indicators most frequently used for regular monitoring of long-term care performance are related to falls, pressure ulcer, unplanned weight loss and use of restraints. • There is considerable heterogeneity in the nature, definitions and settings of long-term care performance indicators used in different countries, which make comparisons of results challenging.

An exploratory framework for accelerated airport pavement testing using the geotechnical centrifuge

ABSTRACT Full-scale Accelerated Pavement testing (APT) has been regarded as an essential step to bridge the gap between research and practice for pavement design because it can fully mimic a large number of heavy wheel loading on pavements. Despite being able to test pavements in an accelerated manner compared to Long-term Performance Monitoring (LTPM), conducting one full-scale APT experiment is still demanding in terms of monetary cost, space, time, etc., and the accessibility to APT facilities is only available in a few countries nowadays. In this study, an exploratory APT study with a down-scaled pavement model in a high-g environment created by geotechnical centrifuge was performed with up to half a million simulated aircraft load repetitions. Through this test, it was proved that the centrifuge APT can reproduce the full-scale airfield pavement responses, including rutting, cracking, material fatigue, etc. The transient and permanent deflection of the pavement surface, variations in stress and strain states within the pavement structure over its lifespan can be well captured for analysis. This framework of centrifuge APT provides a new methodology for pavement testing and can significantly save the current cost and time of full-scale APT.

Long-term microbiota and performance monitoring of a highly efficient propylene oxide co-production methyl tert-butyl ether production wastewater treatment plant

A wastewater treatment plant (WWTP) was constructed specifically to treat 543,900 m3 wastewater annually generated by a novel propylene oxide (PO) co-production methyl tert-butyl ether (MTBE) petroleum chemical factory in this study. The WWTP consisted of expanded anaerobic granular sludge beds (EGSBs) and aerobic activate sludge tanks (AASTs), which have been operated for 1340 days. The chemical oxygen demand (COD) and petroleum oils of the WWTP influent were 5140 ± 844 mg/L and 70.08 ± 16.57 mg/L, respectively. The overall removal efficiencies for COD petroleum oils were 94.43% ± 2.36% and 93.46% ± 5.95%, respectively. EGSBs account for 41.48% ± 10.52% of the total COD removal, while AAST contributed to 52.95% ± 10.18%. AAST played a prominent role in the removal of petroleum oils. The optimum COD volume loading rate (VLR) of EGSBs during the operation was 1.83 ± 0.10 kg COD/m3/d, whereas the average COD VLR of AAST was 0.45 ± 0.09 kg COD/m3/d. The composition of dominant microorganisms found in EGSBs and AASTs significantly enhance the performance and efficiency of the WWTP. This study underscores the potential of employing a similar approach for long-term and efficient treatment of industrial complex pollutants, while also highlighting the presence of microbiota with exceptional capability to remove petrochemical contaminants.

Degraded Ballast Stiffness Characterization Using Bender Element Field Sensor and PANDA® Penetrometer

The progressive degradation of railway ballast over time increases the degree of ballast fouling and poses significant drainability concerns leading to frequent maintenance activities. To avoid such issues, an effective and continuous characterization of the physical properties of the ballast layer is deemed necessary. This paper introduces the combined use of a bender element (BE) piezoelectric field sensor and a PANDA® dynamic cone penetrometer for periodic evaluations of ballast condition over the traffic use. To simulate various levels of ballast degradation, box tests were conducted using a dolomitic ballast material compacted in a laboratory-sized testbed with fouling indices ranging from zero to 39%. BE sensor pairs were embedded in the ballast layer to calculate the small strain modulus behavior of the ballast assessed through shear wave velocity measurements under different confinement conditions. Strength profiles of the ballast at different fouling levels were also measured using the PANDA® penetrometer. Experimental findings from both test methods indicate the existence of a dense state of ballast linked to a certain fouling index that maximized stiffness and strength characteristics of the tested ballast in dry condition. Accordingly, the potential use of BE field sensors embedded within in-service ballasted track coupled with periodic penetration testing can be a viable approach to evaluate ballast layer degradation. Various void packing conditions associated with ballast fouling levels can be linked to important ballast layer modulus and strength behavior. Further, such smart sensing of ballasted track behavior can provide long-term performance monitoring solutions for ballast cleaning and maintenance scheduling.

Scalable Analysis of Untargeted LC-HRMS Data by Means of SQL Database Archiving.

Liquid chromatography-high-resolution mass spectrometry (LC-HRMS) is widely used to detect chemicals with a broad range of physiochemical properties in complex biological samples. However, the current data analysis strategies are not sufficiently scalable because of data complexity and amplitude. In this article, we report a novel data analysis strategy for HRMS data founded on structured query language database archiving. A database called ScreenDB was populated with parsed untargeted LC-HRMS data after peak deconvolution from forensic drug screening data. The data were acquired using the same analytical method over 8 years. ScreenDB currently holds data from around 40,000 data files, including forensic cases and quality control samples that can be readily sliced and diced across data layers. Long-term monitoring of system performance, retrospective data analysis for new targets, and identification of alternative analytical targets for poorly ionized analytes are examples of ScreenDB applications. These examples demonstrate that ScreenDB makes a significant improvement to forensic services and that the concept has potential for broad applications for all large-scale biomonitoring projects that rely on untargeted LC-HRMS data.

Monitoring and assessment of a cross-passage twin tunnel long-term performance using wireless sensor network

The monitoring and assessment of ageing underground tunnels is critical to ensure their serviceability, stability, and safety as arteries for a transport network in the long term. This paper first comprehensively reviewed the long-term tunnel performance monitoring case studies, aimed at highlighting the limited field monitoring data and identifying research gaps. It was found that previous studies largely focused on the performance of single tunnel sections subject to short-term disturbances (e.g., adjacent excavation), whereas limited efforts concentrated on the long-term performance of twin tunnels, let alone those with cross passages, under the influence of deteriorations. To this end, a Wireless Sensor Network (WSN) was deployed at a critical vehicle cross passage (VCP) twin tunnel section of Dublin Port Tunnel to monitor its long-term ageing performance with time, in addition to the existing long-term water leakage and lining crack monitoring. The evolvement of lining crack and water leakage since 2010 indicated the progressive deteriorations of the monitoring section, and the deployed WSN monitoring of lining inclination demonstrated a robust sensor deployment layout and monitoring plan for (quasi) real-time monitoring for a confined underground cross passage twin tunnel network. An analytical solution was proposed to convert tunnel inclination to horizontal deformation, with the converted measurements suggesting that even more than one decade after construction, both twin tunnels are still moving horizontally towards the VCP centreline in the long term, primarily due to twin tunnel interaction. Along tunnel longitudinal direction, the closer to the VCP, the greater tunnel deformation rate is, revealing the effect of cross passage on tunnel differential longitudinal behaviour, in agreement with hypotheses and numerical results in previous studies. The field observations were believed to be attributed to the two mechanisms which are hydro-geological degradation of the surrounding ground and hydro-mechanical deterioration of the tunnel, where the correlation between tunnel deformation and deteriorations was detailed.

Blockchain + IoT sensor network to measure, evaluate and incentivize personal environmental accounting and efficient energy use in indoor spaces

Electric demand flexibility in buildings is highly dependent on occupant behavior. Evaluating and incentivizing these behaviors can provide grid-responsive support and encourage demand response (DR) participation. To achieve these goals, we developed an infrastructure for connecting Internet of Things (IoT) sensors to a distributed ledger (blockchain network) for long-term monitoring of energy and environmental performance. This study presents a novel Blockchain + IoT paradigm for the building science research community, applied in a real-world application. This Blockchain + IoT Network (BIN) uses Raspberry Pi minicomputers as platforms for connecting sensors to a blockchain network, to provide and analyze real-time indoor environmental quality (IEQ), energy, and carbon intensity data. As part of the study, we propose various metrics to evaluate the environmental footprints of building users. Novel algorithms for normalizing energy usage and carbon intensity, with consideration of a variety of related environmental factors, are executed as smart contracts on the blockchain network. All measurements and the smart contract transactions are reported and visualized on live dashboards. The use of smart contract allocates tokens based on the reward algorithms to incentivize individuals’ energy conservation, and similarly to DR pricing, can help influence occupant consumption patterns towards carbon reduction goals. We further test the smart contract’s algorithm in relation to real sensor data we have collected in two case studies: single-unit households and carbon intensity in the energy market. The combination of proposed metrics translates measured sensor data into token awards, demonstrates upper and lower limits dictated by the grid generation mix profile, and indicates that there is the potential for load shifting to minimize carbon emissions without considering the scale of consumption.

CO2-fixing steel slag on hydration characteristics of cement-based materials

In this paper, the effects of CO2-fixing steel slag powder on the hydration characteristics of cement-based materials are compared, including the early liquid phase ion concentration, hydration heat, chemically bound water and strength. After the steel slag powder is cured by CO2 form the cement kiln flue gas, the calcium-containing ore phase is transformed into calcium carbonate. Calcium carbonate has a nucleating effect, which promotes the early hydration process, increases the ionic concentration and pH value of the liquid phase. Moreover, residual bacteria also have a positive effect when using bacteria and steel slag for CO2 sequestration. The change of the steel slag powder to the liquid phase environment leads to a significant difference in the early hydration exotherm, and the hydration kinetic parameters also have a large change. Comparing with the untreated steel slag powder, the low-carbon clean cement-based materials prepared from the CO2-fixing steel slag powder have a higher degree of hydration reaction from the NG process to the I process and from the I process to the D process during hydration. It shows that the steel slag powder after CO2 fixation is beneficial to the early hydration process. The monitoring of long-term performance found that the low-carbon auxiliary cementitious material prepared by the synergistic CO2 fixation of bacteria and steel slag powder has greater application potential in cement-based materials.

Degradation and reliability analysis of photovoltaic modules after operating for 12 years: A case study with comparisons

The long-term performance monitoring and characterization of field-exposed solar photovoltaic (PV) modules are essential for efficient power generation. This paper is an attempt at performance evaluation of the amorphous silicon (a-si), Heterojunction Intrinsic Thin layer (HIT), and Multi-Crystalline (mc-si) technologies after twelve years of outdoor exposure in the composite climate of India. Characterization techniques such as Visual Inspection, Infra-Red (IR) Thermography, Electroluminescence (EL) Imagining, and Electrical characterization have been carried out. I–V measurements, power losses, current degradation, and voltage degradation calculations are carried out. The percentage of electrical decline is 8.61%, 2.73%, and 29.08%, for Isc, Voc, and PMP respectively in a-si solar modules. For HIT modules 1.97%, 0.68%, and 0.48% for Isc, Voc, and VMP respectively. Finally, for the mc-si PV modules, these are 3.76%, 0.5%, and 1.44% for Isc, Voc, and PMP respectively over 12 years. The average degradation rates are found to be 1.24%/year, 0.14%/year, and 1.50%/year for a-si, HIT, and mc-si modules respectively. The EL imagining of the a-si modules shows the localized shunt over the surface of the modules as well as disconnected cell interconnects whereas no such defects are over the m-ci and HIT modules.

Clinical enrollment assay to detect preexisting neutralizing antibodies to AAV6 with demonstrated transgene expression in gene therapy trials

Recombinant adeno-associated virus (AAV) vectors are the leading platform for gene delivery for a variety of clinical applications. Patients with preexisting antibodies to AAV are currently excluded from most AAV gene therapy trials to avoid vector neutralization and ensure response to therapy. Anti-AAV neutralizing antibodies (NAbs) are typically assessed by in vitro cell-based transduction inhibition (TI) assays. However, clinical relevance of the determined enrollment cutoff and the inherent variability of a cell-based assay present challenges for use as an enrollment screening test. Here, we describe an enrollment cutoff that was clinically validated and strategies to overcome assay challenges to enable long-term stable performance. A validated anti-AAV6 cell-based TI assay was used to support clinical enrollment across multiple investigational gene therapies and to evaluate AAV6 seroprevalence in healthy and disease populations. The clinical enrollment cutoff was determined statistically using samples collected from healthy donors, applying a 0.1% false error rate with the inclusion of a minimum significant ratio (MSR) metric and in consideration of results from in vivo mouse passive transfer studies. Our strategy for long-term monitoring and control of assay performance employed plate quality control samples flanking the predefined cutoff. An approach using donor samples was implemented to bridge different lots of critical reagents without the need to redefine the cutoff.

A full-section asphalt concrete waterproof sealing structure for the high-speed railway subgrade

PurposeThis study aims to investigate the service performances of a new full-section asphalt concrete waterproof sealing structure (FSACWSS) for the high-speed railway subgrade through on-site tracking, monitoring and post-construction investigation.Design/methodology/approachBased on the working state of the waterproof sealing structure, the main functional characteristics were analyzed, and a kind of roller-compacted high elastic modulus asphalt concrete (HEMAC) was designed and evaluated by several groups of laboratory tests. It is applied to an engineering test section, and the long-term performance monitoring and subgrade dynamic performance testing system were installed to track and monitor working performances of the test section and the adjacent contrast section with fiber-reinforced concrete.FindingsResults show that both the dynamic performance of the track structure and the subgrade in the test section meet the requirements of the specification limits. The water content in the subgrade of the test section is maintained at 8–18%, which is less affected by the weather. However, the water content in the subgrade bed of the contrast section is 10–35%, which fluctuates significantly with the weather. The heat absorption effect of asphalt concrete in the test section makes the temperature of the subgrade at the shoulder larger than that in the contrastive section. The monitoring value of the subgrade vertical deformation in the test section is slightly larger than that in the contrastive section, but all of them meet the limit requirements. The asphalt concrete in the test section is in good contact with the base, and there are no diseases such as looseness or spalling. Only a number of cracks are found at the joints of the base plates. However, there are more longitudinal and lateral cracks in the contrastive section, which seriously affects the waterproof and sealing effects. Besides, the asphalt concrete is easier to repair, featuring good maintainability.Originality/valueThis research can provide a basis for popularization and application of the asphalt concrete waterproof sealing structure in high-speed railways.

Long-term friction performance monitoring of sliding layer in China railway track system Ⅱ slab track on bridge superstructure

The sliding layer is an important component of the China Railway Track System (CRTS) Ⅱ slab track on bridges, and its friction performance has a significant influence on the intensity of track–bridge interaction (TBI). However, the friction performance deterioration of this sliding layer under actual repeated abrasion and harsh environmental conditions is difficult to grasp since structural health monitoring implementation into in-service high-speed railway tracks is extremely hard to be permitted and only limited valuable monitoring datasets are available at present. In this study, the friction performance degradation of the sliding layer was therefore investigated using long-term monitoring data from a multi-span simply supported box girder bridge. First, the friction-induced strain in the base plate was decoupled using the monitored strain at the fixing point and mid-span based on mechanical properties of TBI. Then, structural health monitoring and finite element analysis both indicated an approximately linear relationship between the decoupled friction-induced strain and the temperature of the investigated bridge under certain circumstances. Furthermore, the correspondence between the slope of this linear relationship and the friction coefficient was modelled. Finally, the friction coefficients of the sliding layers on target spans were identified using 4 years of monitoring data and the established correspondence model to analyse the statistical characteristics and degradation performance of the layers. This investigation of the friction performance degradation of the sliding layer in the CRTS II slab track system provides guidance for future maintenance and replacement decision making.

Long-Term Monitoring of Training Load, Force-Velocity Profile, and Performance in Elite Weightlifters: A Case Series With Two Male Olympic Athletes

Sandau, I and Granacher, U. Long-term monitoring of training load, force-velocity profile, and performance in elite weightlifters: a case series with two male Olympic athletes. J Strength Cond Res 36(12): 3446-3455, 2022-The aim of this case series approach was to analyze weekly changes in force-velocity relationship (FvR) parameters (v̅0, F̅0, P̅max) and theoretical snatch performance (snatchth) assessed through a specific snatch pull test in preparation of the European and World Championships in 2 male elite weightlifters. A second aim was to examine associations of training load (volume, volume load, average load), barbell FvR-parameters, and snatchth over a period of 2 macrocycles in preparation of the same competitions. FvR-parameters, snatchth, training load data, and body mass were assessed weekly over 40 weeks. Using the smallest real difference approach, significant (p ≤ 0.05) decreases in v̅0 and increases in F̅0, P̅max, and snatchth were found within macrocycles. However, the large significant loss in body mass (≈11%) in athlete 1 during macrocycle 2 represents most likely a main factor for diminished P̅max, and snatchth in macrocycle 2. Based on cross-correlation analyses, barbell FvR-parameters and snatchth were significantly (p ≤ 0.05) associated with maximal strength, muscle power, and speed training load variables. Moderate correlations (0.31-0.47) were found between training load and P̅max and snatchth in athlete 2. It can be concluded that the applied training loads elicits improvements in P̅max and snatchth because the athlete approached the main competitions. However, because of the large loss in body mass, the relations between training load and barbell FvR-parameters and snatchth were less clear in athlete 1. It seems that a loss in body mass as a result of a change in bodyweight category mitigates P̅max development during the macrocycle and hindered to reach peak snatchth at the main competitions.

Long-Term Techno-Economic Performance Monitoring to Promote Built Environment Decarbonisation and Digital Transformation—A Case Study

Buildings’ long-term techno-economic performance monitoring is critical for benchmarking in order to reduce costs and environmental impact while providing adequate services. Reliable building stock performance data provide a fundamental knowledge foundation for evidence-based energy efficiency interventions and decarbonisation strategies. Simply put, an adequate understanding of building performance is required to reduce energy consumption, as well as associated costs and emissions. In this framework, Variable-base degree-days-based methods have been widely used for weather normalisation of energy statistics and energy monitoring for Measurement and Verification (M & V) purposes. The base temperature used to calculate degree-days is determined by building thermal characteristics, operation strategies, and occupant behaviour, and thus varies from building to building. In this paper, we develop a variable-base degrees days regression model, typically used for energy monitoring and M & V, using a “proxy” variable, the cost of energy services. The study’s goal is to assess the applicability of this type of model as a screening tool to analyse the impact of efficiency measures, as well as to understand the evolution of performance over time, and we test it on nine public schools in the Northern Italian city of Seregno. While not as accurate as M & V techniques, this regression-based approach can be a low-cost tool for tracking performance over time using cost data typically available in digital format and can work reasonably well with limited resolution, such as monthly data. The modelling methodology is simple, scalable and can be automated further, contributing to long-term techno-economic performance monitoring of building stock in the context of incremental built environment digitalization.

상업 운항 중인 대형 컨테이너선의 항차 중 속력 시운전을 통한 선속-동력 특성 연구 Part I

This paper presents the analysis of the speed-power performance in the real sea using a large container vessel data provided as a test bed from a shipping company. To perform a speed trial of the vessel during a commercial voyage, the on-board measuring device and various operation data acquisition systems were mounted on the vessel for long-term performance monitoring and the voyage operated under the container loading condition close to the design draft was adopted. The content of this paper consists of Part I and Part II. Part I, such as this paper, contains the speed trial method and analysis results of the operating vessel. Part II contains the analysis of the speed-power characteristics change over time and before and after hull cleaning using operation data measured from the voyage operated under a condition similar to the speed trial.

High Friction Surface Treatment Deterioration Analysis and Characteristics Study

High friction surface treatment (HFST) is used to improve friction on curved roadways, especially on curves that have a history of wet pavement crashes. Observations on the long-term performance monitoring of HFST sections at the National Center for Asphalt Technology (NCAT) Test Track showed friction (skid number, SN) dropped significantly at the end of service life of HFST, creating unsafe driving conditions. There is no clear, observed friction deterioration trend to predict the friction drop when using friction performance measures like SN. Therefore, there is an urgent need to explore and develop supplementary HFST safety performance measures (such as aggregate loss) that can correlate to friction deterioration and provide predictable, cost-effective, and easily measurable results. The objectives of this paper are to (i) analyze the correlation between HFST aggregate loss percentage area and friction value using a dynamic friction tester (DFT), and (ii) study the characteristics of HFST deterioration associated with aggregate loss, at the NCAT Test Track and at selected HFST curve sites in Georgia (using 2D imaging and high-resolution 3D laser scanning). Results show a strong correlation between HFST aggregate loss percentage area and DFT friction coefficient. Where friction measurement is used as the primary safety performance measure, it is recommended that HFST aggregate loss be used as a supplementary performance measure for monitoring the HFST safety performance deterioration. Aggregate loss can be easily identified by characteristics such as color and texture change. Preliminary texture analyses of 3D HFST surface profiles show lower mean profile depth (MPD) and ridge-to-valley depth (RVD) texture indicators can also identify loss of aggregate spots on HFST surface.

MONITORING PERFORMANCE OF LATERITE BASE TRIAL SECTION: A CASE OF ADDIS ABABA, ETHIOPIA

This paper is aimed to present an overview of the provision of a demonstration/research trials with particular reference to pavement performance of a laterite base under a double bituminous surface treatment (DBST) as part of a long-term pavement performance (LTPP) monitoring in Ethiopia. The research components were aimed at increasing the use of locally available materials and solving specific problems related to the performance of some roads constructed with thin asphalt seals. In Ethiopia, most roads are built using crushed rock for road base. The project aim was to demonstrate that whether laterite can be used for base course, assess and evaluate the effect of sealed and unsealed shoulder in cut and fill sections. Out of the various field data measurements carried out in each monitoring period (wet and dry season) the paper reviews the in-situ dynamic cone penetrometer (DCP) test results and visual condition assessment observations. It is demonstrated that for such low volume roads laterite base trial sections are performing well, however DCP test results in these sections reveals that the crushed base control sections perform slightly better than the laterite base trial sections and the sections in cut are stronger than in fill while the shoulder sealing doesn’t provide consistent effect on the layer strengths.