Deflectometer Research Articles

Field performance of bitumen emulsion Cold Central Plant Recycling (CCPR) mixture with same day and delayed overlay compared with traditional rehabilitation procedures

Cold Recycled Mixtures (CRM) offer many benefits, including cost-effectiveness and sustainability. Large existing Reclaimed Asphalt Pavement (RAP) stockpiles that represent an environmental and storage challenge can be used for bitumen emulsion Cold Central Plant Recycling (CCPR). A pavement rehabilitation demonstration project using Cold Recycled Mixture with Bitumen Emulsion (CRM-E) as binder course with 100% RAP was carried out on August 25, 2020. The project was divided into three sections to evaluate the mill and pave strategy using CRM-E as an alternative to traditional Hot Mixture Asphalt (HMA). The wearing course was the same asphalt concrete for the three sections. The difference between Section 1 and 2 that used CRM-E was to either pave the asphalt concrete overlay on the same day or to delay its application for 3 days to give additional time for the CRM-E to cure. Section 3 had no CCPR and consisted of two HMA layers. The field performance of the rehabilitated sections was monitored in 4 phases after 14 days, 3 months, 6 months and 12 months. The performance of the sections was assessed based on Falling Weight Deflectometer (FWD), field rutting measurements and cracking distress surveys. Cores were also taken over time to compare the CRM-E and HMA binder course properties in terms of resilient modulus, dynamic creep, indirect tensile strength and tensile strength ratio. The research showed that CRM-E and HMA performance was similar in terms of FWD deflections, field rutting, in situ cracking, and moisture resistance of the field cores. CRM-E showed superior performance in terms of resilient modulus and dynamic creep compared with asphalt concrete binder course based on testing of field cores taken after 6 and 12 months. The research showed that same day CRM-E HMA overlay is a viable construction option.

Study on the Influence of Excavation Unloading on Pile Depth in Sandy Soil

With the development of urban construction, uplift pile has been widely used in underground structure bearing buoyancy. The pile is buried deep underground, and the foundation pit is excavated on the pile foundation, the stress redistribution of the soil after the foundation pit excavation will reduce the lateral stress of the pile at the bottom of the pit, resulting in the reduction of friction resistance, but this effect is limited to a certain depth at the bottom of the foundation pit. Referring to the unloading influence depth corresponding to the vertical unloading coefficient in the spring back calculation of foundation pit and introducing the unloading influence depth corresponding to the horizontal unloading coefficient, it is deduced that the relationship between the horizontal unloading coefficient and the vertical unloading coefficient is based on the friction angle. Based on the bearing capacity control and numerical simulation, it is determined that the corresponding depth when the horizontal unloading coefficient is 0.95 is the unloading influence depth. The depth to width ratio of excavation has a great influence on unloading influence depth, and the internal friction angle of soil has little influence on unloading influence depth, while the influences of pile diameter and pile-soil friction coefficient can be ignored. The formula of unloading influence depth is derived in this paper. Comparing the unloading influence depth of sand and soft soil, the unloading influence depth of sand is greater than that of soft soil.

Selection of suitable backcalculation technique and prediction of laboratory resilient modulus from NDT devices

ABSTRACT This study aims to analyse the backcalculated cohesive subgrade moduli using various backcalculation approaches. A series of in situ and laboratory investigations have been carried out on 190 test locations from 30 pavement sections of cohesive soils using Falling Weight Deflectometer (FWD), Light Weight Deflectometer (LWD), and Repeated Load Triaxial to determine backcalculated resilient moduli (MR_back), composite resilient moduli (MR_comp), and laboratory resilient modulus (MR_lab). The comparative analysis was performed for MR_back by LWD (MR_back_LWD), MR_comp by LWD on subgrade (MR_comp_LWD), and MR_back by FWD (MR_back_FWD) with MR_lab values to assess the level of agreement. MR_back_FWD and MR_back_LWD values of different soils by using Artificial Neural Network and Support Vector Machine techniques have shown the mean percentage variation (1.16–59.63%), correlation in terms of R2 value (0.628–0.824), and RMSE value (0.51–20.49%) with MR_lab values. In contrast, MR_comp_LWD values have shown good agreement with MR_lab values among MR_back_LWD and MR_comp_LWD. This study also suggested adjustment factors (0.308–0.974) for predicting MR_lab values from MR_back_FWD and MR_back_LWD for cohesive soils. Thus, this study recommends an appropriate backcalculation technique and suggests adjustment factors to the cohesive type of soils for realistic prediction of resilient characteristics of subgrade.

Deflection Prediction of Rehabilitation Asphalt Pavements through Deep Forest

The deep forest is a powerful deep-learning algorithm that has been applied in certain fields. In this study, a deep forest (DF) model was developed to predict the central deflection measured by a falling weight deflectometer (FWD). In total, 11,075 samples containing information related to pavement structure, traffic conditions, and weather conditions were extracted from the LTPP dataset. The performance of the DF model with custom backend settings was compared with that of models random forest (RF), multilayer perceptron (MLP), and DF built on the sklearn backend. All four deep-learning algorithms could identify the complex relationship between central deflection and relevant feature variables with high accuracy and stability. The learning and generalization abilities of DF was stronger than those of MLP and RF. The predictive performance and computation time of DF (custom) were better than those of DF (sklearn), indicating that the custom model was superior to the highly encapsulated model with sklearn as the backend. Feature importance analysis indicated that the drop load of FWD was the key factor influencing deflection. In addition, structural number, annual precipitation, and annual kilo equivalent standard axle load (kESAL) are very important features related with deflection. The feature importance of rehabilitation improvement thickness was less than the drop load, climatic factors, kESAL, structural number, and layer thickness.

Beak Microstructure Estimates of the Age, Growth, and Population Structure of Purpleback Flying Squid (Sthenoteuthis oualaniensis) in the Xisha Islands Waters of the South China Sea

This study aimed to explore the feasibility of using an upper beak microstructure to estimate the age of purpleback flying squid (Sthenoteuthis oualaniensis). From these microstructures, the age and growth of squid caught from January to March and May to August in 2018, 2019, and 2020 in the waters surrounding the Xisha Islands in the South China Sea were determined. We found three typical growth zones (the hood region, crest region, and axis), abnormal increments (checks), and erosion in the beak examination. The average dorsal mantle length (ML) of males and females was 112.13 (±15.23 mm) and 119.67 mm (±24.50 mm), respectively, and no squid were older than 10 months. The peak hatching dates, according to back calculations, were from October to January of the next year. All sampled squid belonged to the autumn/winter cohort. Significant sex differences were found in the relationship between ML and age in squid with similar growth patterns. Exponential models best described the relationships of ML with age and body weight (BW) for both sexes. However, a linear model best described the relationship between age and upper rostrum length (URL). The maximum absolute daily growth rates (AGR) of BW were reached during days 240–270 for both sexes. The maximum AGRs in ML were reached during days 180–210 and 240–270 for males and females, respectively. The period of 120–150 days (4–5 months) was considered the sub-adult stage of S. oualaniensis in the Xisha Islands waters of the South China Sea. This study confirmed that the beak microstructure provides good age estimates for purpleback flying squid (S. oualaniensis).

Experimental investigation on the damping characteristics in dry and saturated sands

An experimental study of the behavior of sandy soils having different densities was conducted under the action of a single impulsive load. Dry silica sands of different densities and saturated sand were tested. Different falling masses from different heights were conducted using the falling weight deflectometer to provide the single pulse energy. Variation of damping with different parameters was examined, these are; footing embedment, depth to diameter ratios, diameter of the impact plate, the applied energy and soil density (dense, medium, and loose) in addition to moisture content (dry or saturated sands). The variation of soil density leads to increase the damping ratio increases by about 20-80% when the soil density is varied from loose to dense.

Resilient modulus estimation using in-situ modulus detector: performance and factors

ABSTRACT The resilient modulus of subgrade should be estimated for pavement designs that undergo repetitive loading from vehicular movement. In this study, an in-situ modulus detector (IMD) with flat, wedge, and cone tips is employed to estimate the resilient modulus. The specimens with three different levels of water content are compacted, and the dynamic responses for two hammer drop heights are analysed. For all specimens, elastic waves are acquired to estimate the shear modulus and Poisson’s ratio using bender and piezo-disk elements. The resilient modulus estimated from the IMD is compared with the lightweight deflectometer (LWD) modulus. The experimental results show a stronger relationship between the flat and wedge tips than between the cone and wedge tips. Furthermore, higher drop heights result in strong relationships between the resilient, shear, and LWD moduli. This study proposes an intrinsic design and verification of an IMD for reliable resilient modulus estimation in pavement design.

Fish and Zooplankton Community Responses to the Cessation of Long-Term Invasive Eurasian Watermilfoil (Myriophyllum spicatum) Chemical Treatments in a North-Temperate, USA Lake

2,4-Dichlorophenoxyacetic acid (2,4-D) is commonly used to control invasive aquatic macrophytes, including Eurasian watermilfoil (Myriophyllum spicatum) (EWM). Potential influences of 2,4-D on non-target organisms are poorly understood; however, research has suggested the possibility of lethal effects on certain fish species. Lake Ellwood, Wisconsin was treated with 2,4-D to control EWM annually during 2003–2012. Fish surveys following treatment revealed natural recruitment failures of several regionally thriving species, including largemouth bass (Micropterus salmoides) and bluegill (Lepomis macrochirus). We hypothesized that these species had been negatively influenced by the chemical treatments. We monitored the post-chemical treatment fish community and aquatic ecosystem for responses during 2013–2019. Similar data were collected from Cosgrove (EWM absent) and Seidel lakes (EWM present, no chemical treatment) as reference systems. Limnological and submersed aquatic vegetation conditions did not change on Lake Ellwood post-chemical treatment. Total zooplankton density increased immediately post-chemical treatment on Lake Ellwood and then stabilized, whereas total zooplankton density did not change on the reference lakes over time. Analyses indicated immediate increases in recruitment post-chemical treatment for largemouth bass, smallmouth bass (Micropterus dolomieu), bluegill, and yellow perch (Perca flavescens). Back calculation of year class strength confirmed failures occurred during treatment for northern pike (Esox lucius), largemouth bass, bluegill, and black crappie (Pomoxis nigromaculatus). Our results provide evidence to suggest long-term 2,4-D treatments may negatively influence fish through lethal and sublethal mechanisms. Thus, there remains a critical need for directed research on whole-lake herbicide treatment side-effects.

Analysis of the influence of tropical soil classification methods on railway subgrades according to repeated load triaxial (RLT) and light weight deflectometer (LWD) tests

Recently, non-destructive in-situ tests have emerged that can predict the resilient modulus (MR) of materials that make up railway sidewalk layers in an agile and low-cost manner. These are in contrast to laboratory tests that require more infrastructure and are more time-consuming to perform. However, few studies have been directed to the resilient behavior compared to in-situ and laboratory tests for soils classified as tropical. This paper aims to determine the relationship between the estimated modulus of elasticity (ELWD) and the estimated resilient modulus (MR) from the repeated load triaxial test (RLT) for use in tropical soil railway subsoils. The samples of subgrade soils belong to a railway stretch in Brazil, present in the states of São Paulo-SP and Minas Gerais-MG, which has large circulation of minerals and commodities. The soils are classified as lateritic and non-lateritic according to the Brazilian Miniature, Compacted, Tropical (MCT) methodology, in addition to grain size, compaction, LWD and RLT tests. It is noted that the modulus of elasticity (ELWD) tends to decrease according to the increase in strain obtained in LWD. For soils classified as lateritic, as the soil moisture increases the ratio between the moduli obtained by RLT and LWD tend to increase. However, non-lateritic soils have the opposite performance, i.e., the ratio between the modulus of the tests decreases with increasing moisture. In this study, the LWD test is a possible viable alternative with good accuracy and effectiveness for geotechnical investigations in tropical soils.

Surface layer modulus prediction of asphalt pavement based on LTPP database and machine learning for Mechanical-Empirical rehabilitation design applications

Evaluating the modulus of the existing asphalt concrete (AC) layer is a critical procedure in Mechanical-Empirical (ME) rehabilitation analysis. Generally, the modulus could be back-calculated by the Falling Weight Deflectometer (FWD) test. However, the raw FWD data of each pavement section is not always readily prepared for local highway agencies. To address this issue, the main objective of this study is to establish a reliable model by machine learning (ML) methods to predict AC layer modulus for the existing flexible pavement with data readily available from the local pavement management system, which could be an auxiliary tool for network-level sections with no FWD tests. The long-term pavement performance (LTPP) database was used to collect the original data for model training and testing, including pavement structures, service age, climate records, and pavement distresses. After preliminary data processing, matrix correlation analysis, and feature selection, the prepared dataset (total data points = 6477) with 14 predictors was fed into three regression models, including Ordinary Least-Squares regression (OLS), Random Forest regression (RF), and Gradient Boosting regression Method (GBM). The related key hyperparameters were optimized by grid search and 5-folds cross-validation. By comparison, the GBM model was finally selected due to its considerably higher prediction accuracy (R2 = 0.7921) than RF model (R2 = 0.7525) and OLS model (R2 = 0.4371) in the test set. According to the variable importance given by GBM model, surface temperature and AC layer thickness are more dominant variables in modulus estimation. In addition, a case study with predicted AC layer moduli in ME rehabilitation design was provided to verify the model application. In summary, the trained GBM model can be utilized to predict AC layer modulus for pavement evaluation and then ME rehabilitation when FWD data is not available.

Structural evaluation of flexible pavements using impact deflectometer

For this study, an analysis was carried out on eight (8) roads of the fifth (5) town of Usme in the city of Bogotá, which were built with conventional pavement structures (granular bases and granular sub-bases) and others that were intervened with recycled materials - RAP. Lately, it has been chosen to carry out techniques for high-performance tests, known as non-destructive tests, Among these tests, the use of the FWD impact deflectometer stands out, whose function is to analyze the structural condition of the pavements by interpreting the deflections produced under dynamic loads that simulate the effect of traffic and then perform retro calculations that are evaluated at through indicators to obtain modules and structural numbers.
 Keywords: RAP, Back calculation, Resilient modulus, Deflectometry, Pavement.

Structural Evaluation by FWD In Flexible Pavement

Pavement performance evaluation an prediction are of great importance to facilitate pavement management system. Pavement evaluations are conducted to determine functional and structural conditions of a pavement section either for purposes of routine monitoring or planned corrective action. The Falling Weight Deflectometer is a device that is used to evaluate pavement and pavement layer stiffness. It is a trailer-mounted device that operates by dropping a weight on to the pavement and measuring the resulting pavement deflections. Various computations may be performed on the deflection data to evaluate the pavement and the stiffness of it and its constituent layers. During testing, a FWD subjects the pavement surface to a load pulse which simulates the load produced by a rolling vehicle wheel. The load pulse is produced by dropping a large weight onto a "buffer" which shapes the pulse, and then transmitted to the pavement through a circular load plate. Data are acquired from various sensors for use in post-test analysis of pavement properties. Data collected from FWD can be used for determination of structural capacity of in-service pavements for analytical analysis of pavement performance, predicting layer moduli for pavement component layers, remaining life of pavements and in deciding strengthening and rehabilitation measures to be adopted for meeting the requirements. Analyses of data are being carried out using standard software as supplied by the manufacturer. Information such as load, layer types and thicknesses, range of moduli and Poisson’s ratio etc. for different layer materials would also be needed for FWD deflection data analysis. While carrying out analyses of data, it assumes material to be homogeneous, isotropic, linear elastic, weightless and semi-infinite. This report contains evaluation on flexible pavement by FWD and according to resulting data, design of overlay will be done accordingly.

Long-Term Performance of Flexible Pavements Constructed on Recycled Base Layers

There has been an increased interest in using reclaimed asphalt pavement (RAP) aggregates as a base course in Wisconsin for the offered economic and environmental benefits. Laboratory studies showed that RAP can have resilient modulus values higher than typical natural aggregates, and can also have higher durability, especially in freeze–thaw cycles. However, it is also recognized that RAP exhibits temperature sensitivity and larger permanent deformations than natural aggregates. How these characteristics manifest themselves in the northern U.S. climates can only be assessed by long-term observation of field performance. Wisconsin Department of Transportation (WisDOT) has been using RAP as a base course for over 30 years. The qualitative assessment of WisDOT roads constructed with RAP showed they are performing adequately. However, this impression has not yet been verified quantitatively. This paper presents a quantitative assessment and comparisons for field performance of pavement test sections constructed with RAP and natural crushed aggregate (CA) base course layers in Wisconsin. The performance was evaluated using pavement distress surveys of roadways containing RAP and CA, falling weight deflectometer (FWD), dynamic cone penetrometer (DCP) tests, and analysis of WisDOT’s available data. Based on the field evaluation, the performance of the hot mix asphalt (HMA) pavements with RAP was found adequate and comparable to those with CA base course layers. A recommendation was given that WisDOT shall continue the practice of using RAP in base course layers of HMA pavements, given proper quality checks for materials, and proper quality control/quality assurance measures being applied during construction.

A road modulus test method based on rigid spherical indentation

Currently, the modulus test method such as falling weight deflectometer has an inevitable problem of stress concentration, which may lead to a negative impact on the results. This paper attempted to apply the spherical indentation test equipment into road detection to solve this problem. Firstly, by following the displacement boundary conditions, a general expression of modulus, force, and displacement under the semi-infinite system was established. Compared with the Sneddon’s formula (a classic formula in materials industry), this expression was consistent with it under the small deformation situations, which verified the rationality of this method. Moreover, this expression can also be utilized in the larger deformation situations, which was more in line with the pavement environment. Then, by further improving the method, this paper established the method of calculating the structure modulus of new pavement layers. Finally, a specific test method for modulus detection based on the spherical indentation was proposed.

Ten Years of Traffic Speed Deflectometer Research in the United States: A Review

This paper summarizes the research efforts into and applications of the traffic speed deflectometer (TSD) that have occurred over the last 10 years in the United States (U.S.). These are divided into three main topics which are: (1) data analysis methods including data processing, calculation of indices and structural parameters, and temperature correction; (2) evaluation efforts of TSD including repeatability and comparison with the falling weight deflectometer (FWD); and (3) applications of TSD with a focus on flexible pavement management applications, although some efforts on rigid and composite pavements are mentioned. The data analysis methods reviewed are data averaging length and reporting interval, and how deflections are calculated from the measured deflection slopes. For the calculation of indices and structural parameters the following are reviewed: deflection indices that have been proposed, the effective structural number ( SNeff), and backcalculation of layer moduli. Efforts to evaluate TSD precision (or measurement standard error) are discussed. Then, some comparisons of short-term (time frame of 1 day) and long-term (time frame of 1 year) repeatability of TSD are presented. Compared with FWD, TSD and FWD generally have good correlation, although the measurement principles of the two devices are slightly different. The focus is on network-level applications of TSD, and, more specifically, efforts to include TSD measurements in the pavement management system, especially for flexible pavements applications.

Development and validation of a temperature correction model for FWD backcalculated moduli

ABSTRACT A temperature correction model for Falling Weight Deflectometer (FWD) backcalculated dynamic modulus was developed and validated in this study. FWD test was conducted to determine the field dynamic modulus, while the indirect tensile (IDT) dynamic modulus test was used to measure laboratory dynamic modulus. A temperature correction model was developed considering the effect of FWD loading frequency and pavement temperature. It was validated using field FWD data obtained from 26 Westrack pavement sections and Korean national highways’ long-term pavement performance database. Also, the correction factor was compared with similar existing models using FWD testing in the field. It was observed from study results that the temperature correction model is capable of predicting the dynamic modulus accurately.

Comparison of Unbound Granular Materials’ Resilient Moduli Determined by Cyclic Triaxial Test and Innovative FWD Device

In addition to the conventional laboratory tests of input materials and construction mixtures, the technically correct design of pavement structure involves more frequent functional tests of the input materials and mixtures. Our study summarizes findings from a long-term monitoring of pavement on selected road sections with lower traffic intensity. The research involved the comparison of resilient moduli as a design parameter of unbound pavement base layers’ unbound granular materials (UGMs), determined in a laboratory by a test device for a cyclical triaxial test and in situ by impact load test using a falling weight deflectometer (FWD). In particular, the resilient moduli determined in the laboratory by a cyclic triaxial test (Mr,CTT) were compared with the real values of resilient moduli measured by FWD (Mr,FWD). A new, unique, and innovative FWD device was used to determine the Mr,FWD of the UGMs. The innovation lay in the dual-axis deflection measurement—measurement performed not just in the axis parallel to the road, but also in the axis in the transversal direction. It was found that, especially on roads with lower traffic load, such dual-axis (spatial) determination of Mr,FWD moduli was of great importance because it often allowed the identification of local pavement sections with low bearing capacities, especially at the edges, which have a significantly lower value of Mr,FWD.

Asphalt Elasticity Modulus Comparison Using Modified Laboratory LWD Against UMMATA Method

Highway consultants need pavement structure strength to examine and design. With advances in computer, sensor, and microelectronic technologies, the light weight deflectometer (LWD) can measure granular and asphalt layers. This portable, easy-to-use tool is suggested. This article was designed to improve LWD Pusjatan's accuracy and distinguish it from other testing methods. This study compares the LWD Pusjatan and UMMATA (Universal Material Testing Apparatus) methods for measuring modulus of elasticity on different materials. Boussinesq elastic theory is used to compute the modulus of most LWDs. In a semi-elastic environment, modulus is the connection between pressure and displacement in a rigid or flexible basis. The deflection value is derived from the process of vibrations caused by a load delivered from a given height onto a test item, with the wave/vibration collected by an acceleration measuring instrument, such as a geophone or accelerometer. The modulus of elasticity provided by the AUDL (Laboratory Deflection Test Equipment) method is less than that produced by the UMMATA method. According to the test results, the average value of AC Base material is 7.52% less than that of AC Base. The average value of AC BC material is just over 0.3%. These results indicate that more testing is necessary when using the AUDL methodology to detect correlations that might serve as a basis for comparison. Thus, the AUDL test method may be used as a nondestructive testing technique. This kind of non-destructive technique should be used frequently so that simulations of field circumstances are more accurate. Doi: 10.28991/CEJ-2022-08-06-012 Full Text: PDF

Airfield Asphalt Overlay Design for Non-conventional Pavement Structures: A Case Study of Airport in Indonesia

Airfield pavements begin a gradual deterioration from several sources, including traffic load and environmental conditions. To achieve its intended design life, routine maintenance, repair, and rehabilitation should be performed. There are considerable research and studies conducted on the design and practice of pavements rehabilitation/overlay for typical airfield pavements. However, most of the existing guidelines and studies are only suitable for pavements with conventional structures. There has been no detailed investigation into the practice of airfield asphalt overlay for non-conventional pavement structures, such as chicken claw /Cakar Ayam pavement system and nailed-slab system. In the present article, challenges and issues for airfield asphalt overlay design for non-conventional pavement structures were examined based on an actual runway rehabilitation project in one of the major airports in Indonesia in 2015. The overlay design procedure, the evaluation of the existing pavement condition, including visual surveys and deflection tests, and the pre-overlay treatments were also discussed. In addition, a finite element (FE) simulation to model the non-conventional pavement structure was developed to calculate the required overlay thickness. The result showed that, during the overlay design of non-conventional pavement structure, data from falling weight deflectometer (FWD) could not be directly used to estimate the back-calculated layers moduli because of the difference in the geometric features of the pavement structure. Moreover, the FE model can be a robust tool to simulate the complex three-dimensional geometric features of a non-conventional pavement and important loading conditions, such as interface shear bond of overlay, that are usually not available in other tools, such as FAARFIELD. Finally, this study showed that the additional asphalt overlay could reduce the fatigue stress at the bottom of the existing slab and vertical stress at the top of the subgrade, resulting in overall smaller stress levels

NATIONAL ROAD PRESERVATION BASED ON IRMS METHOD (A CASE STUDY IN JAPURA – PEMATANG REBA IN RIAU PROVINCE)

Japura Airport is one of the nodes of transportation that owned by Inderagiri Hulu (Inhu) Regency. The airport is located 14 km from the Pematang Reba. Pematang Reba is public administration office complex in Inhu Regency. This airport has flights within the province and even flights between provinces adjacent to Riau Province. The road that separates of these two cities is considered as the economic lifeblood of Inhu Regency to Riau Province. In addition, this road has fungtion not only to connect two important locations in Inhu Regency but also as only road access from Riau Province to Jambi Province. Because of the importance of this road, the condition of this road must be always maintained. Through this study, an analysis of the Remaining Structural Life (RSL) of the pavement was carried out to determine the most appropriate recommendations for road preservation work. The IRMS method is the method which used in calculating the remaining structural life (RSL) of the flexible pavement. The data requairement are deflection data from the Falling Weight Deflectometer (FWD), road geometric condition data and Average Daily Traffic (ADT). Through calculations, it was found that the apropriate flexible pavement preservation programs for Jalan Japura to Pematang Reba were divided into 3 types. Firstly, Overlays program are needed for STA 3+ 393 to STA 7+712, STA 8+509 to STA 15+70 and STA 16+510 to 16+819. Secondly, segment from STA 7+930 to STA 8+ 312 needs Reconstruction. Thirdly, STA 15+922 to STA 16+303 needs routine maintenance.