Distress Modes Research Articles

Temperature Effects on Traffic Load-Induced Accumulating Strains in Flexible Pavement Structures

AbstractRutting is a major distress mode in flexible pavements, results from the repetitive loading caused by traffic movement. Pavement deformation consists of both recoverable (elastic) and unrecoverable (plastic) components. The continuous movement of vehicles contributes to the overall deformation in the flexible pavement system, involving all pavement components. In regions with hot climates or in the hot summer season, rutting tends to be more prominent due to the substantial reduction in the viscosity of the asphalt binder. This decrease in viscosity, which is inversely linked to rutting, occurs as temperatures rise, leading to a heightened susceptibility of the Hot Mix Asphalt (HMA) blend to rut formation. However, according to studies, a significant amount of permanent deformation takes place in the unbound layers beneath the asphalt course, it is therefore essential to prioritize attention on these layers. Temperature exerts besides viscosity a substantial impact on asphalt stiffness, leading to the transfer of higher vertical deviatoric stresses to the unbound layers beneath the asphalt course (base, subbase, subgrade). This research presents a study integrating the High Cycle Accumulation (HCA) model into a laminar model to determine permanent deformations in the unbound granular layer of flexible pavements and taking into account the temperature dependent stiffness of asphalt. Rutting depths at the end of the design lifetime were computed, accounting for seasonal stiffness variations. It was shown that the softer asphalt behavior significantly increases the development of ruts in the underlaying soil layers. The findings were compared with results obtained from mean annual temperature and the typical equivalent asphalt stiffness utilized in fatigue tests. Additionally, an analysis was conducted to assess whether the timing of road implementation influences settlements throughout the design lifetime. The results suggest that the sequence of seasons is most relevant during the first year of service, showing a distinct effect at that time. However, with a higher number of axle passes, the initial differences fade away, and the curves start to merge.

Prospective Observational Study Of The Outcome Of Pregnancies With Sonologically Detected Nuchal Cord At Term

Background: Nuchal cord refers to the condition where the umbilical cord wraps around the fetal neck, potentially leading to complications during pregnancy and delivery. The prevalence of nuchal cords at delivery ranges between 6% and 37%, with possible adverse outcomes including fetal asphyxia, hypoxia, and in severe cases, stillbirth. The current study aims to evaluate the impact of nuchal cord detection via ultrasound in fullterm pregnancies and assess its prognostic significance concerning perinatal outcomes. Materials and Methods: This prospective observational study involved a cohort of pregnant women at term (37- 42 weeks of gestation) with sonologically detected nuchal cords. Ultrasound evaluations were conducted to determine the presence and characteristics of nuchal cords, including the number of loops and tightness. The outcomes measured included the mode of delivery, fetal distress, Apgar scores, and neonatal complications such as hypoxic-ischemic encephalopathy (HIE) and meconium aspiration syndrome (MAS). Statistical analysis was performed to assess the correlation between nuchal cord characteristics and perinatal outcomes. Results: The study found that the presence of nuchal cords was associated with an increased rate of cesarean deliveries and a higher incidence of fetal distress during labor. However, the degree of tightness and the number of loops significantly influenced the severity of outcomes. Neonates with tightly looped nuchal cords showed a higher incidence of low Apgar scores and required more intensive neonatal care. The study also observed a slight increase in the occurrence of neonatal complications, including MAS and HIE, among those with multiple nuchal cord loops. Conclusion: The detection of nuchal cords at term via ultrasound is a valuable tool in predicting potential delivery complications. While many nuchal cords do not adversely affect perinatal outcomes, those with multiple loops or tight cords pose a higher risk of complications. This study emphasizes the importance of careful monitoring and tailored management strategies for pregnancies complicated by nuchal cords to optimize maternal and fetal outcomes.

Implementing Explainable Machine Learning Models for Practical Prediction of Early Neonatal Hypoglycemia.

Hypoglycemia is a common metabolic disorder that occurs in the neonatal period. Early identification of neonates at risk of developing hypoglycemia can optimize therapeutic strategies in neonatal care. This study aims to develop a machine learning model and implement a predictive application to assist clinicians in accurately predicting the risk of neonatal hypoglycemia within four hours after birth. Our retrospective study analyzed data from neonates born ≥35 weeks gestational age and admitted to the well-baby nursery between 1 January 2011 and 31 August 2021. We collected electronic medical records of 2687 neonates from a tertiary medical center in Southern Taiwan. Using 12 clinically relevant features, we evaluated nine machine learning approaches to build the predictive models. We selected the models with the highest area under the receiver operating characteristic curve (AUC) for integration into our hospital information system (HIS). The top three AUC values for the early neonatal hypoglycemia prediction models were 0.739 for Stacking, 0.732 for Random Forest and 0.732 for Voting. Random Forest is considered the best model because it has a relatively high AUC and shows no significant overfitting (accuracy of 0.658, sensitivity of 0.682, specificity of 0.649, F1 score of 0.517 and precision of 0.417). The best model was incorporated in the web-based application integrated into the hospital information system. Shapley Additive Explanation (SHAP) values indicated mode of delivery, gestational age, multiparity, respiratory distress, and birth weight < 2500 gm as the top five predictors of neonatal hypoglycemia. The implementation of our machine learning model provides an effective tool that assists clinicians in accurately identifying at-risk neonates for early neonatal hypoglycemia, thereby allowing timely interventions and treatments.

An Afro-cosmological Approach to Marechera’s The House of Hunger (1978)

Abstract Marechera and his literary texts do not fit easily into Africanist categories of reading, principally due to his vitriolic invocation of the ‘f-word’ when asked if he was an African writer. Despite this iconoclasm, Afro-cosmic creeds undeniably inform aspects of his novella. An Afro-cosmological approach acknowledges non-empirical influences for certain behavioural traits portrayed by various characters in the novella which Marechera utilises and assails to address a ‘diseased’ colonial life. Using Falola’s Ritual Archives (2017), we approach this novella as a repository of Shona social ideation and cultural mythologies of haunting, and the Isisism trope of putting material remains back together. Numerous invocations of Shona cosmologies demonstrate Marechera’s socialisation into an African cosmology which manifests itself in his writing and life in unlimited ways. In sum, we interrogate the author’s use of culture codes to relocate him within an African rationale, thus, unmooring him from the Western-centric frameworks emphasised by Veit-Wild’s memoir (2020). We offer insights into the spirituality surrounding Marechera, his vagabondage and his seemingly self-sabotaging behaviour succinctly summarised by Veit-Wild as ‘biting every hand that fed you.’ Flora Veit-Wild, using the logic of a European, fails to appreciate this aspect of his life. In this article we recentre an African cosmology through the topos of being haunted to conceptualise Marechera’s writing and life to account for non-Western occurrences and modes of psychic distress which find no diagnosis in Western psychiatry.

Performance Characterisation of High RA Asphalt Mixes – A Laboratory and Field Study

The research project highlights the significance of incorporating reclaimed asphalt (RA) into hot mix asphalt (HMA) production for sustainable road construction. Despite limited RA utilization in Hungary in the past decades, the project demonstrates the feasibility of manufacturing HMA with significant RA content using advanced technology. The establishment of a capable asphalt plant and the development of laboratory assessments and mix design methodologies laid a solid foundation for future high RA integration in Hungarian road projects. Large-scale production trials confirmed the practicality of integrating high RA content into heavy-duty asphalt mixes with various binder types, including normal bitumen (B), polymer modified binder (PmB), and rubber modified bitumen (GmB). The large-scale validation project described in this paper was based on crucial binder blend designs carried out prior to the trials. Production control and performance-based laboratory testing proved that asphalt mixes can be designed and manufactured with high RA content while maintaining performance standards. Balancing resistance to distress modes like rutting and low-temperature cracking through careful binder blend design and mix design is achievable, even with high RA proportions. Visual assessments and production control indicated the uniformity of high RA content asphalt mixes. The details provided in this paper emphasise the potential for economic and environmental benefits through increased RA utilization in Hungarian road construction.

Analysis of alkali leaching mechanism on as-built cement concrete bridge deck pavement: View from the perspective of mesostructure characteristics

The emergence of a new distress mode, known as alkali leaching, has been increasingly reported in the cement concrete bridge deck pavement (CCBDP). The presence of defects in the pavement structure causes the accumulation and movement of alkaline solution. The examination of the internal pore features of deteriorated pavements is advantageous in order to comprehensively reveal the mechanism of alkali leaching on CCBDP. The present research focuses on analyzing the mesostructure of alkali leaching specimens obtained from distressed pavement. This analysis is conducted using X-Ray Computed Tomography (X-ray CT) and digital image processing (DIP) technologies. In order to assess the correlation between pore characteristics and alkali leaching, a parameter known as the critical pressure difference (CPD) is defined and calculated to quantify the leaching ability. The results show that alkali leaching cores (ALC) have a higher number of voids compared to Normal Cores (NC), particularly for voids of larger volume. Inadequate compaction effort induces vertical connectivity of voids in the alkali leaching pavements, thereby impeding the movement of alkaline solution. A sensitive porosity interval around 4.5 ∼ 5.5 % is found, the DGAC with larger porosity will easily occur leaching phenomenon in the certain CPD section. The correlation between the porosity and the CPD is also identified, indicating that the porosity is the main inherent factor in alkali leaching.

Degradation of Cycle Paths—A Survey in Swedish Municipalities

There is a need to move society in a sustainable direction. One way to contribute to this move is to change to more sustainable transport modes, such as cycling. To increase cycling, the infrastructure is important, and good quality cycle paths are needed. However, little is known about the degradation of cycle paths. This paper aims to investigate what modes of pavement distress are found on municipal cycle paths in Sweden, and what probable mechanisms lie behind such distress; these are determined based on questions from a state-of-practice survey, interviews, and a literature review. The main findings are that the most commonly stated distress modes are surface unevenness followed by longitudinal cracks, and the most commonly stated causes of distress are ageing, followed by structural interventions, and roots and vegetation. The results also show that for several distress modes, there are probable connections with climatic factors such as temperature and moisture, as well as with the population size of the urban areas. Objective data are needed regarding traffic load and the climatic factors that affect cycle paths, along with information on their structural design, to better understand their degradation.

Relationship betwwn Interpersonal Distress and Interpersonal Conflict Management Modes among College Students

Objective To explore the status of college students' interpersonal conflict management modes and interpersonal distress, and analyze the impact of interpersonal conflict management modes on college students' interpersonal distress. Methods 471 college students in Guangdong Province were randomly selected through Internet recruitment. They were investigated with Interpersonal Comprehensive Diagnostic Scale for College Students (ICDS) and Thomas-Kilmann Conflict Mode Instrument (MODE). Results ⑴ The total score of ICDS was (13.49±3.41); The scores of competition, cooperation, compromise, avoidance and accommodation were (7.83±1.40), (6.06±1.58), (6.59±1.37), (5.18±1.25) and (5.67 ±0.94), respectively. (2) There was a significant correlation between the score of each dimension of MODE and the total score of ICDS and the scores of following three dimensions of conversation, making friends and dealing with people (|r| =.175 to .483, all P &lt;. 01). ⑶ The results of multivariate stepwise linear regression showed that competition, avoidance and accommodation were positively correlated with the total score of ICDS（β= . 483, . 461, . 175, all P &lt;. 01), and cooperation and compromise were negatively correlated with the total score of ICDS (β=-.311, -. 298, P &lt;. 01). Conclusion The interpersonal distress of college students is obvious, and their interpersonal communication ability needs to be improved. The interpersonal conflict management mode may be one of the main influencing factors of college students' interpersonal distress.

Effects of actual loading waveforms on the fatigue behaviours of asphalt mixtures

Fatigue cracking is one of the main distress modes of highway asphalt pavements. In laboratory fatigue tests, haversine or sinusoidal loading waves are commonly applied to characterize the fatigue performance of asphalt mixture samples. The strain wave in field asphalt layer under a moving axle load, however, is noticeably different from the haversine or sinusoidal wave. This research compared the fatigue behaviours of compacted asphalt mixture samples under actual strain waves and the commonly used haversine wave. Two types of actual strain waves induced by the single axle and tandem axle of vehicles were included for analysis. It is found that the fatigue lives of asphalt mixture samples subjected to the single-axle wave are obviously higher than those subjected to haversine wave, while the tandem–axle wave leads to the lowest fatigue life. The changing rates of stiffness, phase angle, and dissipated energy with loading cycles for the mixture samples under single-axle wave are all the lowest, while those under tandem-axle wave are all the highest. This helps explain the discrepancies in the samples’ fatigue lives under different loading waves. The above findings suggest that it is necessary to test asphalt mixture samples using loading waves that simulate the actual ones in the field (i.e., single-axle wave and tandem-axle wave) to improve the reliability of fatigue life prediction of asphalt pavements. In addition, this research reveals that three dissipated-energy-based indicators, namely initial dissipated energy, cumulative dissipated energy and plateau value, all generate a unique relationship with the sample’s fatigue life. The relationship is independent of loading wave type and strain level.

Rutting prediction models for flexible pavement structures: A review of historical and recent developments

Rutting is the major distress mode in flexible pavements occurring due to the repeated movement of traffic loading. Deformation in the pavements comprise of both recoverable (elastic) and irrecoverable (plastic) part. Overall deformation occurring in the flexible pavement system due to continuous vehicular movement is contributed from all the components of pavement. A number of empirical models have been proposed by several researchers for analysis and prediction of accumulated rutting in different components of pavement. The accumulated permanent strain has been expressed as the function of the number of load applications and deviator stress applications in most of the models proposed; however, factors such as stress state, moisture content, material type and environmental conditions also impose a significant influence on the permanent deformation characteristics of pavement materials under cyclic loading. In this article, a comprehensive review has been carried out covering every aspect of deformation related to distress occurring in pavements. Important rut models, modeling approaches and modern concepts in the rutting analysis of pavement structures have been presented. In addition to review, fallacy existing in the current design practices related to adaptation of stiffness parameters and negligence of shear strength aspect of subgrade soil has been also presented with the support of literatures. • Permanent strain along with resilient strain must be evaluated for accurate characterization of pavement materials. • Significant rut prediction models for pavement structure and subgrade soil have been discussed. • Limitation related to the adaption of stiffness parameters ( M R , CBR) in flexible pavement design.

Laboratory evaluation of cracking resistance for asphalt mixtures modified with nanoclay and nanocellulose

Cracking failure is one of the major distress modes associated with asphalt pavement. Asphalt modification has been identified as an effective method to improve pavement performance. In this study, nanomaterials including bentonite and halloysite nanoclays and nanocellulose are added to PG 64-28 straight run asphalt binder for modification. The potential of these nanomaterials for improving the cracking performance of asphalt pavements at intermediate pavement service temperatures is investigated. Rheological evaluation is conducted using a dynamic shear rheometer (DSR), and the cracking resistance of the asphalt mixtures is determined through indirect tension asphalt cracking test (IDEAL-CT). A high-shear mixer is used to disperse the nanomaterial in the asphalt and the field emission scanning electron microscope (FESEM) analysis shows a relatively good dispersion of the nanomaterials. Furthermore, the results of the IDEAL-CT show an improvement in cracking test index by as much as 47%–114% through nanomaterial modification.

Flexible Pavement Components for Optimum Performance in Rutting and fatigue (Dept.C)

Premature failure of flexible pavements has long been a problem in many Egyptians roads with the drastic increase in truck axle loads. To fully utilize each pavement material in an economic design, a pavement should generally have reasonably balanced design between the rutting and fatigue modes of distress. The purpose of this paper is to develop a methodology for achieving a reasonable balance between fatigue and rutting lives of flexible pavements. The methodology is based on the damage analysis concept which is performed for both fatigue cracking and rutting on different pavement sections using KENLAYER program. The investigated pavement components are; thickness (d1 and d2) and elasticity modulus (E1 and E2) for asphalt layer and base layer, respectively, and subgrade elasticity modulus (E3). The results of pavement analysis showed that d2 and E3 are the key elements which control the equilibrium between fatigue and rutting lives (Nr, and Nr, respectively). That is because, increasing d2 and E3 sharply increases Ng, and don't affect in Nr. The study also concluded that, increasing dl significantly increases both Nf and Nr, while increasing E2 and El mildly increases Nf and Nr. Finally, the study has recommended pavement sections with any values of d1, El or E2 at d2 = 12-in. along with E3 = 8,000 psi, for optimum utilization of pavement components with respect to fatigue and rutting.

Rutting Resistance of Asphalt Pavement Mixes by Finite Element Modelling and Optimisation

Asphalt pavement rutting is a major safety concern and is one of the main distress modes of asphalt pavement. Research into asphalt pavement mixes that provide strong resistance for rutting is considered of great significance as it can help provide extended pavement life and significant cost savings in pavement maintenance and rehabilitation. The objectives of this study are to develop numerical models to investigate the rutting of asphalt concrete pavements and to find optimal design of asphalt pavement mix for rutting resistance. Three-dimensional Finite Element models were first developed to simulate both the axial compression and wheel track testing in which a visco-elastic-plastic material model was used to predict the rutting of the asphalt concrete pavements. A strain hardening creep model with the material parameters developed from experimental testing was employed to model the time-dependent characteristics of the asphalt concrete pavements. The results were validated against the previous experimental wheel track test results of different pavement mixes. Finally, optimisation techniques using the Design Of Experiments method were applied to the simulation rutting results by varying creep parameters to identify their effects on rutting resistance in order to obtain an optimal asphalt pavements mixes. The results of this paper clearly demonstrate an efficient and effective experimental-numerical method and tool set towards optimal design for asphalt concrete pavements for rutting resistance.

A method for bottom-up cracks healing via selective and deep microwave heating

The expected life of an asphalt road pavement depends on many factors (fatigue cracking, thermal cracking, etc). Bottom-up cracking is a common mode of hot mix asphalt pavement distress and appears to be critical. In view of this, the objectives of the study presented in this paper were confined into setting up an innovative and non-destructive method to carry out the rehabilitation of the pavement structure. In particular, a new procedure for healing in-depth damaged asphalt pavements is proposed and discussed. This method, based on selective heating, uses appropriate doping and electromagnetic fields in the microwave frequency range in order to induce the self-healing process of the material. Compared to the existing procedures, it allows a deep, selective, adaptive, and not invasive healing. The procedure, numerically validated by multi-physical simulations, can be applied to all solid structures made up of materials wherein the self-healing process can be induced by heating.

Correlations and preliminary validation of the laboratory monotonic overlay test (OT) data to reflective cracking performance of in-service field highway sections

Reflective cracking is one of the dominant distress modes occurring when hot-mix asphalt (HMA) overlays are placed over existing cracked flexible and/or jointed rigid pavements. In the laboratory setting, there are various tests – both of dynamic and monotonic loading modes – that can be used to measure, characterize, and quantify the cracking resistance potential of HMA mixes. However, one key challenge with most of these laboratory tests is correlations and validation with field performance data. Quite often, field data availability is a challenge or otherwise, needs costly long-term performance monitoring. Using the Texas flexible pavements and overlays database, namely the Texas Data Storage System (DSS), as the data source, this study was conducted to correlate and preliminarily validate the laboratory monotonic-loading overlay tester (OT) to the field crack performance of in-service highway sections. As excerpted from the DSS, four HMA mixes and six in-service highway sections (overlays) were used. Overall, the monotonic-loading OT test exhibited promising potential as a repeatable test (coefficient of variation [COV] < 30%) for evaluating and quantifying the cracking resistance potential of HMA mixes in the laboratory relative to the field performance of in-service highway sections. In particular, the following HMA fracture parameters, fracture energy (FE), tensile strength (σt), FE Index, and peak load (Pmax) from the monotonic-loading OT test, with COV values less than 30%, were able to statistically differentiate the HMA mixes (statistical groups ≥ 2) and also correlated well (coefficient of determination [R2] > 60%) with the measured field cracking performance data.

An overview of asphalt pavement design for streets and roads

Pavements are geotechnical problems; consequently, a geotechnical framework is useful to describe their constitutive elements. The design of asphalt pavements for streets and roads evolved from empiric to mechanistic-empiric (M-E) procedures throughout the 20th century. The mechanistic-empiric method, based on layered elastic theory, became a common practice with the publication of separate procedures by Shell Oil, Asphalt Institute, and French LCPC, among others. Since its origin, the M-E procedure can consider incremental pavement design but, only until the beginning of the 21st century, the computational power became available to practicing engineers. American MEPDG represents the state-of-the-art M-E incremental design procedure with significant advantages and drawbacks, the latter mainly related to the extensive calibration activities required to assure a proper analysis and design according to subgrade, climate, and materials at a particular location and for an intended level of reliability. Perpetual pavements are a subset of M-E designed pavements with a proven history of success for the particular conditions where they are warranted. No design method, either the most straightforward empirical approach or the most elaborated incremental mechanistic one, is appropriate without proper knowledge about the fundamental design factors and calibration of the performance models for each distress mode upon consideration.

Fatigue-Based Structural Layer Coefficient of High Polymer-Modified Asphalt Mixtures

Florida Department of Transportation uses the 1993 AASHTO guide to conduct new and rehabilitation designs for all the state’s flexible pavements. Based on previous experience, a structural layer coefficient of 0.44 was found to be well representative of the department’s conventional polymer-modified (PMA) asphalt concrete (AC) mixtures. If the positive impact of the polymer on the layer is assumed to be maintained at higher contents, then the use of high polymer-modified (HP) asphalt binder may lead to a higher AC structural layer coefficient and a reduced AC layer thickness for the same design traffic and serviceability design loss. The objective of this paper was to determine a fatigue-based structural layer coefficient for asphalt mixtures that contain HP binder using comprehensive mechanistic analyses. This approach relied on combining measured engineering properties and performance characteristics of AC mixtures with advanced flexible pavement modeling (3D-Move). A total of eight PMA and eight HP AC mixtures were designed and evaluated in the laboratory. Overall, the HP AC mixtures showed similar or lower dynamic modulus and better fatigue performance models when compared with those of their respective PMA AC mixtures. However, the fatigue-based structural layer coefficients, determined via mechanistic analysis using the service life approach, ranged between 0.33 (lower than 0.44) and 1.32 (greater than 0.44). Using advanced statistical analyses, a fatigue-based structural layer coefficient of 0.54 was determined for HP AC mixtures. This coefficient should still be verified for other modes of distress.

A Cross-sectional Study of Group B Streptococcus–Associated Sepsis, Coinfections, and Antibiotic Susceptibility Profile in Neonates in Pakistan

Neonatal sepsis is a leading cause of morbidity and early-life mortality worldwide, and previous data have reported the highest neonatal mortality rate in Pakistan. The present study aimed to decipher the prevalence of group B Streptococcus (GBS)-associated sepsis, coinfections, and antibiotic susceptibility of isolated microbes in neonates. Blood samples of 100 cases of neonatal sepsis were subcultured on blood agar, GBS agar, and MacConkey agar for isolation of GBS and suspected microbes. Of 100 neonatal blood samples, 85 blood samples were culture-positive, including mixed culture growth (n = 18), 25 samples as early-onset neonatal sepsis (EONS) and 60 as late-onset neonatal sepsis (LONS). Staphylococcus aureus showed high percent positivity (31.4%), followed by Candida sp (16.5%), GBS (14.1%), Klebsiella (14.1%), Staphylococcus epidermidis (11.8%), Pseudomonas (9.4%), Acinetobacter (9.4%), Esherichia coli (8.2%), and Enterococcus (5.9%). GBS was isolated more frequently from EONS than from LONS with 50% coinfections. Mode of delivery, gender, and respiratory distress in neonates were significantly associated with culture-positive sepsis. GBS isolates were highly (91.7%) susceptible to vancomycin, cefotaxime, and chloramphenicol, followed by penicillin (83.3%), ampicillin, and tetracycline (75%). GBS isolates were resistant to erythromycin, clindamycin, ciprofloxacin, and linezolid. Our findings evidenced GBS-associated risk factors and antibiotic susceptibility pattern of neonatal sepsis, which will help clinicians in management, control, and treatment of neonatal sepsis. The epidemiological evidence of GBS-associated neonatal sepsis, demographic characteristics, risk factor data analysis, and drug resistance pattern has disease prevention implications in neonates in low-income countries including Pakistan.

Relation between maternal C–reactive protein in early pregnancy and neonatal complications

Background C-reactive protein (CRP) is an acute-phase reactant and a commonly employed indicator of low-grade systemic inflammation. Elevated CRP levels are accompanied by higher risk of popular diseases. This study aimed to study the correlations of maternal CRP level with fetal growing and the risk of neonatal complications. Participants and methods This prospective observational randomized study was conducted in Al Zahraa University and El Sheikh Zayed hospital throughout the interval from April 2018 to March 2020. It included 150 pregnant women attending for antenatal care in the outpatient clinic. CRP was done twice. The first measure was done at second trimester (13–20 weeks), and the second measure was done after 26 weeks. Positive results were obtained at a CRP concentration above 10 mg/l. The pregnant women were subdivided into two groups: group A, with positive (high) CRP, and group B, with negative (ordinary CRP). Follow-up was done by ultrasound during pregnancy [to detect Intrauterine Growth Restriction (IUGR), low birth weight, and congenital anomalies]. Follow-up during labor was done to detect mode of delivery, IUGR, respiratory distress, and NICU admission. Results Median CRP level at 13–20 weeks was higher than median CRP level at 26–30 weeks. Regarding CRP finding, it was found that ∼60 (40%) women had positive CRP and 90 (60%) women had negative CRP. IUGR was statistically significantly higher among positive CRP group than negative CRP group (5 and 0%, respectively; P=0.031). Respiratory distress was statistically significantly higher among positive CRP group than negative CRP group (6.7 and 0%, respectively) (P=0.01). Admission at neonatal ICU was statistically significantly higher among positive CRP group than negative CRP group (6.7 and 0%, respectively; P=0.031). Conclusion Maternal-grade inflammation in pregnancy, as estimated by CRP counts, was accompanied with fetal growing restriction and higher risks of neonatal complications.

Analysis and design of two layered flexible pavement systems: A new mechanistic approach

Analysis of two layered flexible pavements is considered as a significant aspect for design of low volume roads, which typically consist of a thick granular base course directly laid over subgrade with or without a thin asphalt-wearing course. Permanent deformation or rutting has been observed to be the major distress mode in thin surfaced or unsurfaced low volume roads. In the present study, a new formulation has been proposed to determine the surface and interface deflections for both single and standard axle dual wheel assembly for a two layered pavement system. The present formulation has been developed based on mechanistic approach and the solutions obtained from 3-dimensional finite element program, using ABAQUS taking into account the influence of rectangular tire imprint, modulus of granular base course, pavement thickness and ratio of modulus of pavement and subgrade. The effect of Poisson’s ratio of granular base and subgrade is observed to be very insignificant. For the estimation of surface and interface deflections, deflection factors have been generated in the form of non-dimensional charts as a function of ratio of modulus of pavement and subgrade, and ratio of pavement thickness and tire width.