Experimental Study on Geocell-Reinforced Recycled Asphalt Pavement (RAP) Bases under Static and Cyclic Loading

Recycled Asphalt Pavement (RAP) is a removed and reprocessed pavement material containing asphalt and aggregates which can be used as a base course material for pavement applications. Geocells are a three-dimensional interconnected honeycomb type of geosynthetics used to reinforce weak soils and base courses of roads and are ideal for soil confinement. The objectives of this study are to evaluate characteristics of milled recycled asphalt pavement (RAP) collected from a city street in Lawrence, Kansas and to investigate the creep and cyclic behavior of geocell-reinforced RAP bases over rigid subgrade under static loading and over weak subgrade under cyclic loading through laboratory testing respectively. The compaction and CBR curves were obtained for the RAP. The Mohr-Coulomb failure envelopes for RAP and RAP/geocell interface were obtained by direct shear tests. The asphalt binder and the aggregates were extracted from RAP. The extracted aggregates were tested for their properties including gradation, specific gravity, and fine aggregate angularity (FAA). The viscosity of the extracted asphalt binder was also determined. The results indicated that the asphalt content obtained by the ignition method was slightly higher than that by the centrifuge method. Gradation results indicated that the compaction did not change the gradation of the RAP. Fourteen medium-scale laboratory static plate loading tests were conducted on RAP samples under two vertical stresses at different confining conditions to investigate the creep deformation behavior of geocell-reinforced RAP bases. The creep axial strains at different time were estimated for RAP at different confining conditions and vertical stresses. The results indicated that the geocell confinement significantly reduced the initial deformation and the rate of creep of the RAP bases. Six medium-scale plate loading tests at different confining conditions and one unconfined compression test were conducted on RAP samples by applying static loads in increment to understand the pressure-displacement response and evaluate the bearing capacity and stiffness of the unreinforced and geocell-reinforced RAP bases. The results indicated that geocell significantly increased the bearing capacity and stiffness of RAP bases. Nine large-scale laboratory cyclic plate loading tests were conducted on RAP base sections with three different base course thicknesses. The novel polymeric alloy (NPA) geocells were used to reinforce the RAP bases. The behavior of unpaved RAP bases, such as permanent deformation, percentage of elastic deformation, stress distribution, and strains in the geocell walls was investigated. The results indicated that the geocell effectively reduced permanent deformation, and vertical stress at the interface of base and subgrade and increased the stress distribution angle and increased percentage of elastic deformation. The strain measurements demonstrated that the geocell-reinforced RAP bases behaved as a slab

Geocell-Reinforced Unpaved and Paved Roads with Recycled Asphalt Pavement (RAP) Bases: Experimental Study and Damage Model Development

Recycled Asphalt Pavement (RAP) is a removed and reprocessed pavement material from deteriorated asphalt pavements containing asphalt binder and aggregates. The use of RAP can reduce the cost of construction materials, reduce the amount of waste to be land-filled, and conserve natural resources by requiring less virgin aggregate and asphalt in road construction projects. Literature showed that RAP bases had more permanent deformation under static and dynamic loading compared to conventional aggregate base. Geocell is one type of geosynthetic products manufactured in a form of three-dimensional interconnected honeycomb shape polymeric cells. Geocell was used in this study to reinforce RAP bases in unpaved and paved roads. The objective of this study is to understand the behavior of unpaved and paved roads with unreinforced and geocell-reinforced RAP bases. Fifteen large-scale laboratory cyclic plate loading tests were conducted on unpaved and paved road sections with unreinforced or geocell-reinforced RAP bases. The unpaved road sections consisted of unreinforced or geocell-reinforced RAP bases over weak or moderate (target CBR = 2% or 5%) subgrade, whereas paved road sections consisted of hot mix asphalt (HMA) surface over unreinforced or geocell-reinforced RAP bases over moderate (target CBR = 5%) subgrade to investigate their performance and shake down responses under cyclic loading. The test results showed that geocell improved the performance of RAP bases as compared with the unreinforced bases by increasing the percentage of resilient deformation and reducing the permanent deformations and the vertical stresses transferred to the subgrade. A thin (about 50 mm) HMA surface significantly improved the performance of RAP bases. The thicker geocell-reinforced RAP base behaved as a slab with bending resistance and the thinner base behaved as a slab initially at a smaller deformation and then as a tensioned membrane at a larger deformation. The geocell-reinforced RAP bases showed a stable shakedown response whereas the unreinforced RAP base showed an unstable shakedown response. Based on cyclic plate loading test results, damage models for the empirical correlation between the permanent strain and/or the resilient strain with the number of loading cycles were developed for unpaved and paved roads including unreinforced and geocell-reinforced RAP bases. The mechanistic empirical model can be incorporated in the AASHTO Mechanistic Empirical Pavement Design Guide (MEPDG), which will promote the sustainable use of RAP with geocell for roadway construction

Planktonic Scenario of the River Ganga & Yamuna at Prayagraj in COVID-19 Lockdown: A Case Study

Ganga is the most prestigious river of India. The COVID-19 lockdown may have forced us to stay indoors, but it has been boon for pollution-ridden Ganga and Yamuna. Plankton is tiny organisms drifting with water current, influenced by river physical and chemical factors. During lockdown anthropogenic factors were reduced which affected water and plankton quality. Plankton samples were collected from the upstream of the river Ganga (Shankerghat, latitude 25030’28” N and longitude, 81052’10”E) and Yamuna (near boat club, latitude 25024’29”N and longitude 81054’50”E) at Prayagraj, during national lockdown. In the before lockdown period (2019), total 28 planktonic taxa were recorded from the river Ganga, among them 10 taxa from Bacillariophyceae, 15 from Chlorophyceae and 3 from Myxophyceae. While during LD period total 54 genera with 86 species was recorded (Bacillariophyceae 10 taxa, Chlorophyceae 23 taxa, Myxophyceae 9 taxa, Euglenophyceae 2 taxa, Dianophyceae, 1, Rotiferea 7 taxa, Protozoa 2 taxa). Various species of green algae were observed in this small period of lockdown, some species were not observed since a long, like Pediastrum tetras, Scenedesmus abundans, Ankistrodesmus fusiformis, and Brachionus angularis. Various species of phytoplankton and zooplankton were in reproductive phase because river was flowing silently, without any internal and external disturbance. Ganga was more affected by anthropogenic activity and factory discharge than Yamuna So lack of chemicals in the water and minimum human interference favoured auto rejuvenation of Ganga in terms of plankton quality, diversity and reproduction behaviour. Such type of environmental changes may stimulate for origin of new species and disappear or reappear of various aquatic species

Usunięcie przemieszczonych stentów z pnia lewej tętnicy wieńcowej w trakcie przezskórnej interwencji wieńcowej techniką trappingu

Dislodgement and embolisation of the new generation of drug eluting stents is a very rare but recognized and potentially serious complication of percutaneous coronary intervention (PCI). Various methods from including tangling wire, bioptome, and goose neck snare to surgical removal have been described. Here we report a case of successful retrieval of a deformed coronary stent from left main coronary artery by trapping technique.Przemieszczenie stentu nowej generacji wydzielającego lek i związany z tym zator to bardzo rzadkie, lecz znane powikłanie przezskórnej interwencji wieńcowej, które może się wiązać z poważnymi następstwami. Opisywano różne metody chirurgicznego usunięcia stentu z życiem rozmaitych narzędzi endoskopowych, w tym narzędzi z końcówką w postaci splątanego drutu, szczypczyków biopsyjnych i pętli. W niniejszej pracy przedstawiono przypadek skutecznej ewakuacji zdeformowanego stentu wieńcowego z pnia lewej tętnicy wieńcowej techniką trappingu

Acute dislocation of fully deployed stent after use of non-compliant balloon: an enigma

Stent embolism is an established but rare complication of percutaneous coronary intervention, usually encountered when an undeployed stent unintentionally dislocates from the balloon. Published literature regarding incidence or clinical outcomes of embolism of fully deployed coronary stents is sparse. Here we report an unusual case of a 41-year-old male who had dislocation of a fully deployed stent into the distal part of left anterior descending artery following post dilatation by non-compliant balloon during percutaneous coronary intervention

Nietypowy elektrokardiograficzny zapis zaburzeń przewodzenia po zastosowaniu chlorochiny — opis rzadkiego przypadku

23-year-old man presented with Stokes-Adams attacks due to sinus node dysfunction. He was being treated for malaria with chloroquine for the last two days. Temporary pacemaker was implanted. Subsequently he developed all spectrum of atrioventricular block following recovery of sinus node dysfunction which also recovered on the fi fteenth day and was discharged. Cardiac damage, such as cardiomyopathy and conduction system disturbances, is regarded as uncommon consequences of acute chloroquines’s toxicity. Here we present a case in which chloroquine used as acute therapy for malaria resulted in conduction disorder beginning from sinus node dysfunction to Mobitz I atrioventricular block to complete heart block with recovery to normal sinus rhythm in single patient.Mężczyzna w wieku 23 lat zgłosił się do lekarza z powodu napadów Morgagniego-Adamsa-Stokesa będących następstwem dysfunkcji węzła zatokowego. Przez ostatnie 2 dni stosował chlorochinę w ramach leczenia przeciwmalarycznego. Tymczasowo wszczepiono mu stymulator serca. Po ustąpieniu zaburzeń węzła zatokowego u chorego rozwinął się pełny blok przedsionkowo-komorowy, który również ustąpił po 15 dniach i chorego wypisano do domu. Uszkodzenie serca w postaci kardiomiopatii lub zaburzeń przewodzenia jest rzadkim następstwem ostrego toksycznego działania chlorochiny. W artykule przedstawiono przypadek pacjenta, u którego po zastosowaniu chlorochiny w leczeniu ostrego napadu malarii wystąpiło całe spektrum zaburzeń przewodzenia — od dysfunkcji węzła zatokowego, przez blok przedsionkowo-komorowy typu Mobitz I, do całkowitego bloku przedsionkowo komorowego — zakończonych przywróceniem prawidłowego rytmu zatokowego

Izolowana ciężka stenoza trójpłatkowej zastawki aortalnej u 8-letniego chłopca

A 8-year-old boy was referred for evaluation of ejection systolic murmur. On examination multiple xanthomas and xanthelesmas were noted. Investigations confirmed familial hypercholesterolemia and severe aortic stenosis in background of tricuspid aortic valve. We report a case of severe aortic stenosis in background of morphologically normal valve, a rare complication of heterozygous familial hypercholesterolaemia.Ośmioletni chłopiec został skierowany do ośrodka w celu oceny skurczowego szmeru typu wyrzutowego. W badaniu przedmiotowym stwierdzono liczne kępki żółte i kępki żółte płaskie. Na podstawie przeprowadzonych badań rozpoznano hipercholesterolemię rodzinną (FH) i ciężką stenozę zastawki aortalnej o budowie trójpłatkowej. Autorzy opisują przypadek ciężkiej stenozy aortalnej u pacjenta z prawidłową morfologicznie zastawką aortalną, co jest rzadkim powikłaniem heterozygotycznej postaci FH

Percutaneous retrieval of a fractured multipurpose catheter by an indigenous snare in a 25-year-old patient: a safe and feasible approach

Since the first report of percutaneous retrieval of intravascular foreign body in 1964, it has become a favourite approach for intravascular foreign body removal. Snares, biopsy forceps, dormia basket or tip deflecting wires are available options for this approach. Herein, we report percutaneous retrieval a fractured multipurpose catheter by an indigenous snare in a 25-year-old patient. The patient was a 25-year-old male being admitted with ostium secundum atrial septal defect and catheterization study was planned for shunt quantification. During manipulation to right ventricular outflow tract, multipurpose catheter got broken approx. 4 cm. proximal to tip. The broken part was captured through right femoral vein by a self-constructed snare. While removal, it broke at tip of venous sheath. Smaller one was retrieved and bigger was recaptured and finally retrieved by exaggerating the curve of same snare without any complications. Use of snares for intravascular foreign body removal is frequently reported and has been successful with low complication rates.Since the first report of percutaneous retrieval of intravascular foreign body in 1964, it has become a favourite approach for intravascular foreign body removal. Snares, biopsy forceps, dormia basket or tip deflecting wires are available options for this approach. Herein, we report percutaneous retrieval a fractured multipurpose catheter by an indigenous snare in a 25-year-old patient. The patient was a 25-year-old male being admitted with ostium secundum atrial septal defect and catheterization study was planned for shunt quantification. During manipulation to right ventricular outflow tract, multipurpose catheter got broken approx. 4 cm. proximal to tip. The broken part was captured through right femoral vein by a self-constructed snare. While removal, it broke at tip of venous sheath. Smaller one was retrieved and bigger was recaptured and finally retrieved by exaggerating the curve of same snare without any complications. Use of snares for intravascular foreign body removal is frequently reported and has been successful with low complication rates

Skuteczne usunięcie przemieszczonego prowadnika z końcówką w kształcie „J” za pomocą samodzielnie skonstruowanej pętli u 75-letniego pacjenta — bezpieczna i dostępna metoda

Since the first report of percutaneous retrieval of intravascular foreign body in 1964, it has been accepted as a favourite approach for intravascular foreign body removal. Snares, biopsy forceps, dormia basket or tip deflecting wires are available in the armamentarium for this approach. Herein, we report percutaneous retrieval of a dislodged J-tip guide-wire by self-constructed snare. A patient was a 75-year-old woman who was admitted with capture failure following post pacemaker implantation. J-tip guide-wire was inadvertently left in her inferior vena cava during temporary pacemaker insertion. The guide wire was approached through right subclavian vein by a self-constructed snare and it was removed without any complications. Use of snares for intravascular foreign body removal is frequently reported and has been successful with low complication rates; also, the low cost of such snares makes it safe and economical.Od publikacji pierwszego doniesienia o przezskórnym usunięciu śródnaczyniowego ciała obcego w 1964 roku metoda ta jest najczęściej wybieraną techniką w przypadku śródnaczyniowej lokalizacji ciała obcego. Dostępne instrumentarium do takich zabiegów obejmują pętle, kleszczyki biopsyjne, koszyki typu dormia oraz prowadniki z giętką końcówką. W niniejszej pracy opisano przezskórne usunięcie przemieszczonego prowadnika z końcówką w kształcie „J” za pomocą pętli własnej konstrukcji. Kobieta w wieku 75 lat została przyjęta do placówki medycznej po nieudanej próbie usunięcia ciała obcego pozostałego po wszczepieniu stymulatora serca. Podczas wprowadzania czasowego stymulatora przypadkowo pozostawiono prowadnik z końcówką w kształcie „J” w żyle głównej dolnej pacjentki. Prowadnik uchwycono za pomocą pętli własnej konstrukcji wprowadzonej przez prawą tętnicę podobojczykową, a następnie wydobyto bez powikłań. Dostępnych jest wiele publikacji opisujących wykorzystanie pętli do usuwania śródnaczyniowych ciał obcych jako metody skutecznej i cechującej się niskim odsetkiem powikłań. Niskie koszty tego rodzaju pętli sprawiają, że metoda ta jest nie tylko bezpieczna, ale i ekonomiczna