Pipe Rehabilitation with Polyethylene Pipe Liners, HR-370, Construction Report, 1995

Corroded, deteriorated, misaligned, and distorted drainage pipes can cause a serious threat to a roadway. Normal practice is to remove and replace the damaged drainage structure. An alternative method of rehabilitating these structures is to slip line them with a polyethylene liner. Twelve drainage structures were slip lined with polyethylene liners during 1994 in Iowa. Two types of liners installed were "Culvert Renew" and "Snap-Tite". It was found that the liners could be easily installed by most highway, county, and city maintenance departments. The liners restore the flow and increase the service life of the original drainage structure. The liners were found to be cost competitive with the removal and replacement of the existing drainage structure. Slip lining has the largest economic benefit when the roadway is paved, the culvert is under a deep fill, or traffic volumes are high. The annular space between the original pipe and the liner was filled with flowable mortar. Care should be taken to properly brace and grout the annular space between the liner and the culvert.

Seguiment temporal de la reserva marina de les Illes Medes - I. Informe anual. Any 1995

Els seguiments o monitoritzacions, com els empenys humans, tenen per tret diferencial els alts i baixos, les dents de serra. I aixó, no només és vàlid per al comportament de les variables monitoritzades, sino també per als avatars administratius i financers. Fins l'extrem que la continuitat temporal, i no sols l'antiguitat delsregistres, és la millor mesura de la seriositat en la gestió d'un país; en aquest sentit, és evident que els països anglo-saxons tenen molt que ensenyar als llatins (p.e. en els registres de dades metereològiques).Abans del que haguèssim volgut, els alts i baixos polítics i financers van tocar, fent trontollar l'any 1995, al Seguiment del Patrimoni Biològic de les Illes Medes. L'any 1994 s'acabà el primer cicle del Pla d'Usos de l'Àrea protegida de les illes Medes (sorgit de la llei 19/1990 de 10 de desembre del Parlament de Catalunya).Aquest havia d'obrir les portes a un segon cicle quatrienal en el que, de forma preceptiva segons l'esmentada llei, s'havien de continuar els controls biològics del seu patrimoni natural. Per tant, no calia recorrer al nostre reiterat argument que en ecologia hom precisa de períodes d'estudi relativament llargs per definir amb fiabilitat les tendències de canvi: l'administració havia assumit l'argument i el feia seu. Malgrat tot, no podem dir que causès sorpresa la notícia que, després de moltes dil.lacions, informacions contradictòries i canvis de titularitat en els òrgans de gestió, el seguiment de 1995 es veia desproveït de suport financer (ens apresurem a reconeixer que a nivell d'intencions, el suport de les administracions involucrades no es va veure mai compromés). Conscients de la ingenuïtat d'esperar un suport lliure d'entrebancs, el nostre equip de treball havia assumit, des de l'inici del seguiment en 1990, el risc d'aquesta eventualitat. I havia previst que, arribat el cas, caldria continuar el seguiment, omplint si calia el buit derivat de la manca del marcadministratiu (en aquest cas el nou conveni entre la conselleria d'Agricultura, Ramaderia i Pesca i la Universitat de Barcelona) que per motius diversos no es restablí en tot el curs del 1995. És així que el seguiment del patrimoni natural de l'Àrea protegida de les illes Medes al llarg de l'any 1995 es feu amb recursos propis, la qual cosa vol dir amb moltes estretors econòmiques. Afortunadament, la situaciós'ha redrecat, en renovar-se per tres anys més (1996-1998) el conveni que estableix el seguiment. La satisfacció per la signatura d'aquest nou conveni, em fa alimentar l'esperança que ens anys a venir els nous gestors de la Reserva Marina de les Illes Medes, conscients del paper capdavanter d'aquest espai en la gestió dels espais litorals mediterrànis, no permetràn que tals anomalies es repeteixin.

Estado biológico de la pradera de Posidonia oceanica de las Islas Medas. Informe de 1995

Podeu consultar l'Informe complet a: http://hdl.handle.net/2445/24663

Seguiment temporal de la gorgonia Paramuricea clavata de les Illes Medes. Exercici 1995

Podeu consultar l'Informe complet a: http://hdl.handle.net/2445/24663

Seguiment temporal de la garota comuna Paracentrotus lividus en les Illes Medes. Exercici 1995

Podeu consultar l'Informe complet a: http://hdl.handle.net/2445/24663

Avaluació de la població de llagostes (Palinurus elephas) de les Illes Medes. Exercici 1995

Podeu consultar l'Informe complet a: http://hdl.handle.net/2445/24663

Impacte de la freqüentació dels escafandristes sobre les poblacions del briozou Pentapora fascialis a les Illes Medes: Seguiment 1992-1995

Podeu consultar l'Informe complet a: http://hdl.handle.net/2445/24663

Avaluació de la població de corall Corallium rubrum de les Illes Medes. Any 1995

Podeu consultar l'Informe complet a: http://hdl.handle.net/2445/24663

Seguiment de la població de meros (Epinephelus Marginatus) i d'altres espècies vulnerables de les illes medes i la costa veïna parcialment protegida (1991-2000)

Podeu consultar l'Informe complet a: http://hdl.handle.net/2445/23669

Seguiment de la població de meros (Epinephelus Marginatus) i d'altres espècies vulnerables de les Illes Medes i la costa veïna parcialment protegida (1991-2001)

Podeu consultar l'Informe complet a: http://hdl.handle.net/2445/23672

Seguiment de la població de meros (Epinephelus marginatus) i d'altres espècies vulnerables de les Illes Medes i la costa veïna parcialment protegida (1991-2002)

Podeu consultar l'Informe complet a: http://hdl.handle.net/2445/23675

Seguiment de la població de meros (Epinephelus marginatus) i d'altres espècies vulnerables de les Illes Medes i la costa veïna parcialment protegida (1991-2003)

Podeu consultar l'Informe complet a: http://hdl.handle.net/2445/23677

Low Cost Fly Ash - Sand Stabilized Roadway Des Moines County, HR-259, 1991

The objectives of this research were to develop a low cost fly ash-sand stabilized roadway and to correlate field performance with pavement design assumptions on a county road heavily trafficked by trucks hauling grain. The road was constructed during the summer of 1984. Three test sections comprised of different base thicknesses were incorporated in the roadway and were tested for compressive stength, structural rating, and rut depth. Annual crack surveys showed no appreciable difference in transverse cracking between the test sections and little to no rutting. The sandbase drainage characteristics beneath the roadway may have contributed to the satisfactory performance of the test sections. This project indicates that in spite of the inflated cost of construction due to the research nature of the work, a fly ash-sand base can be a viable alternative for roadway stabilization.

Micro-Computer Based Linear Scheduling Application for Highway Construction Project Control, HR-339A, 1995

This report describes a new approach to the problem of scheduling highway construction type projects. The technique can accurately model linear activities and identify the controlling activity path on a linear schedule. Current scheduling practices are unable to accomplish these two tasks with any accuracy for linear activities, leaving planners and manager suspicious of the information they provide. Basic linear scheduling is not a new technique, and many attempts have been made to apply it to various types of work in the past. However, the technique has never been widely used because of the lack of an analytical approach to activity relationships and development of an analytical approach to determining controlling activities. The Linear Scheduling Model (LSM) developed in this report, completes the linear scheduling technique by adding to linear scheduling all of the analytical capabilities, including computer applications, present in CPM scheduling today. The LSM has tremendous potential, and will likely have a significant impact on the way linear construction is scheduled in the future.

Bentonite Treatment for Economical Dust Reduction on Limestone Surfaced Secondary Roads, HR-351, 1995

This research project was directed at laboratory and field evaluation of sodium montmorillonite clay (Bentonite) as a dust palliative for limestone surfaced secondary roads. It was postulated that the electrically charged surfaces (negative) of the clay particles could interact with the charged surfaces (positive) of the limestone and act as a bonding agent to agglomerate fine (-#200) particulates, and also to bond the fine particulates to larger (+#200) limestone particles. One mile test roads were constructed in Tama, Appanoose, and Hancock counties in Iowa using Bentonite treatment levels (by weight of aggregate) ranging from 3.0 to 12.0%. Construction was accomplished by adding dry Bentonite to the surfacing material and then dry road mixing. The soda ash/water solution (dispersing agent) was spray applied and the treated surfacing material wet mixed by motor graders to a consistency of 2 to 3 inch slump concrete. Two motor graders working in tandem provided rapid mixing. Following wet mixing the material was surface spread and compacted by local traffic. Quantitative and qualitative periodic evaluations and testing of the test roads was conducted with respect to dust generation, crust development, roughness, and braking characteristics. As the Bentonite treatment level increased dust generation decreased. From a cost/benefit standpoint, an optimum level of treatment is about 8% (by weight of aggregate). For roads with light traffic, one application at this treatment level resulted in a 60-70% average dust reduction in the first season, 40-50% in the second season, and 20-30% in the third season. Crust development was rated at two times better than untreated control sections. No discernible trend was evident with respect to roughness. There was no evident difference in any of the test sections with respect to braking distance and braking handling characteristics, under wet surface conditions compared to the control sections. Chloride treatments are more effective in dust reduction in the short term (3-4 months). Bentonite treatment is capable of dust reduction over the long term (2-3 seasons). Normal maintenance blading operations can be used on Bentonite treated areas. Soda ash dispersed Bentonite treatment is estimated to be more than twice as cost effective per percent dust reduction than conventional chloride treatments, with respect to time. However, the disadvantage is that there is not the initial dramatic reduction in dust generation as with the chloride treatment. Although dust is reduced significantly after treatment there is still dust being generated. Video evidence indicates that the dust cloud in the Bentonite treated sections does not rise as high, or spread as wide as the cloud in the untreated section. It also settles faster than the cloud in the untreated section. This is considered important for driving safety of following traffic, and for nuisance dust invasion of residences and residential areas. The Bentonite appears to be functioning as a bonding agent.