Roads in many northern climates like Saskatchewan can undergo structural failure caused by frost action and substructure moisture problems. Frost action can be efficiently controlled by eliminating at least one of the following conditions: moisture; freezing temperatures; and frost susceptible soils. However, effective use of shredded tire material could provide an environmentally sustainable solution for waste tires and could relieve pressure on limited quality aggregate resources. The City of Saskatoon has successfully incorporated crushed rock and crushed recycled concrete as a subsurface road drainage layer to mitigate substructure drainage and frost issues. However, the price of crushed high value aggregates can be cost prohibitive and at times these materials are not available in quantities required. Previous research has documented that shredded tires are efficient in controlling frost action by providing thermal insulation and free drainage, but shredded tires performed poorly as a structural support layer with low mechanical stiffness and high compressibility properties. The goal of this research was to provide improved pavement performance with respect to road substructure moisture drainage and frost mitigation. The specific objectives of this research were to: • Quantify the mechanical properties of shredded tires and investigate the mechanical behavior of mixes of shredded tires with and without sand blended into the tire matrix as compared to conventional subbase and base coarse materials; • Determine the permeability of shredded tires and investigate the effect of sand on the permeability of shredded tire/sand mixes as compared to conventional granular base and subbase materials, and; • Compare the structural primary response behavior and capital cost of alternate road structures constructed with shredded tires and mixes of shredded tire and sand as a free draining subbase material compared to conventional drainage layers and road structures. The hypothesis of this research was that the mechanical behavior of shredded tire material, used as a road substructure layer, can be improved by blending it with free draining sand. It was also hypothesized that blending shredded tire with free draining sand will have improved drainage compared to conventional granular subbase and base course materials. Volumetric and mechanistic material properties and structural performance behavior of shredded tires and shredded tire/sand mixes in the mix ratios (by volume) of 1Tire:1Sand, 1Tire:2Sand and 1Tire:3Sand were evaluated and compared to City of Saskatoon subbase materials: crushed rock and granular base; as well as Saskatchewan Ministry of Highways and Infrastructure (SMHI) Type 6 subbase. Laboratory characterization showed that 100% shredded tire materials were uniformly graded indicating high amounts of voids. The addition of sand resulted in a reduction of interparticle air voids. Results from strength and stiffness characterization tests indicated that 100% shredded tires exhibited low structural stiffness, but this behavior was improved as the quantity of sand in the shredded tire was increased. The 100% shredded tire material was determined to have a dynamic modulus value of 5MPa, whereas shredded tires/sand blends at the ratios of 1Tire:1Sand, 1Tire:2Sand and 1Tire:3Sand gave dynamic moduli values of 30MPa, 110 MPa and 158MPa, respectively. For comparison, SMHI Type 6 subbase, City of Saskatoon crushed rock and granular base exhibited dynamic moduli values of 94MPa, 174MPa and 471MPa, respectively. Permeability characterization indicated that the 100% shredded tire materials were free draining at 1.42cm/s. Permeability decreased from 1.42cm/s with 100% shredded tire to 0.0026cm/s with 1Tire:3Sand. However, the shredded tire/sand mixes maintained permeability values higher than sand (0.0013cm/s). SMHI Type 6 subbase and granular materials were found to have a permeability of 0.0018cm/s and 0.000025cm/s, respectively, while crushed rock was free draining with a permeability of 1.12cm/s. Structural behavior of 100% shredded tire, shredded tire/sand mixes and City of Saskatoon subbase materials were studied in road models using a 3-D numerical road modeling software that encoded triaxial material constitutive relationships determined in this research. A typical City of Saskatoon road structure was assumed for all road structures considered in this study with varying subbase material so as to directly compare the structural effect of the shredded tire with conventional road materials under primary load limits. Modeled results of the 100% shredded tire and crushed rock roads showed peak surface deflections of 2.19mm and 0.73mm, respectively. Peak surface deflection under primary load limits was found to decrease with an increase in sand quantity within the shredded tire layer. Based on the modeling results, 1Tire:2Sand and 1Tire:3Sand yielded peak surface deflections of 1.01mm and 0.96mm, respectively. For comparative purposes, road structures with SMHI Type 6 subbase deflected at 1.14mm. Field test sections were constructed at Adolph Way in Saskatoon to compare the structural performance of shredded tire to crushed rock (currently specified by City of Saskatoon for drainage layers) in a typical residential road in Saskatoon. Unfortunately, both crushed rock (control) and shredded tire sections were found to deflect above acceptable limits due to high moisture conditions within the deep subgrade. Therefore, deeper excavation was required and the test sections were not constructed. The Adolph Way field experimentation of shredded tire showed that shredded tire road systems can be effectively constructed in the field, but showed the same sensitivity to poor subgrade conditions as crushed rock. Capital cost analysis showed the 100% shredded tire and shredded tire/sand subbase layers to be less expensive than City of Saskatoon specified crushed rock drainage layers. The 100% shredded tire layer was estimated at a total cost of $2.93/m2 while 1Tire:1Sand, 1Tire:2Sand and 1Tire:3Sand were estimated at $4.39/m2, $4.88/m2 and $5.12/m2, respectively. SMHI Type 6 subbase, crushed rock and granular base layers were estimated at a total cost of $5.85/m2, $13.95/m2 and $9.00/m2, respectively for equivalent thickness. From the structural, permeability and economic perspective of this research, the 1Tire:2Sand and 1Tire:3Sand materials proved to be cost efficient as well as technically viable options for mitigating frost action as compared with City of Saskatoon crushed rock materials evaluated. The use of shredded tire/sand mixes of 1Tire:2Sand and 1Tire:3Sand in urban local road structures with low traffic volumes are therefore recommended as a cost effective subbase drainage layer material.

Improvements in the strength and durability of frost-susceptible soils and aggregates can be achieved through chemical stabilization using portland cement, where the efficacy of cement stabilization for improving durability depends on the degree to which hydraulic conductivity is reduced. Hydraulic conductivity is commonly estimated from basic soil properties using Moulton's empirical equation. However, the hydraulic conductivity estimation does not consider the detrimental effects of freezing or the benefits of cement stabilization. The purpose of this research was to derive new equations relating hydraulic conductivity after freezing to specific material properties of cement-treated soils and aggregates stabilized with different concentrations of cement. This research included material samples from two locations in Alaska and from single locations in Minnesota, Montana, Texas, and Utah, for a total of six material samples. Each soil or aggregate type was subjected to material characterization by the Unified Soil Classification System (USCS) and the American Association of State Highway and Transportation Officials (AASHTO) classification system. Moisture-density curves were developed, and unconfined compressive strength (UCS) testing was performed to determine cement concentrations generally corresponding to low, medium, and high 7-day UCS values of 200, 400, and 600 psi, respectively. After being cured for 28 days at 100 percent relative humidity, the prepared specimens were subjected to frost conditioning and hydraulic conductivity testing. The Alaska-Elliott, Minnesota, Montana, and Utah materials exhibit decreasing hydraulic conductivity with increasing UCS, the Texas material exhibits increasing hydraulic conductivity with increasing strength from the low to medium cement concentration levels but decreasing hydraulic conductivity from the medium to high cement concentration levels, and the Alaska-Dalton material exhibits increasing hydraulic conductivity with increasing strength. Multivariable regression analyses were performed to investigate relationships between hydraulic conductivity and several material properties, including soil gradation and classification, fineness modulus, specific gravity, cement content, porosity, compaction method, dry density, and 7-day UCS for each specimen. The R2 values computed for the six-parameter, four-parameter, USCS, and AASHTO-classification models are 0.795, 0.767, 0.930, and 0.782, respectively. Further research is recommended to investigate the effects of cement on hydraulic conductivity for USCS and AASHTO soil types not covered in this research.

L'objectif de ce travail est de mettre en exergue les avantages et les inconvénients d'introduire des microfibres végétales, issues du recyclage du carton, dans les bétons autoplaçants BAP, et plus précisément leur influence sur la durabilité aux cycles gel-dégel. Une méthodologie expérimentale a été mise en place pour la formulation des BAP fibrés devant répondre aux exigences suivantes : classe d'exposition XF2, classe de consistance de type Dmoy=68±2 cm. Elle repose sur la théorie de la compacité maximale pour le dosage des particules solides et sur la méthode du mortier de béton équivalent, MBE, pour le dosage en adjuvants. En partant de la composition du BAP de référence, les microfibres végétales ont été introduites à six pourcentages volumiques distincts par rapport au volume du ciment. Une campagne d'essais expérimentaux réalisée sur les MBE fibrés, a montré que l'introduction des microfibres à un dosage compris entre 21% et 41% améliore leurs propriétés physiques et mécaniques. A l'échelle des BAP, les résultats expérimentaux ont montré que les BAP fibrés aux dosages précédents, BAPF 21% et BAPF 41%, possèdent une porosité et une perméabilité plus faibles que le BAP de référence et par conséquent des caractéristiques mécaniques plus élevées. La résistance au gel-dégel des bétons autoplaçants, BAP de référence, BAPF 21% et BAP formulé avec un entraîneur d'air ainsi que de deux bétons vibrés le premier de référence et second contenant 15% en volume du ciment des microfibres, a été étudiée en soumettant ces bétons à des cycles gel-dégel selon la norme NF P18-425. Les résultats obtenus montrent que les bétons additionnés des microfibres végétales sont plus sensibles aux cycles gel-dégel. L'effet nocif des microfibres s'explique par leur nature hydrophile associée à une faible perméabilité des bétons additionnés. De plus, le rôle des granulats sur la sensibilité à l'action du froid a été discuté. Il a été conclu que les granulats silico-calcaires poreux et fragiles sont à éviter dans les bétons destinés aux environnements gélifs. / The aim of this work is to emphasize the advantages and disadvantages of introducing vegetable based microfibers, resulting from cardboard recycling, in self compacting concrete SCC, and especially their influence on the frost durability. An experimental methodology has been developed for SCC formulation based on following requirements: class of environmental exposure XF2, slump flow Dmoy = 68 ± 2 cm. It is based also on the maximum packing theory for the determination of solid particles content and the method of concrete equivalent mortar, CEM, for superplasticizer dosage. Starting from the SCC of reference composition, vegetable based microfibers were introduced at six different volumetric percentages related to cement volume. A campaign of experimental tests performed on fibred CEM showed that the introduction of microfibers at a volumetric dosage between 21% and 41% improved physical and mechanical properties. On the SCC scale, the experimental results have shown that fibred SCC at previous dosages, FSCC 21% and FSCC 41%, have porosity and permeability lower than the SCC of reference and consequently higher mechanical properties. Frost resistance of , SCC of reference, FSCC 21% and a SCC formulated with an air-entraining as well as two vibrated concretes, the first of reference and second containing 15% microfibers by volume of cement, was studied by subjecting them to freeze-thaw cycles according to NF P18-425. The results show that microfibers added concretes are more susceptible to frost damage. The harmful effect of vegetable based microfibers is explained by their hydrophilic nature associated to a low permeability of fibred concrete. Furthermore, the role of aggregates on the frost sensitivity was discussed. It was concluded that the porous and fragile lime aggregates should be avoided in concrete intended for cold climate.

No description available.

Phase change of the water in the soil skeleton under cold climate conditions (also known as frost action in soils) affects soil properties and can be responsible for serious alterations in a soil body; causing damages (due to the volumetric expansion known as frost heave) to structures on or below the ground surface such as foundations, roads, railways, retaining walls and pipelines, etc. In order to improve the current design methods for roads against frost action, the Swedish Transport Administration (Trafikverket) has initiated a research program. The main goals of the program are to revise the existing frost heave estimation methods and improve the frost susceptibility classification system for subgrade soils. Literature was reviewed to gather the details of different freezing test equipment around the world and to identify common trends and practices for laboratory freezing tests. Based on the literature review and the collaboration with the University of Oulu, Finland an experimental apparatus was assembled for studying frost action in the laboratory. A detailed description of the experimental apparatus is given. Top to down freezing of specimens (of 10cm height and diameter) can be monitored while keeping track of water intake, vertical displacements (heave) and the temperature profile within the sample. Loads can be applied at the top of the sample to study the effects of overburden. Moreover, the test setup was modified with a camera system to have the option of recording the experiments. Disturbed samples of two different soil types were tested. Experiments with fixed and varying temperature boundary conditions were conducted to assess the validity of the assumptions for the frost heave estimation methods currently in use in Sweden. To this end, a qualitative relationship between frost heave and heat extraction rates based on theoretical equations was established. It was shown that there is a significant difference between the preliminary findings of the experimental work and the current system being used in Sweden to quantify heave. Image analysis techniques were used on two experiments that were recorded by the camera system. Image recording and correlation analyses provided detailed information about frost front penetration and ice lens formation(s) under varying temperature boundary conditions. Thawing has also been regarded in further studies. Results of the image analyses were compared to readings from conventional displacement measurements during the same test. Significant agreement between the results of image analyses and displacement measurements has been found. Image analysis was shown to be a viable method in further understanding of frost heave mechanisms. Shortcomings and disadvantages of utilizing the theoretical equations as well as the image analysis techniques were discussed. Potential remedies for overcoming the drawbacks associated with each approach are suggested. The work is concluded by discussing the potential improvements, planned upgrades (addition of pore pressure transducers) and the future experiments to be conducted.

Phase change of the water in the soil skeleton under cold climate conditions (also known as frost action in soils) affects soil properties and can be responsible for serious alterations in a soil body; causing damages (due to the volumetric expansion known as frost heave) to structures on or below the ground surface such as foundations, roads, railways, retaining walls and pipelines, etc. In order to improve the current design methods for roads against frost action, the Swedish Transport Administration (Trafikverket) has initiated a research program. The main goals of the program are to revise the existing frost heave estimation methods and improve the frost susceptibility classification system for subgrade soils. Literature was reviewed to gather the details of different freezing test equipment around the world and to identify common trends and practices for laboratory freezing tests. Based on the literature review and the collaboration with the University of Oulu, Finland an experimental apparatus was assembled for studying frost action in the laboratory. A detailed description of the experimental apparatus is given. Top to down freezing of specimens (of 10cm height and diameter) can be monitored while keeping track of water intake, vertical displacements (heave) and the temperature profile within the sample. Loads can be applied at the top of the sample to study the effects of overburden. Moreover, the test setup was modified with a camera system to have the option of recording the experiments. Disturbed samples of two different soil types were tested. Experiments with fixed and varying temperature boundary conditions were conducted to assess the validity of the assumptions for the frost heave estimation methods currently in use in Sweden. To this end, a qualitative relationship between frost heave and heat extraction rates based on theoretical equations was established. It was shown that there is a significant difference between the preliminary findings of the experimental work and the current system being used in Sweden to quantify heave. Image analysis techniques were used on two experiments that were recorded by the camera system. Image recording and correlation analyses provided detailed information about frost front penetration and ice lens formation(s) under varying temperature boundary conditions. Thawing has also been regarded in further studies. Results of the image analyses were compared to readings from conventional displacement measurements during the same test. Significant agreement between the results of image analyses and displacement measurements has been found. Image analysis was shown to be a viable method in further understanding of frost heave mechanisms. Shortcomings and disadvantages of utilizing the theoretical equations as well as the image analysis techniques were discussed. Potential remedies for overcoming the drawbacks associated with each approach are suggested. The work is concluded by discussing the potential improvements, planned upgrades (addition of pore pressure transducers) and the future experiments to be conducted. / Modellering av tjällossningsförlopp vid vägdimensionering

The effects of frost action introduce many challenges in the design and construction of roadways in cold regions throughout the United States. The penetration of frost into pavement structures can lead to differential frost heave during winter and thaw weakening during spring. Both of these damage mechanisms lead to premature pavement distress, structural deterioration, and poor ride quality. Because the availability of naturally occurring non-frost-susceptible pavement base materials is rapidly diminishing in many areas while project budgets remain largely inadequate, pavement engineers are utilizing alternative materials and techniques to minimize such damage. The purpose of this research was to investigate and document the state of the practice concerning the design and construction of pavements in cold regions. In particular, the various methods and standards employed for characterizing materials, improving soils and aggregates, and determining pavement layer thicknesses were explored. A comprehensive literature review was performed, and a questionnaire survey was conducted of various state DOTs throughout the United States that are involved with the design and maintenance of roadways. The study was directed primarily at identifying practices utilized by state DOTs in climates with freezing temperatures. The information obtained in this research represents a unique compilation of standards of practice that have been developed by DOTs based on years of experience and research in their respective jurisdictions. While this research allows engineers at state DOTs to compare their pavement design and construction practices with those of other states represented in the survey, consulting engineers and engineers in local governments involved in characterizing materials, improving soils and aggregates, and determining pavement layer thicknesses can also benefit from this work.

From the Proceedings of the 1971 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 22-23, 1971, Tempe, Arizona / The importance of pine forest as a timber and water producing area has led to intensive management, including protection from wildfire. This has resulted in dense stand growth with increased destructive fire potential and transpirational water loss. In Arizona, as in many areas, prescribed forest burning has been used to effectively reduce these fuel hazards. Some question has arisen about the possible side effects of such treatments, particularly air pollution and reduction of infiltration and water yield. In an effort to determine the effects on infiltration, plots receiving various treatments (control, light burn, heavy burn) were fitted with fusion pyrometers before burning, to measure soil surface temperatures during burning. After burning, infiltrometers were installed. Surface temperatures did not exceed 200 degrees f. For the light burns, and ranged over 350-500 degrees f. During heavy burns. Both heavy and light burns produced highly significant decreases in infiltration capacities after burning and the surface 2 inches showed increases in soil pH, carbon and total nitrogen percentages. Infiltration capacities returned to normal after overwintering and were attributed to frost action on soil texture and porosity. The soil chemical changes decreased slowly over 2 years. Soil water repellency also increased and the significance of this is discussed.