1. EXECUTIVE SUMMARY

   The Queen's University entry to the 2000 Canadian National concrete Canoe Competition is Quixote, a high performance, exhaustively researched, and very attractive boat. Quixote embodies the heart, soul and dedication of the Queen's Concrete Canoe Team. It has an asymmetrical hull 5500 mm (18 ft) long, 870 mm (34 in) wide at the widest point, and 270 mm (10.6 in) deep. The hull thickness varies from six to eight millimetres (0.24 to 0.31 in). The mass of the canoe is 52 kg (115 pounds), and it is finished in a stunning blend of yellow, red and blue - the traditional Queen's Tricolour.

   The 2000 Canadian National Concrete Canoe Competition marks a significant point in the development of the Queen's concrete Canoe Team (QCCT). The culmination of four years of experimentation, trials, tribulations, successes and failures has developed a well balanced, durable, attractive and fast canoe capable of challenging the best in the world. This year saw the advent of significant breakthroughs in construction technique (a vacuum de-watering and finishing system) and research work for both concrete mix design and reinforcement. These breakthroughs, coupled with the enthusiasm and spirit Queen's engineers are renowned for should carry the QCCT to victory in Canada.

   2. INTRODUCTION

   In 1841, twenty-six years before Confederation, Queen Victoria issued a Royal Charter for a Queen’s College at Kingston. Though established primarily to train the clergy, the small denominational college became Queen’s University at Kingston when the Canadian Parliament amended the charter in 1912 separating the church from the university.

   Queen’s 65 hectare (160-acre) campus is set on the north east shore of Lake Ontario in Canada’s historic "Limestone City", Kingston. The city was founded in 1673 and has been shaped by a powerful sense of geography. It’s strategic location, at the southernmost end of the Rideau Canal where Lake Ontario feeds into the St. Lawrence River, provided prosperity through shipbuilding and national defense during the 1800’s. Kingston was the first capital of colonial Canada before the National Seat of Government was moved to Ottawa.

   Of the more than 17 650 students enrolled at Queen’s University, 1755 are registered with the Faculty of Applied Science. Approximately 180 individuals are studying civil engineering, seventeen of which are member of the Queen's Concrete Canoe Team. In recent years, the Team has consisted mainly of civil engineering students. This year, students from engineering physics, chemical and mechanical engineering have contributed greatly to the development of Quixote, this year’s NCCC entry.

   The Team has christened its canoe "Quixote" after Don Quixote de la Mancha, the hero of Miguel de Cervantes’ infamous tale. Though originally published in 1605, the story is timeless as it reflects the anti-individualism still existing today. Quixote is ridiculed for his seemingly pointless mission to "make a knight-errant of himself, roaming the world over in full armour and on horseback in search of adventures." (REF) Like Quixote, the Team is often mocked for the tremendous effort invested into the research, design and construction of the concrete canoe. The Team's response to such chastising is simple. As Don Quixote did, the Team is "in search of adventures."

   Queen’s began concrete canoe racing in 1976. Though Queen’s participated in the competition the following year, it did not participate in its third competition until 1997, when a group of students from Arnprior decided to resurrect the team. Although they placed sixth overall, their concrete mixture and technical report placed among the top three teams. Improvement to the design enabled Queen’s to clinch fourth place overall in 1998, where we received an award for best oral presentation. Last year was our best competition yet, having placed third overall and winning the spirit award. Our goal for the 2000 CNCCC is to win the competition outright and represent Canada at the concrete canoe competition in Colorado.

2. HULL DESIGN

Quixote is the product of an extensive and methodical hull design process. The principles used in the design stem from classic naval architecture methods with specific applications for canoe design. Quixote’s hull form is an original design developed by the members of the QCCT.

General

Our three years of competition experience has provided us with a wealth of knowledge in the construction and shaping of concrete canoe hulls. There are a few "tricks of the trade" which must be kept in mind when designing a hull made of concrete. Firstly, tensile stresses should be minimized in order to reduce cracking in the hull. This prevents damage to the canoe’s finish, and decreases the likelihood of water infiltration. However, for the reinforcement to develop its full strength the hull must crack to some degree. Secondly, if the composite section has orthotropic properties, such as higher bending strength in one direction, the material should be oriented in the direction of the dominant stress to maximize the hull strength.

Quixote

Following the conclusion of the 1999 Canadian Concrete Canoe Competition the design process for the 2000 canoe began. The QCCT was pleased with the performance of its 1999 entry, Krakatoa, who's third-place finish had prompted team members to review the current design to determine how the hull could be modified to improve the canoe’s performance. The consensus was that a longer, finer hull would reduce drag and increase the theoretical hull speed. It was thought that modifying the profile of the canoe to a more hydrodynamic shape by increasing the concavity of the stern would promote laminar flow over a longer portion of the canoe hull and reduce form drag.

In the fall, the QCCT conducted a cost-benefit analysis to determine the most cost-effective way of producing a competitive concrete canoe. It was decided that the polystyrene foam mold used to produce Krakatoa 1999 would be re-used by reshaping the form as per Quixote’s specifications. This produced a set of geometric constraints, as mold dimensions could be decreased with ease, but increasing the width or depth of the existing form would be difficult.

Table XX: Design Constraints

These constraints were considered in the evaluation of the new hull shape.

Modifications to the cross-section incorporated the following points; a steeper vee bottom to produce better straight line tracking; soft chines to reduce drag as much as possible and promote good secondary stability; and finally a profile just above the waterline on both sides of the canoe that would increase the rocker of the hull when heeled over, thus making it easier to turn.

With these concepts in mind, and full of enthusiasm, the design team began the process of producing the plan for the hull. Initial work was completed with the use of three-dimensional computer modelling, to allow changes to the hull profile to be analysed. The computer system was also used to analyze the stresses on the hull after the design was finalized. When the hull shape had characteristics that the team was happy with, a one tenth scale model was produced using basswood. This model was tank tested to determine its relative merits with other models available at the same scale. The Team has amassed a large collection of these models over the past years. The hull shape was slightly modified based on the results of these tests, and the test results show that the design produced has the lowest drag of any hull considered by the team over the past three years. (INSERT DRAG CHART HERE)

At this point, the Team began the process of analysing the hull shape to determine the maximum stresses on the hull. The following conditions were examined, supported at both extreme ends (upright and inverted, corresponding to being carried from place to place by two people), supported in the water carrying both two and four paddlers, and finally inverted, supported on two interior points and subject to lateral wind loading of 120 km/h, which corresponds to the worst case transportation loading experienced by the Team in the past. Dynamic loading due to self weight and bouncing was also considered (heavy hits of bumps on highways). Unsurprisingly, the worst case stresses were due to transportation loading. This analysis determined that the maximum elastic stress that would be developed in the hull would be 15 Mpa. This information was incorporated into both the concrete mix design research and the reinforcement research.

3. 3. Final Hull Shape

The final hull design arrived at by the Team is an asymetrical hull shape, of maximum width 870 mm and overall length 5500 mm. The depth is 270 mm to give generous freeboard and allow for choppy on-water conditions. The hull has a pronounced shallow vee bottom, soft chines and a gentle flare. The bow and stern are rockered slightly to allow quick turning, and the rocker becomes more pronounced as the angle of heel increases. A fifty millimetre gunwale is monolithic with the hull to increase the stiffness of the boat. Flotation chambers filled with polystyrene foam take up the front and rear 570 mm of the hull. The widest point is located 3000 mm from the bow, and from that point the hull quickly tapers to a concave stern.

1. CONCRETE MIXTURE DESIGN

The Team recognized early in the campaign to build Quixote that a systematic approach to developing a concrete mix was necessary. The structural system chosen for Quixote required a high strength concrete with a low density to reduce the weight of the canoe and increase performance. A very low permeability concrete was also desirable to prevent weight gain due to water exposure on the unpainted band on the canoe. The hull design called for a minimum strength of 25 Mpa, and a density of less than 1300 kg/m³.

The teams' goal was to produce such a high performance concrete, but this could not be achieved by applying the conventional theory and practice for lightweight concrete. For this reason, the Team decided to investigate the behaviour of concrete mixes based on the following theory. Concrete strength is generally assumed to be dependent on the density and stiffness of the concrete, and the quality of the cement paste is a major determining factor in developing the strength of a mix. The team decided an ideal mix would be one in which the cement paste was as dense and impermeable as possible, while the aggregate in the concrete had high strength, low density and very low permeability. This approach differs from the usual method where a low strength, highly porous aggregate is used to produce low density, low strength concrete.

The Team decided to conduct background research to develop the above theory to the point that it could be used to predict the properties of a mix design. To this end, 35 research mixes were created to investigate the effects of water/cement ratio, varying silica fume content in total binding material, cement/aggregate ratio, and effects of different aggregates on both strength and density. The results from these tests were used as background to design five trial batches for the final mix design. The results from these tests are presented in the following conclusions. All though the research is not totally definitive in that more samples would be required to achieve statistically accurate design guidelines, they are certainly suitable for the purpose at hand.

Table ### Concrete Mix Guidelines

Concrete strength and density were evaluated using the procedures of ASTM ####(REF), generally used for evaluating the compressive strength of cement based grout. The general procedure used for this test was to cast 51 mm (2 in) cubes of the test concrete, cure them in a fog room for seven days and test them in compression. All strength results quoted in this report are based on seven day strengths. The results of this test were found to correlate very well with the results of tests using the procedures of CSA A23.2-9C, Compressive Strength of Cylindrical Concrete Specimens(REF). This non-traditional test was done to speed the feedback cycle to the concrete mix design team and to economise the use of scarce resources.

Additional testing on the concrete used to cast the canoe was done using both CSA A23.2-9C, ASTM C 469 - 94, Standard Test Method for Static Modulus of Elasticity and Poisson's Ratio of Concrete in Compression(REF), and CSA A23.2-13C, Splitting Tensile Strength of Cylindrical Concrete Specimens(REF).

Composite Section

Standardized composite sections have been tested by the Team for the past three years. The standard plate is 4 inches wide, 14 inches long and 1/4 inch thick. Various combinations of reinforcing are placed in the forms and concreted, and the test method used by the team involves manual loading the plate with a single line load at midspan, while recording deflections if necessary using a dial gauge indicator. The final concrete mix chosen for its compressive strength and density was used in all composite section tests. The results of this testing are presented in the Reinforcement section.

3. REINFORCEMENT
4. As the structural system chosen for Quixote required a thin, relatively rigid composite wall, and the construction of the hull required a flexible reinforcement, the choices for reinforcing material were constrained by the following requirements. The material should have a thickness of less than 1.5 mm, have a modulus of elasticity greater than 100000 Mpa, yet be ductile and flexible enough to conform to the mold while retaining integrity. These somewhat incompatible conditions led to the choice of galvanized steel wire mesh as the reinforcing system.

   While composite materials such as carbon fibre, aramids and other plastics have become more available in recent years, steel is a very cost competitive material, and has additional benefits with respect to the rules of the competition. The high modulus of elasticity of steel means that smaller cross-section of steel can carry similar loads to larger sections of composites. Most fibre reinforced polymers tend to have brittle behaviour near failure, while steel is capable of yielding to a new shape while retaining a useful amount of strength. A further attractive feature of steel is that it can be easily cut and shaped with available tools, requires no special protective equipment and in general has very isotropic behaviour. Steel has an unmatched stiffness, and that is of paramount importance when dealing with composite sections as called for by the hull design. Finally, steel mesh is available in a wide range of wire gauges, mesh sizes, weaves and coatings.

   Extensive comparison of the properties of steel mesh led to the testing of various sizes of mesh conforming to the guidelines of ASTM A 740 - 96 Standard Specifications for Hardware Cloth. The meshes chosen were square welded wire, hot dip galvanized and were of two sizes - 6.35 mm (0.25 in) and 12.7 mm (0.5 in). These materials were tested in tension for the ultimate strength. The procedure used to test the materials was a variation on ASTM E 8, Standard Test Methods of Tension Testing of Metallic Materials. Specimens were produced using reduced cross-sections over a gauge length three times as long as the width. The samples were placed in specially prepared wedge-type grips and tightened in place with a torque wrench to ensure uniform gripping pressure between all tests. The samples were then installed in the testing machine and loaded until failure. The failure loads were recorded, and the strengths in load per unit width were determined. All test specimens failed at connection points where welding had taken place.

   The thicknesses of the reinforcement layers were found following the procedure outlined in the official concrete canoe rules.

   Composite section tests were used to evaluate the strength, ease of placement and density of the various reinforcement combinations considered for Quixote. In all, sixteen composite sections were tested in preparation for choosing the reinforcement, as well as an additional twenty nine identical sections from the previous year that were used to provide baseline data. This large bank of knowledge allowed the Team to fine tune the reinforcement used to the stress levels in the different parts of the hull. Plots of bending strength against mass per unit area are shown in Figure XX. While the highest absolute strength reinforcement combinations were not chosen, the selected combinations had outstanding performance to weight ratios, and exhibited good constructability and finishing properties.

   

5. CONSTRUCTION
6. Introduction

   The success of the previous year's construction method, DASCHUNT 2.1 (Differential Axial Sandwich Construction Technique, Version 2.1) was considered greatly during the development of the techniques used to build Quixote. The cost-benefit analysis carried out by the Team indicated that reuse of the polystyrene foam mold would have the greatest benefit to the Team, while carrying the least cost. It follows that the technique used would be very similar to previous year's. Other options considered in the analysis were a female mold, or producing a two part mold (both inside and outside surfaces produced). These latter two options were dismissed for the following reasons: A female mold would make stretching the reinforcement tightly to the mold surface difficult, and thus make control of hull thickness difficult. A two part mold, while having distinct advantages, would again be difficult to produce with the resources of the Team, and any variations in dimensions between the two molds would lead to localized areas of thin or thick spots. It was decided that a male mold composed of 51 mm thick polystyrene foam sections would give the best performance. As the Team had an oversized mold available, construction went very quickly.

   To quickly describe DASCHUNT 2.1, it involves the following steps. First, sections of the three dimensional canoe model are taken and plotted full size. These are used to produce cross-section shaped pieces of polystyrene foam, that are then glued together and aligned using a notch cut out of the base. These sandwiches are then sanded smooth according to the plans produced, covered in shrink wrap plastic and are ready for the concrete pour. By starting with a pre-existing mold, a great amount of labour and expense was saved.

   The existing sytrofoam mold was reshaped according to the plotted cross-sections, and the extreme ends of the mold were rebuilt to the new shape. When the foam was as smooth as possible, a gypsum based drywall joint compound was used to fair the mold to a perfectly smooth surface. Plastic shrink wrap was again used to seal the mold and prevent the concrete from adhering. This created a built in mold release layer.

   Prior to the final application of shrink wrap, the layers of reinforcement were cut to fit the hull shape and set aside. The initial layer of concrete was hand applied to the mold, the innermost layer of reinforcement was applied to the concrete. Further layers of concrete and reinforcement were then alternated until the final surface layer was in place. At this time, trowelling of the concrete surface began, to remove any large surface imperfections. The vacuum de-watering system was then used over individual sections of the hull, working from one end of the boat to the other. This system compressed the concrete beneath the area being de-watered, and also smoothed the surface to a great degree, thus producing an excellent finish and ensuring that there would be few if any air voids in the concrete. After the vacuum system had finished, the surface was re-trowelled to remove any remaining imperfections, and a polyethylene sheet was used to cover the hull.

   A vaporisor was used to provide a 100% relative humidity environment beneath the polyethylene sheet, and this was maintained for 40 hours, when the hull was removed from the mold. The hull was again sealed inside the plastic, and left to cure in the 100% humidity environment for 10 days. At this time the protruding gunwales were cast in place after the reinforcement left exposed for this purpose was bent to shape. After a further seven days of curing, the plastic was removed and the vaporisor shut off. At this point the Team began sanding the outer surface of the hull to prepare for painting. Any small hollows at this stage were filled using a special low density cement and microsphere fairing compound. This compound is not expected to contribute any strength to the hull, and is only in place for aesthetic reasons. When the surface is as smooth as practical, the hull is primed and then painted using a base coat – clear coat automotive paint system. This produced the final product.

7. PROJECT MANAGEMENT
8. The team’s organizational style has made substantial improvements and advances from previous years. This year, the team has organized itself into two main groups: research and construction. Each group would be responsible for carrying out various tasks under the direction of two co-captains. The older and more experienced captain led the research team in search of innovative features and improvements to the canoe, while the younger and less experienced one acted as project manager to provide planning and organization for the various stages of canoe construction. Both captains work together to define the overall goals and ensure the progress of the team.

   In order to divide the tasks equally amongst the two groups of members, positions were assigned according to experience and capability. Such positions include materials specialist, concrete mix designer, construction manager, treasurer, communicator, and fundraiser. Biweekly meetings were held to ensure effective communication and exchange of information between the two groups. At the same time, opinions are voiced and decisions made.

   This year marks the transition year in which new, unskillful members emerge and old, knowledgeable members depart. To successfully pass on the torch, a good project planning and team structure has been implemented to ensure the success of the Queen’s Concrete Canoe Team in the future.

9. COST ASSESSMENT
10. The total cost to build Quixote is calculated based on the methods and rates established in Section III.E-F of the rules. From the beginning to the end of the project, time and money spent on the canoe were carefully recorded. They are broken into three phases: research and development, construction, and competition.

    The majority of the expenses belong to labour cost. Each phase of the project is divided into sub-categories in which the hours spent by each member are recorded. As shown in Table XXX below, the hours spent on construction phase is the greatest, and therefore, accounts for the largest labour expenses. . In addition, an outside consultant was hired for a cost $600. The total hours spent for each phase is multiplied by the Direct Labour Rates (DLR) for each team member and summed to obtain a total labour cost of $40,255.75. (See Appendix XXX, Table XXX for Billable Direct Labour Rates)

    The rest of the expenses comprise of construction and project materials. Reinforcement and painting costs are high as compared to other costs such as concrete materials. This is due to generous sponsorship from the Civil Engineering Department at Queen’s. In project expenses, major costs include display, race equipment, and T-shirts. The total costs are again summed up and multiplied by a markup of ten percent to reach a total cost of $3,623.39.

    Table XXX below shows the summary of costs involved in the construction of Quixote. For more detailed cost breakdown, see Table XXX in Appendix XXX.

    Table XXX Summary of Costs

    Category	Hours	Labour Cost	Material Cost	Total
    Research and Development	191	$14,702.75	$103.39	$14,806.14
    Construction	277	$19,279.75	$1,045.00	$20,324.75
    Competition	104	$6,273.25	$2,475.00	$8,748.25
    Total	572	$40,255.75	$3623.39	$43,879.14

11. INNOVATIVE FEATURES

The 1999-2000 academic year was a breakthrough year for the Queen's Concrete Canoe Team. Since a great deal of labour was saved by reshaping the mold from 1998-1999, the Team's energy and effort was spent in more in depth research for concrete mix design, construction technique and in a highly original method of finishing the canoe.

1. 1. Concrete Research
   2. Beginning with the concrete mix design research, the Team realized that published guidelines on lightweight concrete mix design did not include the methods and materials most useful for the high performance low-density concrete desired for the structural system. Established sources (fn) using typical lightweight aggregate claim that strength and low density are incompatible. It has been the Team's experience that it is quite possible to produce concrete with density below 1200 kg/m³ while maintaining strength above 30 MPa. It was apparent that if we wished to systematically design our mix, we would need to develop our own guidelines for the effects of the various parameters that influence concrete strength and density. To this end, the large number of trial mixes produced were all tailored to investigate the effects of individual variables, rather than attempting to jump to the final mix design at once. This approach has the added benefit of informing future teams of the behaviour of concrete mixes utilizing the ingredients investigated here. A set of design guidelines was produced to accurately predict the strength and density of the final mix, and comparatively few final trial mixes were produced.
   3. Construction and Finishing
   4. The most significant innovation of the 1999-2000 Team is about to be described. It falls mainly in the category of finishing, although its application has effects on concrete mix design and other construction methods. For the first time, after several years of thought, the Team has developed and used a vacuum de-watering system for final finishing of the canoe. The theory and the application of this system will be described in the following paragraphs.
      1. Theory
      2. Applying a vacuum to the surface of freshly placed concrete causes mix water to be removed from the concrete, lowering the effective water/cement ratio. This action also has the effect of consolidating the fresh concrete through the application of atmospheric pressure on the flexible vacuum membrane. This two-fold effect causes an increase in the strength, durability and degree of impermeability of the concrete. Tests conducted during the development of the system show an increase in bending strength of a composite section of 24 %. Beneficial side effects are the increased uniformity of the surface finish (with respect to hand troweled concrete), and the speed with which vacuum processed concrete can be removed from the form. It should be noted at this time that due to losses in the system it is impossible to accurately determine the amount of water removed, and thus the new water/cement ratio.
      3. Application
      4. Densely woven cotton filter cloth is placed directly on the surface of the fresh concrete. This filter allows the passage of water but stops the movement of other concrete constituents. A heavy vinyl sheet is then placed above the cotton filter. This sheet is larger than the filter to allow a seal to be developed between the vinyl and the fresh concrete. A vacuum pump is attached to the vinyl sheet, and the air beneath the vinyl is removed from the system to create the low pressure environment necessary to remove the water. The system used by the Team reduces the pressure to approximately 1/8 atmosphere, or 87.8 kPa (26 in Hg) below ambient conditions. This low pressure is maintained for approximately 20 minutes for each section of the hull being processed. Processing the entire canoe in this fashion takes approximately 240 minutes.
      5. Effects

The vacuum de-watered concrete resulted in an increase of bending strength of 24 percent. The compressive action caused all reinforcement to be pressed beneath the surface of the concrete, resulting in a much more uniform appearance. The surface of the processed concrete was hardened immediately, and could be touched up to allow instant repair of any imperfections. The consolidating action caused most air voids to be removed throughout the thickness of the canoe wall. The vacuum de-watering system has proved to be a highly effective and useful tool in preparing a concrete canoe hull.

8. SUMMARY