ACI-SP-181-1998.pdf
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1、Copyright American Concrete Institute Provided by IHS under license with ACI Licensee=IHS Employees/1111111001, User=listmgr, listmgr Not for Resale, 03/05/2007 19:10:40 MSTNo reproduction or networking permitted without license from IHS -,-,- STD-AC1 SP-LAI-ENGL 1777 Obb2949 05q35L17 Obb I Recent D
2、evelopments in the Design and Specification of Concrete Pavement Systems Editor D. G. Zollinger SP-181 international” Copyright American Concrete Institute Provided by IHS under license with ACI Licensee=IHS Employees/1111111001, User=listmgr, listmgr Not for Resale, 03/05/2007 19:10:40 MSTNo reprod
3、uction or networking permitted without license from IHS -,-,- STD-AC1 SP-LL-ENGL 1999 I Obb2749 0.543550 888 DISCUSSION of individual papers in this symposium may be submitted in accordance with general requirements of the AC1 Publication Policy to AC1 headquarters at the address given below. Closin
4、g date for submission of discussion is June 1, 1999. All discussion approved by the Technical Activities Committee along with closing remarks by the authors will be published in the SeptemberlOctober 1999 issue of either AC1 Structural Journal or Denver, Colorado; and Atlanta, Georgia, and sponsored
5、 by AC1 Committees 325, Concrete Pavements, and 214, Evaluation of Results of Tests Used to Determine the Strength of Concrete. It is anticipated that future esign development will most notably center on the use of mechanistic concepts, and utilize important material properties that affect the perfo
6、rmance of concrete pavement structures. The papers in this publication address many different aspects of mechanistic design, such as environmental stress, improved pavement design methodology, approaches to performance-based specification, characterization of joint sealants for design purposes, char
7、acterization of concrete strength based on fracture properties, and others. The discussions presented in these papers should provide an avenue by which advancements in the critical areas of pavement design can be made possible for improved future design applications. Editor D. . Zollinger Copyright
8、American Concrete Institute Provided by IHS under license with ACI Licensee=IHS Employees/1111111001, User=listmgr, listmgr Not for Resale, 03/05/2007 19:10:40 MSTNo reproduction or networking permitted without license from IHS -,-,- STD-AC1 SP-LL-ENGL 1449 Obb2749 0543552 b50 = CONTENTS THERMAL STR
9、ESSES IN SQUARE SHAPED CONCRETE PAVEMENTS by J. Silfwerbrand 1 IMPROVED CONCRETE PAVEMENT DESIGN METHODOLOGY FOR BETTER PERFORMANCE by E. Owusu-Antwi and M. Darter 17 FACTORS AFFECTING LOAD TRANSFER ACROSS TRANSVERSE JOINTS IN JOINTED CONCRETE PAVEMENTS by N. Buch . 43 EFFECTS OF AGE AND DEFORMATION
10、 ON VISCOELASTIC BEHAVIOR OF CONCRETE JOINT SEALANT by A. Gurjar and T. Tang . 65 RECENT DEVELOPMENTS IN STRENGTH TESTING FOR CONCRETE PAVEMENT CONSTRUCTION by J. Soares, D. Zollinger, and T. Tang 87 DEVELOPING 2 1 st CENTURY SPECIFICATIONS FOR PORTLAND CEMENT CONCRETE PAVEMENTS by S. Grater, E McCu
11、llough, and D. Zollinger . 11 1 V Copyright American Concrete Institute Provided by IHS under license with ACI Licensee=IHS Employees/1111111001, User=listmgr, listmgr Not for Resale, 03/05/2007 19:10:40 MSTNo reproduction or networking permitted without license from IHS -,-,- Thermal Stresses in Sq
12、uare Shaped Concrete Pavements by J. Silfwerbrand Svnoiisis: Thermal stresses in concrete pavements might be calculated according to a procedure developed by professor J. Eisenmann. The thermal stresses are dependent on the subgrade stiffness. Soft subgrades result in lower stresses. The Eisenmann p
13、rocedure has been developed to cover square shaped slabs. This procedure is presented in this paper. Two calculation examples are also presented and discussed. Keywords: Concrete pavements; square slabs; thermal stresses 1 Copyright American Concrete Institute Provided by IHS under license with ACI
14、Licensee=IHS Employees/1111111001, User=listmgr, listmgr Not for Resale, 03/05/2007 19:10:40 MSTNo reproduction or networking permitted without license from IHS -,-,- STD-AC1 SP-LBL-ENGL 1999 W Obb291i 0543554 423 W 2 Silfwerbrand AC1 member Johan Silfwerbrand is currently associate professor at the
15、 Dept. of Structural Engineering at the Royal Institute of Technology in Stockholm, Sweden. He received his Ph.D. in Civil Engineering from the Royal Institute of Technology in 1987. His research interests are in repair, creep and shrinkage, pavements, overlays, and steel fibre reinforced concrete s
16、tructures. He is a consulting member of AC1 Committee 342, Evaluation of Concrete Bridges and Bridge Elements, a consulting member of AC1 Committee 345, Bridge Construction and Maintenance, and an associate member of 546, Repair. He is also active in CEB and RILEM committees. 1. INTRODUCTION Concret
17、e pavements are designed for traffic and thermal stresses. In Sweden, the thermal stresses have been calculated according to professor J. Eisenmann. He bases his calculations on an effective span length. In the calculation of the effective span length, he considers the effect of the subgrade reactio
18、n using a beam element. Soft subgrades shorten the effective span length and, hence, reduce the thermal stresses. The procedure has been used to calculate thermal stresses under Swedish conditions in highway pavements, industrial pavements, and pavements in tunnels2-4. The temperature distribution i
19、n a concrete pavement can approximately be divided into two parts: (a) a uniform part and (b) a temperature gradient (Fig. 1). The uniform temperature distribution does not cause any major temperature stresses in jointed concrete pavement because the pavement is practically free to move horizontally
20、 at the joints. The temperature gradient causes curling or warping and - if the curling is restrained - thermal stresses. Hence, the immediate cause of the stresses is not the temperature, but the dead load that counteracts the curling tendency of the pavement. During a warm summer day, the top surf
21、ace of the pavement is heated more than the bottom surface. A positive temperature gradient develops. The pavement slab curls with the central point moving upwards. The dead load of the pavement counteracts the curling and causes flexural tensile stresses in the bottom of the pavement (Fig. 2, left)
22、. During the night, the top surface gets cool more rapidly than the bottom surface. A negative temperature gradient develops and the pavement slab edges move upwards. In this case, the dead load causes flexural tensile stresses at the top of the slab (Fig. 2, right). Traffic loading causes flexural
23、tensile stresses in the bottom of the slab, i.e., in the same part of the slab Copyright American Concrete Institute Provided by IHS under license with ACI Licensee=IHS Employees/1111111001, User=listmgr, listmgr Not for Resale, 03/05/2007 19:10:40 MSTNo reproduction or networking permitted without
24、license from IHS -,-,- Recent Developments in Concrete Pavement Systems 3 as the positive gradient. Consequently, the positive temperature gradient usually is the most interesting one. In the following two sections, positive temperature gradients are dealt with in beams and slabs, respectively. 2. R
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