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Consolidation is the process of removing entrapped air -from fresh concrete in the form. Several methods and techniques are available -- the choice depending mainly on the workability of the mix, placing conditions, and degree of deaeration desired. Some form of vibration is usually employed. This recommended practice includes up-to-date information on the mechanism of consolidation, and gives recommendations on equipment characteristics and pro-cedures for various classes of construction. [ABSTRACT FROM AUTHOR]

Large air and water pockets have been ob-served in the cores taken from well proportioned vibrated concrete pavements. Several parameters which may influence the volume of entrapped air in thin concrete sections compacted with spud vibra-tors are studied. Laboratory test results suggest that it is difficult to eliminate the entrapped air content in concrete slabs of stiff concrete com-pacted with spud type vibrators and for moderate vibration times ana vibrator amplitudes and fre-quencies. The results suggest that the use of a surcharge may be beneficial in reducing the en-trapped air content and a crushed stone concrete mix may yield lower entrapped air contents than a rounded stone concrete mix. [ABSTRACT FROM AUTHOR]

Most joints, and some cracks in concrete structures, require sealing against the adverse effects of environmental and service conditions. This report is a guide to better understanding of the properties of joint sealants and to where and how they are used in present practice. Described and illustrated are: the functioning of joint sealants; required properties, available materials and applicable specifications for field-molded sealants and pre-formed sealants such as waterstops, gaskets or compression seals; determination of joint movements, widths, and depths; outline details of joints and sealants used in general structures, fluid containers and pavements; methods and equipment for sealant installation including preparatory work; performance of sealants; and methods of repairing defective work or maintenance resealing. Finally, improvements needed to insure better joint sealing in the future are indicated. [ABSTRACT FROM AUTHOR]

Deformations at the corners of prestressed and reinforced concrete slabs were measured to study warping and its effect on the strength of pavement for Kuwait International Airport. The principal variables for the prestressed pavement were the length of slab, concrete strength, and compressive stresses through prestressing forces. For the reinforced concrete pavements the principal variables were the location of the corners at which the measurements were taken. The observations of the vertical movement due to warping at different times and different days were recorded and plotted in curves, for comparison between the vertical movement at the corners of the different slabs. A limited study for the extension of the warping along the two perpendicular edges meeting at the corner was done in one case. Also, a loading test at the corner of only one slab was done for investigating the value of the load required to bring the corner down to contact point and to find out if any failure could take place at the corner under the design load. [ABSTRACT FROM AUTHOR]

This report considers factors pertinent to the prestressing concept, reviews results of a number of experimental projects, and presents design details for experimental sections of prestressed pavement which can be built following existing highway construction practices in North America, and using commercially available prestressing equipment. Data are presented for slabs from 400 to 900 ft ( 120 to 270 m) long, 24 ft (7.3 m} wide, and 5 in. ( 13 em) thick, with post-tensioned tendons spaced 24 in. (61 em) on centers to provide at least 100 psi (7 kgf/cm²} effective prestress at midlength of the slab. Details are suggested for 600-ft (180-m) slabs. Post-tensioning is recommended to simplify operations using developed techniques, and to avoid the cost of pavement anchor blocks. The suggested design is supported by data from recent research on the performance of thin slabs under highway traffic. Length changes anticipated are predicted on the basis of trends in earlier experiments. The design for slab ends is intended to conservatively reinforce these critical locations, assure even joints, protect the foundation, and aid drainage rather than to meet minimum design needs with the most economical construction. [ABSTRACT FROM AUTHOR]

A direct method of solving for deflected shapes of freely discontinuous pavement slabs subjected to a variety of loads including transverse loads in plane forces and externally applied couples is presented. The method applies to slabs with freely variable foundation support including holes in the subgrade and rapidly solves finite element slab equations developed, unhindered by closure parameters necessary in iterative techniques of solution. A computer program uses equations and techniques developed. Sample problems illustrate generality of the method and convenience to the user. Results compare well with closed-form solutions and with previous solutions developed by other techniques. [ABSTRACT FROM AUTHOR]

Consolidation is the process of removing entrapped air from fresh concrete in the form. Several methods and techniques are available -- the choice depending mainly on the workability of the mix, placing conditions, and degree of deaeration desired. Some form of vibration is usually employed. This recommended practice includes up-to-date information on the mechanism of consolidation, and gives recommendations on equipment characteristics and procedures for various classes of construction. [ABSTRACT FROM AUTHOR]