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原文传递 THE EFFECTS OF HIGHER STRENGTH AND ASSOCIATED CONCRETE PROPERTIES ON PAVEMENT PERFORMANCE.

题名：	THE EFFECTS OF HIGHER STRENGTH AND ASSOCIATED CONCRETE PROPERTIES ON PAVEMENT PERFORMANCE.
作者：	Hansen-W; Jensen-EA; Mohr-P
关键词：	Aggregates-; Aging-Materials; Air-voids; Climate-; Climatic-regions; Compressive-strength; Concrete-pavements; Faulting-; Field-tests; Flexural-strength; Jointed-plain-concrete-pavements; Laboratory-tests; Mix-design; Pavement-distress; Pavement-joints; Pavement-performance; Permeability-; Portland-cement-concrete; Shrinkage-; Spacing-; Spalling-; Tensile-strength; Thermal-expansion; Traffic-; Transverse-cracking; Water-cement-ratio
摘要：	The major goal of this project was to develop recommendations for portland cement concrete (PCC) properties and materials characteristics found in higher strength jointed plain concrete pavements (JPCPs) with improved long-term performance as determined by joint spalling and faulting, and transverse slab cracking. Primary project variables were pavement age, climate, traffic [4 to 23 million equivalent single axle loads (ESALs)], distress levels and types, joint spacing, and compressive strength. Fifteen JPCPs were selected for detailed field and laboratory investigation. The field compressive and tensile strengths (splitting) ranged from 33 to 75 MPa and from 3.1 to 4.5 MPa, respectively. Regular strength highway concrete with a design flexure strength of about 4.5 MPa can develop excellent long-term joint spalling resistance provided that (1) good sub-surface drainage conditions are present, (2) the concrete reaches low permeability level over time from additional curing (i.e., high resistance to physical and chemical deterioration from rapid chloride and water permeability test), (3) it has good entrained air void system (i.e., 6 to 8.5%), and (4) sound aggregate are used in the concrete mix. Several different permeability tests were evaluated, and each showed a good correlation with compressive strength. The compressive strength test is therefore a good indicator of the permeability level. The range of low permeability can typically be achieved at a compressive strength range of 45 to 50 MPa. Water-cementitious ratio was found to be the major mix feature controlling compressive strength. This requires a concrete mix with a water-cementitious ratio of 0.42 to 0.45, a cement content of about 335 kg per cu m, and well-graded quality aggregate. Several aggregate characteristics of the concrete mix were found important to achieve good long-term pavement performance. These included aggregate inertness with respect to alkali aggregate reaction and freeze-thaw test, and strong and large sized coarse aggregate to ensure good cracking resistance and aggregate interlock. In addition, well-graded aggregates were beneficial in reducing the paste volume fraction. This results in low coefficient of thermal expansion and drying shrinkage, which are both important properties for avoiding premature transverse cracking. Given sufficient slab thickness, good long-term resistance to fatigue (transverse) cracking was found at any flexure strength level of 4.5 to 6 MPa, provided that loss of slab support from pumping erosion was not a factor. Joint faulting was found to be a consequence of factors causing pumping erosion and/or slab settlement and it was not affected by PCC strength level. Prototype mix d?600
总页数：	2001/06. pp256 (Phots., Figs., Tabs., Refs.)
报告类型：	科技报告