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原文传递 Effect of Early-Age Concrete Elastic Properties on Fatigue Damage in PCC Pavements Containing Fibers.

题名：	Effect of Early-Age Concrete Elastic Properties on Fatigue Damage in PCC Pavements Containing Fibers.
作者：	Issa, M. A.
关键词：	Concrete pavement, Flexural strength tests, Synthetic fibers, Cyclic fatigue, Dynamic modulus, Toughness, Fracture-mechanics, Maturity, Freeze–thaw, Dowel bars, Jointed pavement, Nondestructive, Portland cement concrete (PCC) pavement, Mechanical properties testing, Soil conditioning, Fatigue damage detection, Illinois Department of Transportation (IDOT) Corridor, University of Illinois Chicago
摘要：	The Illinois Department of Transportation (IDOT) is revising current specifications for opening new PCC (Portland cement concrete) pavements to traffic. These revisions will help keep closure times at a minimum by specifying the required concrete strength for resisting early-age fatigue damage. An extensive experimental program was conducted at the University of Illinois at Chicago to determine the elastic properties of IDOT pavement (PV) and patch (PP1, PP2) mixes at early concrete age. The experimental program included testing concrete specimens as early as 12 hr with two curing regimes (73°F and 50°F). The effect of fiber inclusion was investigated by considering two types of IDOT-certified synthetic macro-fibers (W.R. Grace Strux 90/40 and BASF Master Fiber MAC Matrix) with quantities of 0, 4, 6, and 8 lbs. /yd3. The experimental program initiated with determining mechanical properties of early-age pavement and patch concrete mixes for compressible strength, flexural strength, flexural toughness, static modulus of elasticity, and linear drying shrinkage. The fracture behavior, flexural fatigue performance, and durability against freezing and thawing were investigated at early concrete age. The study also evaluated the effectiveness of nondestructive measures such as maturity and dynamic modulus of elasticity tests for predicting the strength gain for IDOT pavements mixes. Experimental and numerical data was implemented into a practical solution for opening PCC pavements to traffic loads at an early age. The proposed step-by-step procedure evaluates the fatigue life of rigid pavements for a predefined thickness, soil condition, and concrete age. Designs aids were accordingly developed for accurately estimating concrete flexural strength, pavement tensile stress, and corresponding fatigue life through practical equations, charts, and nomographs. With fiber inclusion yielding an improved structural performance, the experimental testing program was further extended by evaluating the fatigue behavior of jointed, plain-concrete pavement (JPCP) specimens at early concrete age. For this experimental task, the loading sequence, fiber content, pavement thickness, and dowel presence were investigated for a critical loading case at contraction joints. Experimental results were satisfactory for plain and fiber-reinforced jointed-slab specimens subjected to early-age cyclic fatigue loading.
报告类型：	科技报告