This research project aims to use reactive powder concrete, RPC, as a new repair material and evaluate its bond strength and bond durability to existing concrete. One accelerated aging environment, namely a freeze-thaw cycle acceleration deterioration test, was selected for the evaluation of bond durability of the repair materials. Before and after aging, the samples were evaluated by the compressive strength, bond strength (slant shear test), steel pull out strength, and relative dynamic modulus NDT tests. The test results show that the RPC possesses high bond strength, dynamic modulus, and bond durability as compared with other concretes. The adhesion between the RPC and the steel is also much greater than that for the other concretes. It would be interesting to verify the consequences of this improved adhesion in reinforced concrete structures. Test results revealed that RPC was still in good condition after 1000 cycles of freezing and thawing in accordance with ASTM C 666-97. After 1000 cycles, the nonshrinkage high strength mortar showed a reduction in compressive strength, slant shear strength, steel pull out strength, and dynamic modulus by 17, 21, 24, and 25 %, compared with the corresponding values of 6, 7, 5, and 10 %, respectively, for RPC. Specimens of normal strength concrete were used as reference specimens. The 5 cm × 10 cm slant shear cylinders made of normal strength concrete had deteriorated severely after 600–700 freeze-thaw cycles. For the normal strength concrete, the average values of relative dynamic modulus of elasticity based on resonant frequencies after 300 and 600 freeze-thaw cycles were 75 and 55%, compared with the corresponding values of 96 and 92%, respectively, for RPC.
This study investigated the effects of applying three different types of rejuvenators on a highly aged parking lot pavement, which had shown some severe raveling. Cores were taken from the pavement before and after the treatments to examine the effects of these treatments. Tests were performed to determine the viscosity of the recovered asphalt binders from different layers of the pavement before and after the treatment. Right before coring, the surface texture and skid resistance were measured to assess whether the treatment had adversely affected the frictional properties of the pavement.
From both economical and ecological points of view, cold recycling is much more beneficial than hot recycling. However, due to not only the intrinsic properties of binding mechanisms but also the difficulties of process control, cold recycling did not gain common acceptance in Taiwanese paving industries. For the further development of environment-friendly paving materials and construction processes, this particular study investigated the engineering properties of foamed-asphalt-treated bases in Taiwan. Using a laboratory foaming plant, work was performed on local materials to produce foamed-asphalt-treated cold mixtures. The engineering properties of foamed-asphalt-treated mixes were tested and compared with those of hot recycled mixes. Test results show the benefits of utilizing high percentages (80%) of milled asphalt in foamed asphalt mixes. The optimum asphalt content of foamed asphalt mixes can be reduced from 3.5 to 2.0%, which is less than the mixes consisting of all new aggregate, and the moisture resistance of the mixture is enhanced. Resilience modulus and fatigue data show that foamed-asphalt-treated mixes perform as well as hot recycled mixes.
One of the top priorities for transportation authorities is to build a smooth pavement. A smoother pavement provides a better ride and reduces damage from dynamic traffic loading. Many different profilers have been selected by various transportation agencies to measure roughness. Roughness has been used in many specifications to determine if the contractor should obtain a bonus or penalty. Thus, a reliable device is needed to collect repeatable and defendable roughness values. The purpose of this study is to review, evaluate, and analyze six existing devices. Repetitive tests were conducted on both flexible and rigid pavements to determine the repeatability, correlation and limitations of these devices. Excellent correlations among devices have been developed with high R2. The 0.1 in. (2.54mm) blanking band yielded approximately 20% higher profile indexes than the 0.2 in. (5.08mm) band, and was more sensitive to roughness. The ARRB walking profiler yielded the highest precision, and is easy to operate and transport. Thus, the ARRB walking profiler was recommended for use on newly constructed pavement. The ARRB multiple laser profiler can be used for collecting profiles on existing pavements for management purposes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.