1,058 research outputs found

    Performance Evaluation of Open Graded Base Course with Doweled and Non-Doweled Transverse Joints

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    The objectives of this study were to investigate the performance of 20-year old doweled/non-doweled and dense-graded/permeable base test sections on three concrete pavement segments in Wisconsin: USH 18/151 in Iowa and Dane counties, STH 29 in Brown County, and USH 151 in Columbia and Dane Counties. Five pavement bases were placed including: dense graded, asphalt-stabilized permeable, cement-stabilized permeable, and untreated permeable having two gradation sizes. USH 18/151 test sections had similar performance (PDI) for doweled unsealed pavement on dense and permeable base. Distresses common to all segments included slight to moderate distressed joints/cracks and slight transverse faulting. Asphalt-stabilized permeable base had no slab breakup or surface distresses, however it measured a greater severity of distressed joints and cracks. Non-doweled sections having asphalt-stabilized permeable base and Transverse Inter Channel drains had better performance and ride than the other non-doweled sections. IRI was generally higher on non-doweled pavements, but many doweled sections had an equal roughness to non-doweled sections. Sealed non-doweled joints produced a better performing pavement, however, sealant did not appear to improve ride. STH 29 unsealed sections performed better than the median PDI for the sealed sections. The sealed doweled pavement did perform a little better than the non-doweled section, but the opposite occurred on the non-doweled sections. Sealed doweled joints had a smoother ride than the other combinations. USH 151 test sections found the finer-graded New Jersey permeable base had the smoothest ride when compared to other permeable sections. Asphalt-stabilized permeable base had the roughest ride, and unstabilized and cement-stabilized permeable bases had intermediate values. The average hydraulic conductivity for the unstabilized permeable base was 17,481 feet per day and there appears little variation due to doweling or joint sealant. Deflection load transfer results indicate expected high average values for the doweled sections and fair to poor values for the non-doweled sections. Slab support ratios indicate variable results based on base type and joint reinforcement/sealant. Life-cycle cost analysis found dense-graded base was the least cost among all base alternatives, with a total estimated present-worth life-cycle cost of $665,133 per roadway mile. Untreated and asphalt-stabilized permeable bases were more expensive by 13% and 27%, respectively. Other factors in selecting dense-graded base over permeable base include project drainage conditions set forth in the FDM guidelines an anticipated increase in pavement surface roughness

    Investigation of Feasible Pavement Design Alternatives for WisDOT

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    The current pavement design and selection process of WisDOT for all new pavements or reconstructions of existing pavement structures provides for the design of one asphaltic concrete (AC) and one portland cement concrete (PCC) pavement alternative. Life-cycle costs analyses are then used to determine the preferred alternative for construction. Previous restrictions in the WisDOT pavement selection process have essentially excluded the construction of thick AC (AC thickness \u3e 150 mm) and thin PCC (PCC thickness \u3c 225 mm) pavements and thus the validity of current life-cycle cost inputs for these pavement types is under question. This report presents a performance analysis of existing thick AC and thin PCC pavements constructed in and around Wisconsin. The performance trends developed indicate current design assumptions utilized by WisDOT, related to the expected service life to first rehabilitation of AC and PCC pavements, may also be used for thick AC and thin PCC pavements

    Restoration of Fricitonal Characteristics on Older Portland Cement Concrete Pavement:Final Report for Iowa Highway Research Board Project HR-224, June 1986

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    Safety i s a very important aspect o f the highway program. The Iowa DOT initiated an inventory o f the friction values of all paved primary roadways i n 1969. This inventory, with an ASTM E-274 test unit, has continued to the present time. The t e s t i n g frequency varies based upon traffic volume and the previous friction value. Historically , the state o f Iowa constructed a substantial amount o f pcc pavement during the 1928-30 period t o "get Iowa out o f the mud". Some of that pavement has never been resurfaced and has been subjected to more than 50 years o f wear. The textured surface has been worn away and has subsequently polished. Even though some pavements from 15 t o 50 years old continue t o function structurally , because of the loss of friction , they do not provide the desired level o f safety to the driver. As a temporary measure, "Sl ippery -When -Wet " signs have been posted on many older pcc roads due to friction numbers below t h e desirable level. These signs warn the motorist of the current conditions. An economical method of restoring the high quality frictional properties i s needed

    Investigation of PCC Pavement Deterioration: A Few Facts are Worth More than 100 Opinions, Interim Report, HR-2074, 1995

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    Portland Cement Concrete (PCC) pavement has served the State of Iowa well for many years. The oldest Iowa pavement was placed in LeMars in 1904. Beginning in 1931, many miles of PCC pavement were built to "get out of the mud.” Many of these early pavements provided good performance without deterioration for more than 50 years. In the late 1950's, Iowa was faced with severe PCC pavement deterioration referred to as D cracking. Research identified the cause of this deterioration as crushed limestone containing a bad pore system. Selective quarrying and ledge control has alleviated this problem. In 1990, cracking deterioration was identified on a three year old pavement on us 20 in central Iowa. The coarse aggregate was a crushed limestone with an excellent history of performance in PCC pavement. Examination of cores showed very few cracks through the coarse aggregate particles. The cracks were predominately confined to the matrix. The deterioration was identified as alkali-silica reactivity (ASR) by a consultant

    Evaluation of Rumble Stripes on Low-Volume Rural Roads in Iowa—Phase II Final Report, November 2011

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    Single-vehicle run-off-road crashes are the most common crash type on rural two-lane Iowa roads. Rumble strips have proven effective in mitigating these crashes, but the strips are commonly installed in paved shoulders on higher-volume roads that are owned by the State of Iowa. Lower-volume paved rural roads owned by local agencies do not commonly feature paved shoulders but frequently experience run-off-road crashes. This project involved installing rumble stripes, which are a combination of conventional rumble strips with a painted edge line placed on the surface of the milled area, along the edge of the travel lanes, but at a narrow width to avoid possible intrusion into the normal vehicle travel paths. The research described in this report was part of a project funded by the Federal Highway Administration, Iowa Highway Research Board, and Iowa Department of Transportation to evaluate the effectiveness of edge-line rumble strips in Iowa. The project evaluated the effectiveness of rumble stripes in reducing run-off-road crashes and in improving the longevity and wet-weather visibility of edge-line markings. This project consisted of two phases. The first phase was to select pilot study locations, select a set of test sites, install rumble stripes, summarize lessons learned during installation, and provide a preliminary assessment of the rumble stripes’ performance. The purpose of this report was to document results from Phase II. A before and after crash analysis was conducted to assess whether use of the treatment had resulted in fewer crashes. However, due to low sample size, results of the analysis were inconclusive. Lateral position was also evaluated before and after installation of the treatment to determine whether vehicles engaged in better lane keeping. Pavement marking wear was also assessed

    Highly Abrasion-resistant and Long-lasting Concrete

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    Studded tire usage in Alaska contributes to rutting damage on pavements resulting in high maintenance costs and safety issues. In this study binary, ternary, and quaternary highly-abrasion resistant concrete mix designs, using supplementary cementitious materials (SCMs), were developed. The fresh, mechanical and durability properties of these mix designs were then tested to determine an optimum highly-abrasion resistant concrete mix that could be placed in cold climates to reduce rutting damage. SCMs used included silica fume, ground granulated blast furnace slag, and type F fly ash. Tests conducted measured workability, air content, drying shrinkage, compressive strength, flexural strength, and chloride ion permeability. Resistance to freeze-thaw cycles, scaling due to deicers, and abrasion resistance were also measured. A survey and literature review on concrete pavement practices in Alaska and other cold climates was also conducted. A preliminary construction cost analysis comparing the concrete mix designs developed was also completed

    The Relationship of Ferroan Dolomite Aggregate to Rapid Concrete Deterioration, HR-266, 1987

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    Some of Iowa's 13,200 miles of portland cement concrete (pcc) pavement have remained structurally sound for over 50 years while others have suffered premature deterioration. Research has shown that the type of coarse aggregate used in the pcc is the major cause of this premature deterioration. Some coarse aggregates for concrete exhibit a nonuniform performance history. They contribute to premature deterioration on heavily salted primary roadways while providing long maintenance-free life on unsalted secondary pavements. This inconsistency supports the premise that there are at least two mechanisms that contribute to the deterioration. Previous research has shown that one of these mechanisms is a bad pore system. The other is apparently a chemical reaction. The objective of this research is to develop simple rapid test methods to predict the durability of carbonate aggregate in pcc pavement. X-ray diffraction analyses of aggregate samples have been conducted on various beds from numerous quarries producing diffraction plots for more than 200 samples of dolomitic or dolomite aggregates. The crystalline structures of these dolomitic aggregates show maximum-intensity dolomite/ankerite peaks ranging from a d-spacing of 2.884 angstroms for good aggregates to a d-spacing of 2.914 angstroms for nondurable aggregates. If coarse aggregates with known bad pore systems are removed from this summary, the d-spacing values of the remaining aggregates correlate very well with expected service life. This may indicate that the iron substitution for magnesium in the dolomite crystal is associated with the instability of the ferroan dolomite aggregates in pcc pavement

    Microstructural, Mechanical and Physical Assessment of Portland Cement Concrete Pavement Modified by Sodium Acetate under Various Curing Conditions

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    Portland Cement Concrete (PCC) pavement was studied with incorporation of an environmentally friendly eco-additive, sodium acetate (C2H3NaO2). This additive was added to PCC pavement in three different percentages of 2%, 4% and 6% of binder weight. For a comprehensive elucidation of the eco-additive incorporation on the performance of PCC pavement, casted samples were cured in three different environments, namely: water, outdoors and pond water. Water absorption tests, flexural and compressive strength tests after 7 and 28 days of curing were conducted and results compared with the control samples without any addition of sodium acetate. Results demonstrated a significant improvement in the impermeability, compressive strength and flexural strength of PCC pavement when sodium acetate concrete is cured in a water bath and outdoors. However, no/little improvement in the impermeability, compressive strength and flexural strength was observed in sodium acetate samples that were cured in pond water. Microstructural analysis of treated samples by using scanning electron microscopy (SEM) illustrated the strengthening effect that sodium acetate provides to the pore structure of concrete pavement

    Assessment of the Functional Performance of Mohammed Al-Qasim Expressway Pavement Surface

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    تهدف أنظمة النقل إلى توفير حركة آمنة وكفوءة للناس والبضائع. ولتحقيق هذه المتطلبات تحتاج الى تقييم حالة سطح التبليط (كفاءه الاداء الوظيفي لسطح التبليط). يتأثر التبليط بالعديد من العوامل ويتعرض للتدهور مع مرور الزمن. حيث تؤثر هذه الاضرار التي تحدث بشكل متكرر على راحة وامان مستخدمي الطريق. تقييم حالة سطح التبليط هو الخطوة االاساسية لاختيار برنامج الصيانة المناسب. تهدف هذه الدراسة الى تقييم الاداء الوظيفي لسطح تبليط طريق محمد القاسم السريع باستخدام طريقة مؤشر حالة التبليط ((PCI لمقطعين من الطريق، بعد اجراء عملية المسح وتحديد نوع وكمية وشدة كل نوع من انواع الضرر الموجود في التبليط خلال سنة 2017 أظهرت نتائج تصنيف سطح التبليط الكونكريتي (الجزء الاول) على أنه في حالة مرضية او مقبولة، وان مؤشر حالة التبليط: 70 في حين تم تصنيف السطح الاسفلتي (الجزء الثاني) على انه في حالة متوسطة استنادا إلى قيم مؤشر حالة التبليط (PCI): 77.To achieve these requirements need to assess the pavement surface condition (Functional Performance). The pavement surface damage that frequently happens has an effect on the safety and comfort of road users. Pavement condition assessment is the basic step to select a suitable type of maintenance and rehabilitation program. This study aims to estimate the functional condition of the Mohammed Al-Qasim Expressway pavement surface by the Pavement Condition Index (PCI) assessment with data collected throughout 2017. The result showed that the AC pavement surface condition assessment is equal to 70 based on PCI value, and rated as fair, and the transverse tining PCC pavement surface condition is rated as satisfactory and PCI value equals 77

    Verification of the whitetopping thickness design procedure for asphalt concrete overlaid Portland cement concrete pavements

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    Iowa is one of few states with a large number of Portland Cement Concrete (PCC) pavements. Many of these pavements have been rehabilitated by placing multiple layers of Asphalt Concrete (AC) over the existing PCC slabs. However, there was a need for an alternative with a longer life and lower life-cycle cost. With improvements in paving technology such as the slipform paver and the ability to obtain high early age strength, PCC overlays soon became that alternative. Many of the existing overlay design procedures were developed for a single placed layer of pavement and are not applicable to the two layered AC/PCC pavements. Previous research developed a method so that the single placed layer concept can be applied to the analysis and design of overlays for AC/PCC pavements. The study presented here is an extension of this research. It investigates existing design methodologies and presents modifications for future research
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