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At some construction sites in Mississippi, deterioration of concrete in contact with the surrounding soil could be related to the high sulfate content of the adjacent soils. Studies dating to 1966 have documented sulfate attack associated with specific types of sulfide or sulfate-rich soils. Future highway-related construction must include specified procedures and materials that will ensure the service life of concrete construction is not reduced by such aggressive soils. In this project, three portland cements and five pozzolans, which can be used as cement replacements, were investigated to determine which of these cements and/or cement blends could be categorized as sulfate-resistant. Two screening procedures, the University of California Pavement Research Center's Caltrans rapid sulfate test and the American Society for Testing and Materials' Standard C1012 (standard test method for length change), were used to evaluate the cements/blended cements. Results from the Caltrans test identified only one of the blended cements investigated that failed to qualify as sulfate resistant. The results from the bar expansion test (ASTM C1012) indicated that only one cement evaluated would not meet the criterion for an American Concrete Institute (ACI) Class 1 sulfate-resistant cement., The original document contains color images.

Engineers at the Vicksburg District (MVK) of the U.S. Army Engineer Division, Mississippi Valley (MVD), are responsible for the design and construction of levees all along the Mississippi River and its tributaries within the District's boundaries. The local Levee Boards are responsible for maintaining approximately 990 miles (1.6 million meters) of unpaved roads, and the District is responsible for maintaining approximately 390 miles (627,000 m) of unpaved roads that reside on top of the levees. Over the years, the MVK has developed its own specifications to meet these needs. Historically, MVK has relied upon sources of sand clay-gravel that could provide consistent products. However, these sources are becoming depleted, so the products have recently become inconsistent. As a result, the MVK has expanded its specifications to facilitate bid submittal by producers of crushed aggregates. The purpose of the investigation reported herein was to improve the MVK, MVD, specifications by characterizing various aggregate types in the laboratory, along with collecting performance data under traffic. Because of MVK's recent struggles in finding consistent aggregate sources, both natural and crushed sources of aggregate were included in this study. Trafficking and performance monitoring were accomplished under controlled test track conditions. A review of specifications used by other agencies was also conducted in order to take advantage of their knowledge., The original document contains color images.

Materials for expedient roadway pavement repairs must provide a trafficable repair in a minimal amount of time. Therefore, any repair material must be able to cure quickly and be easy to use. There are a large number of proprietary cementitious rapid repair materials for both asphalt and concrete pavements. Three types of cementitious materials were used to make acceptable expedient repairs to an asphalt roadway. Trafficking showed that these materials were not flexible enough to provide durable repairs to flexible pavements in hot weather. There are a number of proprietary asphalt based repair materials. These materials can generally be trafficked immediately after placement with some displacement, depending upon the loads. These products will gain more stability with time and with cooler temperatures. Repair materials using cut-back asphalts generally provide the best combination of workability and long-term storage under adverse conditions, particularly freezing temperatures. This study evaluated the asphalt repair materials for workability, strength using Marshall stability and triaxial testing, and durability in regards to cohesion and adhesion properties. The majority of repair materials use an open-graded mixture and the Marshall stability test is not appropriate for this type of gradation. The proprietary cold mixtures were all easier to apply and work with than the conventional cold mix. The products that advertised placement into wet holes all preformed well and provided equal performance in both wet and dry holes for the traffic and evaluation period used., Project no. AT40.

The investigation described in this report evaluated the accuracy of four moisture meters to consistently measure fine-aggregate moisture contents and to evaluate the operational features of the instruments. No data were developed in this investigation that would indicate that any of the four commercial devices studied was superior to others or would be incapable of supplying adequate information upon which to base control of surface moisture levels of fine aggregate. The devices appear to have a level of precision of the same order as the hot plate method (CRD-C 113); there was no consistent pattern of bias.

This report presents the results of a research program examining the effects of different methods of preparing horizontal construction joints in mass concrete construction. The purpose of the research program was to confirm existing guidance or, if necessary, update it. This is the second and final report. The joint moisture conditions at the time of concrete placement were: (a) continuously moist, (b) dry, and (c) dry and then remoistened. There was no cleaning of the joint surface prior to placement of a second lift. The concrete mixture used in the first lift was proportioned to minimize bleeding and the resulting laitance. Jointed specimens were tested for direct tensile strength and shear strength. The results indicated that an addition of a small quantity of silica fume does decrease bleeding and reduce loose, flaky laitance. However, a smooth, somewhat glassy surface appears to interfere with the bonding of the next lift of concrete. Bond strengths are not as good as those when the horizontal construction joints are cleaned by high-pressure water cutting or by air-water cutting, and then allowed to dry approximately 24 hr immediately prior to placement of the next lift of concrete. This technique is not recommended. Current guidance concerning joint cleaning procedures should be followed.

This report presents the results of a laboratory investigation that was conducted for the purpose of validating mixer- uniformity requirements for roller-compacted concrete. The purpose of the investigation was to verify existing guidance or, if necessary, recommend changes to existing guidance. The investigation included both air-entrained and nonair-entrained concrete. The results indicate that existing guidance is appropriate for Vebe consistency, water content, coarse aggregate content, compressive strength, and air-content determinations. However, the results indicated that existing guidance could he too restrictive for the unit weight of air-free mortar determinations. A recommendation was made to consider revising current guidance on the allowable range for unit weight of air-free mortar.

Technical Report REMR-CS-55 February 1998 US Army Corps of Engineers Waterways Experiment Station Repair, Evaluation, Maintenance, and Rehabilitation Research Program Evaluation of Criteria for Uniformity of Roller-Compacted Concrete by Brian H. Green, Billy D. Neeley, Toy S. Poole Approved for Public Release; Distribution is Unlimited TA 7 .W34t REMR-CS55 1998 Prepared for Headquarters, U.S. Army Corps of Engineers Library Larsau of ßeclafihaücn Dsnvor, Colorado The following two letters used as part of the number designating technical reports of research published der the Repair, Evaluation, Maintenance, and Rehabilitation (REMR) Research Program identify the problem area under which the report was prepared: Problem Area Problem Area cs Concrete and Steel Structures EM Electrical and Mechanical GT Geotechnical El Environmental Impacts HY Hydraulics OM Operations Management CO Coastal S & BUREAU OF RECLAMATION DENVER LIBRARY 92065291 Repair, Evaluation, Maintenance, and Rehabilitation Research Program Technical Report REMR-CS-55 February 1998 Evaluation of Criteria for Uniformity of Roller-Compacted Concrete by Brian H. Green, Billy D. Neeley, Toy S. Poole U.S. Army Corps of Engineers Waterways Experiment Station 3909 Halls Ferry Road Vicksburg, MS 39180-6199 Final report Approved for public release; distribution is unlimited P repa red fo r U.S. Army Corps of Engineers Washington, DC 20314-1000 U nder Work Unit 32639 92065291 US Army Corps of Engineers Waterways Experiment Station HEADQUARTERS BUUXNa ENTRANCE FOR INFORMATION CONTACT: PUBLIC AFFAIRS OFFICE U.S. ARMY ENGINEER WATERWAYS EXPERIMENT STATION 3909 HALLS FERRY ROAD VICKSBURG, MISSISSIPPI 39180-6199 PHONE: (601)634-2502 area CF RESERVAT©* , Waterways Experiment Station Cataloging-in-Publication Data Green, Brian H. Evaluation of criteria for uniformity of roller-compacted concrete / by Brian H. Green, Billy D. Neeley, Toy S. Poole ; prepared for U.S. Army Corps of Engineers. 35 p. : ill. ; 28 cm. — (Techni

Maturity parameters were determined on a mass concrete mixture according to American Society for Testing and Materials (ASTM) C 1074. Time-temperature measurements were made on two concrete placements at Red River Lock and Dam 4 for the first 40 to 60 days after placement. These data were used to predict strengths from the concrete's maturity. The placements were also cored to determine in-place strength. Strength development within the first few days of placing were reasonably well predicted by maturity, but predicted and measured strength differed widely after that. Large uncertainties in the maturity parameters were encountered. Probable causes of the large differences and the large uncertainties are discussed and recommendations made on modifications to the procedure for mass concrete.

This report presents the results of a research program examining the effects of different methods of preparing horizontal construction joints in mass concrete construction. The purpose of the research program was to confirm existing guidance or, if necessary, update it. The joint cleaning procedures employed were (a) none, (b) high-pressure water cutting, (c) air-water cutting, and (d) air-water cutting to greater depth. The joint moisture conditions at the time of concrete placement were (a) continuously moist, (b) dry, and (c) dry and then remoistened. Jointed specimens were tested for direct tensil strength, shear strength, and permeability. The results indicated that good bond strengths are realized when horizontal construction joints are cleaned by high-pressure water cutting or by air-water cutting, and that undercutting coarse aggregate particles does not improve the strength of the joint. The results also indicated that better bond strengths are realized when the joint surface is allowed to dry approximately 24 hr immediately prior to placement of the next lift of concrete. Recommendations are made to consider revising current guidance to permit placement of concrete on a dry surface. No revisions to current guidance are recommended concerning joint cleaning procedures.

Technical Report SL-96-2 February 1996 US Army Corps of Engineers Waterways Experiment Station Methods of Preparing Horizontal Construction Joints in Mass Concrete by Billy D. Neeley, Toy S. Poole Approved For Public Release; Distribution Is Unlimited Prepared for Headquarters, U.S. Army Corps of Engineers The contents o f this report are not to be used for advertising, publication, or promotional purposes. Citation of tradenames does not constitute an official endorsement or approval of the use of such commercial products. PRINTED ON RECYCLED PAPER Technical Report SL-96-2 February 1996 Methods of Preparing Horizontal Construction Joints in Mass Concrete by Billy D. Neeley, Toy S. Poole U.S. Army Corps of Engineers Waterways Experiment Station 3909 Halls Ferry Road Vicksburg, MS 39180-6199 Final report Approved for public release; distribution is unlimited Prepared for U.S. Army Corps of Engineers Washington, DC 20314-1000 Waterways Experiment Station Cataloging-in-Publication Data Neeley, Billy D. Methods of preparing horizontal construction joints in mass concrete / by Billy D. Neeley, Toy S. Poole ; prepared for U.S. Army Corps of Engineers. 80 p. : ill. ; 28 cm. ~ (Technical report; SL-96-2) Includes bibliographic references. 1. Joints (Engineering) 2. Concrete construction — Joints. I. Poole, Toy S. (Toy Spotswood), 1946- II. United States. Army. Corps of Engineers. III. U.S. Army Engineer Waterways Experiment Station. IV. Structures Laboratory (U.S. Army Engineer Waterways Experiment Station) V. Title. VI. Series: Technical report (U.S. Army Engineer Waterways Experiment Station); SL-96-2. TA7 W34 no.SL-96-2 Contents Preface ............................................................................................................ iv 1— Introduction .............................................. 1 Background ....................................................................................................... 1 Objectives ...................................

This report reviews some of the literature pertaining to the use of large amounts of fly ash in concrete. Summaries of experience with high fly ash concrete are presented, both as reported from laboratory studies and from published summaries of experience in construction. Areas in which increased research is necessary are identified. (MM)