607MASS CONCRETE

606.03 CONSTRUCTION METHODS. Construction methods shall conform to the applicable

requirements of Sections 600 and 800 of these Specifications except as modified below.

606.03.1 Sampling of SCC Admixtures. A sample of SCC admixture may be taken by a

Department representative. Sampling and approv al of SCC admixtures shall conform to Subsection 601.02.2 of these Specifications.

606.03.2 Placement and Finishing of SCC. The placement of SCC shall be in accordance with

Sections 600 and 800 of these Specifications where applicable, except that a minimal amount of concrete vibrating is necessary to prevent segregation of SCC.

606.03.4 Testing of SCC. The testing of SCC shall be in accordance with Subsections 601.03.7,

809.03.09 and 816.03.6 where applicable except the following:

Slump Flow Test. This test will be in lieu of the conventional slump test. The slump flow range shall be 23 in. + 3 in. measured diameter as per ASTM C1611.

606.04 METHOD OF MEASUREMENT. The SCC admixture required for “Self-Consolidating

Concrete” will not be measured for payment.

606.05 BASIS OF PAYMENT. No separate payment will be made for the addition of the SCC

admixture required for “Self-Consolidating Concrete.” Portland cement concrete with SCC admixture will be paid for under the appropriate item or items as listed in the Proposal.

607.01 DESCRIPTION. This specification covers the requirements for concrete used in mass

concrete elements. Concrete proportioned for mass concrete applications shall conform to the applicable requirements of PARTS 600 and 800 of these specifications, together with the additional provisions set forth below. 607.01.1 DEFINITIONS. Mass Concrete is defined as any elements so specified on the Plans and any other concrete pour where the ratio of the total volume to the surface area of the element equals or exceeds 0.6 and has a minimum dimension of 3 feet in any of the three planes. Calculation of the ratio shall be performed based on all dimensions measured in feet. 6−43 Requirements for mass concrete construction include laboratory testi ng, thermal modeling, temperature monitoring, and providing concrete temperature control before, during, and after placement. All testing shall be performed at a laboratory with recognized AASHTO accreditations for performing the required tests (AASHTO T22, AASHTO T23, AASHTO T121, AASHTO T152, ASTM C1064, ASTM C1074), with the provision that no exception is taken by the Engineer with the Contractor’s choice of laboratory. The peak temperature is defined as the average of the values measured at any given time by the two temperature sensors placed at the lo cation of the highest tem perature as determined by the thermal model for the structural element. The highest acceptable peak temperature is 155°F. The differential temperature is defined as the difference in values measured at any given time between the temperature sensor(s) in any giv en location (or the average, if two sensors placed in the location) in the structural element and the peak temperature as defined above. The highest acceptable differential temperature until the completion of temperature control is 35°F. The performance-based differential temperature is defined as a limit that changes as the concrete gains strength, determined as a function of the established maturity curve for the mix. The benefit of this method is a potential acceleration of the production schedule over the use of a fixed limit. This option may be considered by the Engineer, with the proper submission of an implementation plan for the process as described herein, after the contractor has demonstrated compliance with the specifications of the concrete mix during batching, placement and curing.

607.02 Materials and Equipment.

607.02.1 CONCRETE. The concrete shall meet the app licable material requirements of SECTION

808 and SECTION 601 . Unless specified in the contract documents, calcium nitrite based corrosion inhibitor shall not be used in Mass Concrete mixtures. Any proposed mixture adjustment that meets the requirement in SECTION 601 for a new approval of the mix design will also require a new approval of the mass concrete temperature control plans per this specification. 607.02.2 TEMPERATURE AND MATURITY RECORDING. Primary temperature measuring loggers shall be designed specifically for determining the maturity of concrete in accordance with ASTM C1074. They shall operate in the range of 0°F to 212°F to an accuracy of +/- 1°F and internally record the time and temperature at a minimum of 1 hour intervals for a minimum of 90 days. Each logger shall have a unique serial number and shall upon download of the information using the compatible reader or other appropriate data connection, produce a secure (unalterable) Windows PC-readable file that identifies the logger by its serial number and the start date. Software shall be provided to develop maturity curves to predict strength and display the temperature versus time data for all of the loggers in a given placement. The data leads shall be sized to reach from the logger's installed location to an accessible site where a handheld reader can be employed. A data cable that can connect the loggers to a notebook computer or other standard mobile device will be considered equivalent to a handheld reader, providing a Windows PC-readable file can be created that can be transferred to a Windows PC. The Contractor shall provide a reader and nec essary software for the exclusive use of the Engineer. The reader and software provided for t he Engineer shall become the property of the State at the completion of the project. The loggers selected by the Contractor shall have the capability to use battery operated