290 SECTION 514 ROLLER COMPACTED CONCRETE
514.1 -DESCRIPTION : Roller Compacted Concrete (RCC) consists of aggregate, Portland cement and possibly other supplementary cementitious mater ials (fly ash, slag), and water. RCC is proportioned, mixed, placed, compacted, and cured in accordance with these specifications. Ensure that the RCC conforms to the lines, grades, thickness, and typical cross section shown in the plans or otherwise est ablished by the WVDOH. When used as base course, it shall be constructed as shown in the plans.
514.2 -MATERIALS : Materials shall conform to the requirements of the following Subsection of Division 700:
MATERIAL SUBSECTION Coarse Aggregate 703.1 -4 Curing Materials 707.6 -707.10 Fine Aggregate Note 1 702.1 Portland Cement 701.1, 701.3 Pozzolanic Additives 707.4 Water 715.7 Water Reducing and Retarding Admixtures 707.2 Note 1 The use of limestone as fine aggregate will not be permitted
Shipping and storage of Cement and Pozzolanic Additives: Cement and pozzolanic additives shall be shipped and stored as outlined in Section 501.2.
514.2.1 -Material Requirements: Aggregates: Use no aggregate where the plasticity index of the aggregate exceeds 5. Aggregates may be a blend of fine and coarse aggregates. Use well -graded aggregate without gradation gaps and conforming to the following gradation:
Sieve Size % Passin g by Weight 1 inch 100 3/4 inch 95-100 1/2 inch 70-90 3/8 inch 60-85 #4 40-60 #16 20-40 #100 3-15 #200 0-8
Prior to the start of each day’s production, the Contractor shall perform a gradation test on the material to be used that day in order to verify that the aggregate gradation meets the above requirements. If the results of this test show that the aggregat e gradation does not meet the above requirements, the Contractor shall immediately notify the Engineer and shall not begin
291 production that day unless approved to do so by the Engineer. The Contractor shall then take immediate action to correct any gradati on not meeting the above requirements, regardless of whether or not production is allowed. All gradation test results shall be submitted to the Engineer within seventy -two (72) hours.
514.3 -PROPORTIONING : 514.3.1 -RCC Mix Design R equirements: At least 45 days prior to the start of construction, the Contractor shall submit to the Engineer for approval the proportion of materials to be used which will result in a workable RCC mix. No more than 25%, by mass, of the cementitious material content o f the RCC mix shall be pozzolanic materials. The Engineer will review these proportions within 14 (fourteen) Calendar Days. Laboratory density tests, in accordance with AASHTO T 180 (Method D), shall be performed during development of the mix design i n order to determine the maximum laboratory density and optimum moisture content for the RCC mix. The material proportions used to achieve the maximum laboratory density and the optimum moisture content shall be the material proportions used in the approved mix design and during construction. Compressive strength tests, as outlined in Section 514.3.2 shall be conducted on at least two separate batches of RCC developed from these material proportions. The mix design results shall be reported on the attachments for MP 711.03.23. The maximum laboratory density and optimum moisture content shall be reported and included on the mix design submittal also. The mix design shall be accompanied by a document listing the source of materials and certified test data from a Division approved laboratory demonstrating the adequacy of the mix design. The Contractor shall notify the Engineer of any change in the sourc e of materials or the addition of admixtures during the progress of work, since such change may necessitate a new mix design.
514.3.2 -Design Compressive Strength: A mix design shall be used which demonstrates a minimum compressive strength of 4500 psi within 28 days. Compressive strength specimens shall be prepared in accordance with ASTM C1435 and tested in accordance with AASHTO T 22. At least three sets of three cylinders shall be produced, with one set being tested at 3 days, one set being tested at 7 days, and the other at 28 days. The compressive strength at a particular age shall be determined as the average of the three specimens. If one individual result is much lower or much higher than the other two due to defects in the specimen as outli ned in section 601.4.4, that value shall be discarded.
514.3.3 -Design Moisture Content: A test for moisture content, in accordance with ASTM C566, shall be performed on each of the RCC batches produced in Section 514.3.1, from which compressive strengt h specimens were fabricated. The average moisture content shall be considered the target evaporable moisture content of the RCC mix, and shall be used for quality control purposes as outlined in Section 514.4.2.1.
514.3.4 -Test Section: If the mix de sign appears satisfactory to the Engineer, the Contractor shall prepare and test a trial batch mixture and representative test section at least 100 f eet in length and ten (10) feet in width to verify that the design criteria for strength and density are me t. The criteria for strength and lift thickness shall be verified by the Contractor by taking three cores at random locations and testing them in accordance with AASHTO T24. The minimum required compressive strength for each of these cores is 3,500 psi, measured at an age no later than 28 days, or within 10 percent (10%) of either the 3 or 7 -day mix design strength, as determined in
292 Section 514.3.2. Density testing, as outlined in Section 514.4.2.3 shall be performed on this Test Section also. The minimum required density for this testing is 98 percent (98%) of the maximum laboratory density. Perform batch mixture preparation and testing in the presence of representatives of the Engineer. Construction, using RCC, shall not begin until an approved mix design has been obtained. The Test Section shall be located in a location approved by the Engineer. If permitted by the Engineer, it is acceptable to place and leave the Test Section in place as part of the completed pavement if it meets all of t he above required testing and acceptance criteria. If the Test Section is placed in an area which is to be paved with RCC, and it does not meet all of the above acceptance criteria, it shall be removed at the Contractor’s expense.
514.4 -TESTING : 514.4.1 -Test Methods:
Standard Practice for Molding Roller -Compacted Concrete in Cylinder Molds Using a Vibrating Hammer ASTM C1435 Compressive Strength of Cylindrical Concrete Specimens AASHTO T 22 Making and Curing of Concrete Specimens AASHTO T 23 Obtaining and Testing Drilled Core Specimens AASHTO T 24 Measuring Length of Drilled Concrete Cores AASHTO T 148 Standard Test Method for Total Evaporable Moisture Content of Aggregate by Drying ASTM C566 Moisture -Density Relations of Soils using a 4.54 kg (10 lb.) Rammer and a 457 mm (18 inches) Drop AASHTO T 180
514.4.2 -Contractor’s Quality Control: 514.4.2.1 -RCC Moisture Content: The Contractor shall perform moisture content tests in accordance with ASTM C566 on the initial batch of RCC produced each day and then once again if the ambient temperature reaches 85 °F or greater, as recorded in the vicinity of the concrete production facility.
514.4.2.2 -Testing for Opening Pavement to Traffic: A minimum of three sets of compressive strength specimens shall be made for each day’s paving operation. These compressive strength specimens shall be fabricated in accordance with ASTM C14 35, and under the direct observation of the Engineer. A set of specimens consists of three cylinders. Field cure the specimens in accordance with AASHTO T 23. Test one cylinder from each set of these cylinders for compressive strength in accordance wit h AASHTO T 22 at each of the following ages under the direct observation of the Engineer: 3 days, 5 days, and 7 days. The compressive strength of each set of cylinders shall be the average of the three specimens except that if one specimen shows evidence of improper sampling, molding, or testing, it shall be discarded and the remaining two strengths averaged. Should more than one specimen representing a given test show definite defects due to improper sampling, molding, or testing, the entire test shall b e discarded. The Contractor’s personnel who fabricate the compressive strength specimens shall provide evidence, prior to the start of construction and to the satisfaction of the Engineer, that they are proficient in the specified test methods.
293 RCC pavem ent at an age of 3, 5, or 7 days may be put into service if the average compressive strength test result of the set of cylinders at the corresponding age is at least 3,000 psi. The results of the 3 and 7 day quality control compressive strength tests sh all also be compared to the compressive strength results obtained in Section 514.3.2. If the compressive strength of these quality control specimens is less than 90% of the compressive strength results obtained in Section 514.3.2, the Contractor shall inv estigate the potential causes of the low strengths and report to the Engineer within 24 hours. If the compressive strength of these quality control specimens is less than 80% of the compressive strength results obtained in Section 514.3.2, and the compres sive strength is also less than 3,500 psi immediately stop production and notify the Engineer. Do not resume production until the cause of the discrepancy has been determined to the satisfaction of the Engineer. If the average strength of any of theses ets of quality control cylinders, representing a single day’s production, is equal to or greater than 4,000 psi, then the Contractor is not required to test any of the remaining quality control cylinders representing that day’s production.
514.4.2.3 -Density Testing: Field density tests for quality control shall be performed by the contractor as soon as possible, but no later than 30 minutes after the completion of the rolling. The in -place density and moisture content shall be determined using a properly maintained nuclear moisture -density gauge in accordance with the applicable provisions of MP 717.04.21. All testing shall be performed in direct transmission mode. Only wet density is used for evaluation. The testing shall be performed at a frequen cy not to exceed one test for every 1,000 yd2 placed. The required minimum density is 98 percent (98%) of the maximum laboratory density obtained according to AASHTO T 180 (Method D), as determined in Section
514.3.1The gauge will be calibrated for moi sture content at the beginning of the work
and at any time during the work. Any lot of RCC which was properly placed and compacted, but not meeting the density requirements based on the initial testing, can be further evaluated by obtaining five additiona l randomly located density tests within the lot in question. If the average of these five additional tests meets the required minimum density, the lot shall be considered acceptable. If the lot has been determined to not meet the specified minimum densit y requirements, it may be cored and tested by the Division in addition to any coring performed for acceptance as per Section 514.4.3.1. If the tested area achieves 3,500 psi, it will be paid at the full unit price. If the tested area indicates strength l ess than 3500 psi but greater than 3150 psi, payment will be made as set forth in Table 514.4.2.3.
TABLE 514.4.2.3 Compressive Strength
(percent of unit bid price) 3300 -3499 5 3150 -3299 15
If the cores indicate strengths less than 3150 psi at 28 days or longer, the Engineer will evaluate the results and may reject the affected area and require removal and replacement or elect to pay at a reduced rate.
294 514.4.3 -Acceptance Testing: 514.4.3.1 -Compressive Strength Tests for Acceptance: The compressive strength for acceptance of RCC will be determined by testing cores. The RCC shall be at least 28 days old before the cores are obtained. One four ( 4) inch diameter core shall be obtained, by the Division, for every 1,500 yd2 or fraction thereof of RCC placed and represent that area for acceptance purposes. These cores shall be tested by the Division for compressive strength. The minimum required compressive strength of these cores is 3,500 psi. The Contractor shall repair the core holes using concrete meeting the requirements of Areas of RCC represented by any cores not meeting the minimum compressive strength requirements shall be handled in accordance with Section 105.12. Such areas that are allowed to remain in place shall be paid for at a reduced unit bid price as outlined in Section
601.15.2, with the Design Strength being 3,500 psi
Additionally, as outline d in Section 514.4.2.3, cores may also need to be obtained to determine the compressive strength of any areas which are found to not meet the specified density requirements. It should be noted that lot sizes for density testing (1,000 yd2) and compressive strength acceptance testing (1,500 yd2) are different, and will overlap throughout the project. However, only one price adjustment shall be applied to any area not meeting the specification requirements. If any lot, or portion of a lot, is determined to have compressive strengths below 3,500 psi as outlined in Section 514.4.2.3 and is also found to be deficient in strength as outlined in Section 514.4.3.1, the price adjustment to be applied to that lot, or portion of that lot, shall be the greater of eit her the price adjustments calculated accordingly.
514.4.3.2 -Thickness Tests for Acceptance : The cores obtained in Section 514.4.3.1 shall be measured for thickness, in accordance with AASHTO T 148, prior to being tested for compressive strength. If the thickness of any core is found to be less than the specified design thickness, then an evaluation of the area represented by that core shall be performed by the Engineer in accordance with Section 105.12. If the Engineer allows that area of deficient thickness to remain in place, then that area shall be paid for at a reduced unit bid price as outlined in Table 514.4.3.2.
TABLE 514.4.3.2 Average Value of Pavement Thickness as Represented by Acceptance Core Unit Price as Percent of Contra ct Unit Price 0.1 to 1.0% Less than Specified Thickness 98.0% 1.1 to 2.0 % Less than Specified Thickness 96.0% 2.1 to 3.0% Less than Specified Thickness 94.0% 3.1 to 4.0% Less than Specified Thickness 92.2% 4.1 to 5.0% Less than Specified Thickness 90.3% 5.1 to 6.0% Less than Specified Thickness 88.4% 6.1 to 7.0% Less than Specified Thickness 86.5% More than 7.0% Less than Specified Thickness, with a maximum of 0.70 inches Less than Specified Thickness Remove and Replace