ACI Concrete Field Testing Technician Grade 1 Study Guide Graded A Q&A Complete

ASTM C31 / C31M-06 - Standard Practice for Making, Curing, Protecting & Transporting Test Specimens in the Field Conditions. ASTM C1064 /C1064M-05 - Standard Test Method for Temperature of Freshly Mixed HydraulicCement Concrete ASTM C172 -07 - Standard Practice For Sampling Freshly Mixed Concrete From Different Containers Used In The Production or Transportation Of Concrete. ASTM C143 / C143M-05a - Standard Test Method for Slump of Hydraulic-Cement Concrete Both In Laboratory And In The Field ASTM C138 / C138M-07 - Standard Test Method for Density (Unit Weight), Yield, and Air Content (Gravimetric) of Concrete ASTM C231 -04 - Standard Test Method for Air Content of Freshly Mixed Concrete by Pressure Method ASTM C173 / C173M-07 - Standard Test Method For Air Content of Freshly Mixed Concrete Containing Any Type Of Aggregate, Whether It Be Dense, Cellular, or Lightweight by Volumetric Method Molds - Mold for specimens shall be made of steel, cast iron, or other nonabsorbent material, nonreactive with concrete. Molds shall be watertight and hold their dimensions and shape under all conditions of use. Cylindrical Specimens - Compressive or Splitting Tensile Strength Specimens shall be cylinders cast and allowed to set in an upright position. The length shall be twice the diameter (4 X 8in or 6 X 12 in). The cylinder daimeter shall be at least 3 times the nominal maximum size of the coarse aggregate. Whenthe nominal maximum size of the coarse aggregate exceeds 2 inches the concrete sample shall be treated by wet sieving through a 2 inch sieve. Beam Specimens - Flexural strength specimens shall be beams of concrete cast and hardened in the horizontal position. The length shall be at least 2 inch greater than three times the depth as tested. The ratio of width to depth as molded shall not exceed 1.5. The standard beam shall be 6 by 6 inches in cross section, and shall be used for concrete with nominal maximum size coarse aggregate up to 2 inches. When the nominal maximum size of the coarse aggregate exceeds 2 inches, the smaller cross sectional dimension of the beam shall be at least three times the nominal maximum size of the coarse aggregate. Tamping Rod - A round, straight steel rod having the tamping end or both ends rounded to a hemispherical tip of the same diameter as the rod. Rod Dimensions are based off of the diameter of Cylinder or Width of Beam. - less than 6 inch, Rod =Diameter 3/8 inch & Length 12inch - 6 inch, Rod = Diameter 5/8 inch & Length 20 inches - 9 inch, Rod = Diameter 5/8 inch & Length 26 inches [Rod tolerances length + or - 4inches and diameter + or - 1/16inch.] Vibrators - Internal vibrators shall be used. The vibrator frequency shall be at least 9000 vibrations per minute while the vibrator is operating in the concrete. The diameter of a round vibrator shall be no more than one fourth the diameter of the cylinder mold or width of the beam mold. The combined length of the vibrator shaft and vibrating element shall exceed the depth of the section being vibrated by at least 3 inches. Mallet - A mallet with a rubber or rawhide head weighing 1.25 + or - 0.5 lb shall be used. Sampling Receptacle - The receptacle shall be a suitable Heavy Gage metal pan, wheelbarrow, or flat, clean nonabsorbent board of sufficient capacity to allow easy remixing of the entire sample with a shovel or trowel. Temperature Measureing Device - Shall be capable of accurately measuring the temperature 3 inches or more immersion of the freshly mixed concrete to plus or minus 1 degree Fahrenheit throughout the range of 30 - 120 degrees Feahrenheit. The device shall be readable and accurate to plusor minus 0.5 Feahrenheit. Verification of direct reading resistance reference temperature measuring devices shall be performed every twelve months. ASTM C1064 Standard Test Method for Temperature Procedure - - Sample the freshly mixed concrete in accordance with Practice C172 - Position the temperature measuring device so that the end of the temperature sensing portion is submerged 3 inches and at least 3 inches of concrete cover in all directions. - Close all voids at surface of the concrete around the temperature device. - Leave the temperature measuring device in the concrete for at least 2 mins but no more than 5 mins. -Then read and record to the nearest 1 degree Feahrenheit. ASTM C172 Standard Test Method For Section 40: - - The elapsed time shall not exceed 15 mins. between obtaining the first and final portions of the composite sample. - The sample shall be combined and remixed with a shovel to ensure uniformity. -Sample size is dictated by the maximum aggregate size and should be atleast 28 L (1cubic foot) for strength tests. -Start the test for slump, temperature, and air content within 5 mins. after obtaining sample. -Start molding specimens for strength tests within 15 mins. after obtaining the sample. ASTM C172 Sampling from Stationary Mixers - - Sample the concrete by collecting two or more portions taken at regularly spaced intervals during discharge of the middle potion of the batch within 15 mins. Do Not obtain portions of the composite sample from the very first or last of the batch discharge. Perform sampling by passing a receptacle completely through the discharge stream, or by completely diverting the discharge into a sample container. These requirements apply to both tilting and non-tilting mixers. ASTM C172 Sampling from Paving Mixers - -Sample the concrete after the contents of the paving mixer have been discharged. Obtain samples from at least five different portions of the pile and combine them into one composite sample for test purposes. Avoid contamination with sub-grade material by discharging a sample of the concrete in three shallow containers on the sub-grade. Combine the samples to obtain one composite sample for test purposes. The containers shall be of a size sufficient to provide a composite sample size that is in agreement with the maximum aggregate size.ASTM C172 Sampling from Revolving Drum Truck Mixers or Agitators - - Sample the concrete by collecting two or more portions taken at regularly spaced intervals during discharge of the middle portion of the batch. The samples should be obtained within 15 mins and combine them into one composite sample for test purposes. In any case do not obtain samples until all of the water and any admixtures have been added to the mixer, also do not obtain samples from the very first or last portions of the batch discharge. Sample by repeatedly passing a receptacle through the entire discharge stream or by completely diverting the discharge into a sample container. ASTM C143 Slump Section 3 & 4 - A sample of mixed concrete is placed and compacted by rodding in a mold shaped as the frustum of a cone. The mold is raised and the concrete is allowed to subside. The Vertical Distance Between The Original and Displaced Position of the Center of the Top Surface of the concrete is measured and reported as the slump of the concrete. This test method is considered applicable to plastic concrete having coarse aggregate up to 1.5 inches in size. Wet-Sieve all aggregates that are larger than 1.5 inches. Concrete having less than .5 inches may not be adequately plastic and concretes having slumps greater than about 9 inch may not be adequately cohesive for this test to have significance. Mold for Slump Test - The test specimen shall be formed in a mold made of metal not readily attacked by cement paste free from dents, deformation or adhered mortar. The mold shall be in the form of the lateral surface of the frustum of a cone with the base 8 inches in diameter, the top 4 inches in diameter, and the height 12 inches with a tolerances of 1/8 of an inch. The base and the top shall be open and parallel to each other and at right angles to the axis of the cone. The mold shall be provided with foot pieces and handles. The mold shall be constructed without a seam. The interior of the mold shall be relatively smooth and free from projections. Check mold conformance to specified dimensions when it is purchased and once a year. ASTM C143 Slump Procedure - - Dampen Slump Equipment and place it on a rigid, flat, level moist, nonabsorbent surface, free of vibration and that is large enough to contain all of the slumped concrete. - The cone shall be held firmly in place during filling and perimeter cleaning by operator standing on foot pieces or by a clamping arrangement. - Immediately fill the mold in three layers, each approximately one third the volume of the mold. -Move scoop around the perimeter of the mold opening to ensure an even distribution of the concrete. -Rod each layer 25 times with vertical strokes spirally towards the center with each upper layer penetrated 1". -Top Layer must be above the mold before rodding is started. Add additional concrete if the concrete fall below the top edge of the mold to keep an excess of concrete above the top of mold at all times.- Strike off the surface of the concrete by means of a screeding and rolling motion of the tamping rod. -Raise the mold vertically a distance of 12 inches in 5 + or - 2 seconds by a steady upward lift. - Measure the slump by determining the vertical difference between the top of the mold and the displace original center of the top surface of the specimen. Report the slump to the nearest one fourth inch. - If a decided falling away or shearing off of concrete from one side or portion of the mass occurs disregard the test and make a new test on another portion of the sample. -Test should be completed in 2.5 minutes Measure - A cylindrical container made of steel or other suitable metal. The capacity of the measure is based on the nominal size of aggregate in the concrete. Capacity Of Measures: 1"agg. - 6L, 2"agg. -14L & 3"agg. - 28L