13045 P-501 PCC Flashcards
Questions
Answers
How long of a test section is required by the contract documents?
A: 300 ft
Name the four other topics covered by the P-501 spec other than PCC?
A: replacement of damaged and/or deficient soil cement stabilized base course, capping of underdrain trenches, concrete fill inthe trench above the longitudinal underdraing with low slump, low strength concrete.
At what frequency are gradations to be performed on stockpiled materials?
A: One per day for each material for each day of the stockpiling or production.
What are the limits for alkali-aggregate reaction in all aggregates, including sand and stone?
A: Expansion less than 0.08% at 14 days in the caustic soak solution in ASTM C1260 or less than 0.04% at one year in ASTM C1293 shall indicate that the aggregate is considered non-deleteriously reactive.
What is required when using aggregates at or above the limits of expansion?
A: Testing of the proposed concrete mix design to demonstrate control of deleterious expansion from ASR. Shall be either a modified version of ASTM C1260 or ASTM C1293.
What if expansions in the aggregate are less than 0.8% at 28 days in the caustic soak solution in the modified ASTM C1260 or less than 0.04% at two years in the modified ASTM C1293 test?
A: This shall be indicative of control of deleterious expansions from ASR.
Is lithium admixture required for the mix?
A: Yes, regardless of the level of aggregate reactivity.
How are aggregates to be tested for alkali-carbonate reaction and what if they are shown to be alkali-carbonate reactive?
A: ASTM C33 and they shall not be used.
What standards shall the natural sand (fine aggregate) comply with?
A: ASTM C33 and AASHTO M-6.
Name the gradation requirements for fine aggregate?
A: 3/8 in (100), N. 4 (95-100), N. 16 (45-80), N. 30 (25-55), N. 50 (10-30), N. 100 (2-10)
Name the standards that Coarse Aggregate must meet?
A: ASTM C33, AASHTO M80
What is the upper limit for the % of wear that the coarse aggregate may show in accordance with ASTM C131 and/or ASTM C535.
A: 47%
What type of cement is acceptable?
A: Portland cement, ASTM C150, Type I or Type II. Shall be low alkali type.
What is the upper limit for the alkali content in the cement?
A: 0.40%
Is cement salvaged from discarded or used bags acceptable?
A: No
What spec is the joint filler required to meet?
A: AASHTO M213
Is the use of more than one piece of joint filler acceptable?
A: Yes, when authorized by the engineer and must be held accurately to shape by stapling or other positive fastening means satisfactory to the engineer.
What specifications are dowel and tie bars required to meet?
A: AASHTO M 31 or AASHTO M 42
How much of the dowel bar is to be painted?
A: one-half
What specification is water required to meet?
A: AASHTO T-26
What if the intake for the water is shallow?
A: the intake shall be so enclosed as to exclude silt, mud, grass, or other foreign materials
What is the requirement for curing compound?
A:Must conform to ASTM C 309, type 2, class b.
What rate is curing compound to be applied at?
A: no more than 125 sq ft per 1 gallon.
Can admixtures be used if not approved by the Engineer?
A: no
What 2 types of Pozzolanic admixtures can be used?
A: Fly ash meting the requirements of ASTM C-350 or raw or calcined natural pozzolans meeting the requirements of ASTM C-402
What type of air-entraining admixtures are allowed?
A: those meeting the requirements of aASHTOM M 154 or ASTM C-260.
What is the acceptable air content?
A: 4% to 6% by volument of the concrete mixture as determined by ASTM C-231
What type of water-reducing, set-controlling admixture shall be used?
A: must meet requirements of ASTM C-494, Type A water reducer or Type D water reducing and retarding.
What is the difference between when type A water reducer should be used and when type D should be used?
A: A when temps are below 65 F and D when they are above.
What cannot be contained in the water reducer?
A: calcium chloride or chloride containing compounds as a functional ingredient.
What specification are lithium admixtures required to meet?
A: AASHTO Guide Specifications for Highway Construction, Section 56X, PCC Resistant to Exccessive Expansion from Alkali Silica Reaction, section 713.04
What quantity of lithium shall be required?
A: 0.6 gallons per cubic yard
What is the purpose of adding fly ash to the mixture?
A: to promote workability and plasticity.
How much fly ash shall be added to the mix?
A: 25% of the weight of total cementitious material
What spec is the fly ash required to meet?
A: ASTM C-618, Type F, except that the loss of ignition shall not exceed 3%. The fly ash should have a max of 1.5% alkali and a max of 6% CaO.
What is the minimum number of bags of cement required for the mix?
A: 5 1/2
What is the requirement for WWF?
A: Must meet AASHTO M-55 or M-221
How is the equipment approved prior to paving?
A: It must be on site prior to start of work for examination and approval.
Name the 3 types of equipment required at the batch plant for fine aggregate, each size of coarse aggregate and bulk cement (if used)?
A: bins, weighing hoppers, and scales
How should the bins and hoppers work?
A: they shall discharge efficiently and freely in the weighting hopper and means of control shall be provided so that, as the quantity desired in the weighing hopper is approached, the material may be added slowly and shut off with precision.
What level of accuracy are the scales required to be at?
A: They shall be accurate within 0.5% throughout their range of use
What is the contractor required to have on hand for testing of all scales?
A: Not less than ten 50-pound weights
Summarize requirements for mixers.
A: plate showing capacity of the drum in terms of vol of mixed concrete and the speed of rotation of the mixing drum, device determining the amount of air-entraining agent that is added to each batch requiring the admixture, and shall be examined daily for the accumulation of hard concrete or wear of the blades
When do the pickup and throwover blades in the drum need to be repaired or replaced?
A: when they are worn down 3/4 inch or more. blades shall be marked, must have manufacturers design on hand to show dimensions
What specification are truck mixtures required to meet?
A: AASHTO M 157
What specification are non-agitating hauling equipment required to meet?
A: AASHTO M 157
How many oscillating type transverse screeds are required for the finishing machine?
A: 2
What are the types of vibrators are acceptable?
A: surface pan type or internal type, immersed tube or multiple spuds
What frequency is required for the vibrators?
A: not less than 3,500 impulses per minute for surface type and not less than 5000 impulses per minute for tube vibrators and not less than 7000 per minute for spud vibrators. When used adjacent to forms, they shall have a frequency of not less than 3500 impulses per minute.
What is the sawcutter required to do after completing sawing?
A: Fllush out the slurry in the joint with water and install a backer rod slightly larger in diameter than the width of the saw cut
How thick are metal forms required to be? How long?
A: 7/32”, 10’ long