13045 P-501 PCC Flashcards
1
Q
Questions
A
Answers
2
Q
How long of a test section is required by the contract documents?
A
A: 300 ft
3
Q
Name the four other topics covered by the P-501 spec other than PCC?
A
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.
4
Q
At what frequency are gradations to be performed on stockpiled materials?
A
A: One per day for each material for each day of the stockpiling or production.
5
Q
What are the limits for alkali-aggregate reaction in all aggregates, including sand and stone?
A
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.
6
Q
What is required when using aggregates at or above the limits of expansion?
A
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.
7
Q
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
A: This shall be indicative of control of deleterious expansions from ASR.
8
Q
Is lithium admixture required for the mix?
A
A: Yes, regardless of the level of aggregate reactivity.
9
Q
How are aggregates to be tested for alkali-carbonate reaction and what if they are shown to be alkali-carbonate reactive?
A
A: ASTM C33 and they shall not be used.
10
Q
What standards shall the natural sand (fine aggregate) comply with?
A
A: ASTM C33 and AASHTO M-6.
11
Q
Name the gradation requirements for fine aggregate?
A
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)
12
Q
Name the standards that Coarse Aggregate must meet?
A
A: ASTM C33, AASHTO M80
13
Q
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
A: 47%
14
Q
What type of cement is acceptable?
A
A: Portland cement, ASTM C150, Type I or Type II. Shall be low alkali type.
15
Q
What is the upper limit for the alkali content in the cement?
A
A: 0.40%
16
Q
Is cement salvaged from discarded or used bags acceptable?
A
A: No
17
Q
What spec is the joint filler required to meet?
A
A: AASHTO M213
18
Q
Is the use of more than one piece of joint filler acceptable?
A
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.
19
Q
What specifications are dowel and tie bars required to meet?
A
A: AASHTO M 31 or AASHTO M 42
20
Q
How much of the dowel bar is to be painted?
A
A: one-half
21
Q
What specification is water required to meet?
A
A: AASHTO T-26
22
Q
What if the intake for the water is shallow?
A
A: the intake shall be so enclosed as to exclude silt, mud, grass, or other foreign materials
23
Q
What is the requirement for curing compound?
A
A:Must conform to ASTM C 309, type 2, class b.
24
Q
What rate is curing compound to be applied at?
A
A: no more than 125 sq ft per 1 gallon.
25
Can admixtures be used if not approved by the Engineer?
A: no
26
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
27
What type of air-entraining admixtures are allowed?
A: those meeting the requirements of aASHTOM M 154 or ASTM C-260.
28
What is the acceptable air content?
A: 4% to 6% by volument of the concrete mixture as determined by ASTM C-231
29
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.
30
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.
31
What cannot be contained in the water reducer?
A: calcium chloride or chloride containing compounds as a functional ingredient.
32
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
33
What quantity of lithium shall be required?
A: 0.6 gallons per cubic yard
34
What is the purpose of adding fly ash to the mixture?
A: to promote workability and plasticity.
35
How much fly ash shall be added to the mix?
A: 25% of the weight of total cementitious material
36
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.
37
What is the minimum number of bags of cement required for the mix?
A: 5 1/2
38
What is the requirement for WWF?
A: Must meet AASHTO M-55 or M-221
39
How is the equipment approved prior to paving?
A: It must be on site prior to start of work for examination and approval.
40
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
41
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.
42
What level of accuracy are the scales required to be at?
A: They shall be accurate within 0.5% throughout their range of use
43
What is the contractor required to have on hand for testing of all scales?
A: Not less than ten 50-pound weights
44
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
45
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
46
What specification are truck mixtures required to meet?
A: AASHTO M 157
47
What specification are non-agitating hauling equipment required to meet?
A: AASHTO M 157
48
How many oscillating type transverse screeds are required for the finishing machine?
A: 2
49
What are the types of vibrators are acceptable?
A: surface pan type or internal type, immersed tube or multiple spuds
50
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.
51
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
52
How thick are metal forms required to be? How long?
A: 7/32", 10' long
53
The top face of the form shall not vary from a true plane by more than what amount in 10 feet?
A: 1/8"
54
How many pins are required per form?
A: 3
55
What is the requirement for forms?
A: They shall not vary from a true line by more than 1/4 in at any point.
56
What is the maximum thickness for stockpile layers?
A: 3ft
57
Can aggregates from different sources be stockpiled together?
A: No
58
How long must aggregates be stockpiled or binned if they are washed or handled by hydraulic methods?
A: 12 hours
59
How much cement is considered one sack?
A: 94 lbs
60
What are the weight tolerances for cement and aggregates?
A: 1% for cement and 2% for aggregates
61
What is the accuracy required for measuring of water?
A: +/- 1% of required amount
62
What is the accuracy required for measuring admixture?
A: +/- 3%
63
What are the strength requirements for the mix?
A: 650 flex at 28 days and 735 at 90 days
64
What are the max and min slump for the mix?
A: 1 1/2" max and 1/2" min
65
What are the max and min of the air content?
A: 4% to 6%
66
What is the max slump if the mix is not placed by slip form paving?
A: 2 1/2"
67
What are the air and slump requirements for the low strength concrete?
A: 1" to 2" slump, 5% to 7% air and a 7 day compressive strength of 2000psi.
68
What tests are required during the mix design process?
A: gradation, specific gravity, fineness modulus, dry rodded unit weight, abrasion, compressive and tensile strengths of cement, slump, air, yield, strength, time of set, shrinkage, and statistical analysis.
69
How many beams are required to be made and at what frequency?
A: 7 beams for each 200 cubic yards. Broken at 3, 7, and 28 days
70
At what point can the frequency of beam making be modified to one set per 500 CY?
A: after maturity meter curves have been developed to an acceptable level
71
What is the equation for thickness adjustment if strengths come back low?
A: f (adjusted) = t^2 (actual)/t^2 (design) * f(actual)
72
What if the deficiency is below 625 psi?
A: must be removed or, if approved by the engineer, may be left in place without payment.
73
What specification is required to be met for ready-mixed concrete?
A: AASHTO M-157
74
What's the max and min mixing time and when does it start?
A: It starts when all materials, except water, are emptied into the drum and time ends when the discharge chute opens. Max is 90 seconds, min is 50 seconds
75
What is the time limit for concrete transport?
A: 30 minutes when the concrete is hauled in nonagitating trucks, 60 minutes when hauled in truck mixers
76
At what temperature shall concreting operations be discontinued?
A: descending air temp is 40 degrees and shall not be resumed until heat reaches 35 degrees
77
What are the max and min temps for concrete in cold weather concreting?
A: 50 F and 80 F
78
What are the max and min temps for aggregates and water in cold weather concreting?
A: 70 and 150
79
How long shall concrete be protected in cold weather?
A: 5 days
80
What is the max temp for hot weather concrete?
A: 85 F
81
What tool shall be used for hand spreading?
A: shovels, not rakes
82
What is the max that a vibrator can be operated in one location?
A: 15 seconds
83
What is the allowable variance for joints?
A: 1/4"
84
What is the allowable variance across joints using a 10 ft straight edge?
A: 1/8"
85
What is the spacing on the dowels?
A: 12in
86
Shall deformed dowels be painted, greased, or enclosed in sleeves?
A: No
87
When shall the joints be cut in the concrete?
A: joints shall be cut the the time and in the manner approved by the Engineer
88
What is the size of the greencut sawcut?
A: 1/8" wide
89
When can wooden forms be used?
A: When approved by the Engineer
90
What is the maximum variation allowed in the joints within 10 ft?
A: 1/4"
91
What shall the thickness of the concrete be increased to at an expansion joint?
A: 25% of the normal pavement thickness to the nearest in but not less than 2 in sloped to nrmal thickness in not less than 10 ft from the joint
92
When are construction joints required?
A: when work is suspend for more than 30 minutes.
93
Name the sequence for operations for finishing.
A: strike-off and consolidation, floating and removal of laitance, straightedging, and final surface finish.
94
What types of finish will be acceptable?
A: belt finish or burlap drag
95
What is the maximum variation in elevation from finished grade that is allowed?
A: 1/4"
96
In which direction shall the screed always be moving?
A: In the direction in which the work is progressing
97
Name the two conditions in which hand finishing is allowed.
A: 1) breakdown of mechanical equipment, 2) Narrow widths or areas or irregular dimensions where operation of the mechanical equipment is impractical
98
Name the three steps required for hand finishing/
A: 1) Concrete shall be struck off and acreeded. 2) the screed shall be at least 2 ft. longer than the max width of the slab, sufficiently rigid, and shall be metal shod with metal, 3) Consolidation shall be attended by the use of a vibrator
99
Name the 3 floating methods?
A: 1) Hand Method, 2) Mechanical Method 3) Alternative Mechanical Method
100
What size shall the hand operated float be?
A: 12 ft in length and 6 in in width
101
Describe the motion by which the hand float shall be worked?
A: Sawing motion and passing gradually from one side of the pavement to the other. Forward movement along the centerline of the pavement shall be in successive advances of not more than one-half the length of the float. Excessive water shall be wasted over the side.
102
Name the steps/requirements of mechanical float?
A: 1) Approved by engineer, 2) tracks shall be accurately adjusted to the required crown 3) adjusted and coordinated with the adjustments carried ahead of the float at all times, 4) speed shall be adjusted so the float will lap distance specified by the engineer 5) float shall pass over at least 2 times, but not excessive
103
When are hand floats with shorter blades allowed?
A: Preceding the main floating operation, floats with blades of 5 ft in length and 6 in in width may be used to smooth and fill in open-textured areas
104
What type of testing is required after the floating has been completed and the concrete is still plastic?
A: 16ft straightedge, advancing the straightedge no more than one-half the width of the slab
105
What two types of final finish are allowed?
A: Belt finish and burlap drag finish
106
What type of material is required for a belt finish?
A: 2-ply canvas belt not less than 8 inches wide and at least 3 ft longer than the pavement width.
107
Describe the material and motion required for a drag finish?
A: a seamless strip of damp burlap shall be dragged longitudinally along the full width of the pavement. at least 3 feet wide should be in contact with the full width of the pavement surface while the drag is used. Shall consist of two layers of burlap with the bottom layer approximately 6 inches wider than the upper layer.
108
At what width of pavement is a bridge required for the burlap drag?
A: 16 ft
109
What is the maximum depth of groove that can be created with a burlap drag?
A: 1/16"
110
According to P-501, at what point is edging required?
A: before the concrete has taken its initial set, the edges shall be worked with an approved tool and rounded to the radius required by the plans.
111
Describe the 2 concrete surface testing methods required after concrete has hardened sufficiently.
A: 1) a GOMACO Smoothness Indicator (GSI) shall be set up to profile as a California Profilograph. 2) The contracctor shall have a 16' rolling straightedge
112
What is the maximum Roughness Index Value for the GSI?
A: Shall not exceed five inches per mile for each 500 linear foot section mased on a blanking band of 2/10" at time of placement & individual bumps or depressions shall not exceed 3/10" per 25 feet.
113
What is the maximum surface deviation for the 16' straightedge?
A: 1/4" in 16 ft, >1/2" will be cause for removal
114
When removing an area of pavement, what is the minimum width that will be allowed to be left in place?
A: 10ft
115
What is the max amount of time the concrete may be left unexposed between stages of curing and during the curing period?
A: 30 mins
116
Describe the method by which curing compound shall be applied.
A: By mechanical sprayers under pressure at the rate of 1 gal to not more than 125 sq ft.
117
What type of spraying equipment is required for curing compound?
A: Fully atomizing type equipped with a tank agitator.
118
Should curing compound be applied to the inside faces of joints to be sealed?
A: No
119
What shall be done as soon as side forms are removed?
A: sprayed with curing compound
120
What special requirements are there for curing when the average daily temp is below 40 F?
A: blanketing material shall be provided. The engineer shall determine the time period.
121
How soon can forms be removed from the fresh concrete?
A: not until concrete has set for at least 12 hours
122
If an area has to be removed, what is the minimum size of the section to be removed?
A: 10 ft in length nor less than the full width
123
What strength is required for dowel drilling?
A: 450 psi
124
What strength is required for paving equipment?
A: 500 psi
125
What strength is required for opening to air traffic?
A: 650 psi
126
Who decides when the pavement shall be opened?
A: Engineer based on maturity meter readings and/or flex testing.
127
After the pavement has been placed, how many days are required, minimum, for opening the pavement to traffic?
A: 3 days
128
Describe the 3 surface tolerances that the pavement must pass in order to be acceptable?
A: 1) lateral deviation from established alignment of the pavement edge shall not exceed plus or minus 0.10 foot in any lane, 2) vertical deviation shall not exceed plus or minus 0.04 ft at any point, 3) surface smoothness deviations shall not exceed 1/4" from a 16 foot straightedge
129
How many cores are required for pavement thickness tolerance testing?
A: 1 per 250 ft per lane per section, to verify thickness and consolidation
130
If strength is adjusted based on thickness, what is the minimum strength acceptable and what happens if it below this strength?
A: 625 psi and it shall be removed and replaced or left in place without payment as determined by the engineer.
