Crack the Code on your Concrete Delivery Ticket CONEXPO CON/AGG 3/6/2014

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Charla Bryant
7 years ago
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1 Crack the Code On Your Delivery Ticket Description: Every load of concrete comes with a delivery ticket that is full of useful information, if you know how to crack the secret code! Critical information includes identifying the right mix, batch and cumulative volume, help on checking yield, admixtures, and the amount of water that can be added within specs. The ticket also tells the batch time, which is important for predicting slump loss and setting time. Crack the Code On Your Delivery Ticket Delivery ticket full of useful information Have to crack the secret code! Identify right mix Batch and cumulative volume Help on checking yield Admixtures Amount of water that can be added Batch time to Predict slump loss and setting Crack the Code On Your Delivery Ticket Cost information Additional charges Responsibilities / Disclaimers Crack the Code On Your Delivery Ticket Take advantage of the information the concrete producer gives you to: 1. Make sure you got what you ordered. 2. Keep track of concrete volume and yield. 3. Predict setting time for your finishers kch7@cornell.edu 1

3 Cost Accounting Vol. This Load Cost per CY Total Batched this order

4 Cost Accounting Cost Accounting Cost per 2 CY Load Extra costs for this load Cost Accounting Cost Accounting Extra costs for this load Extra costs for this load IMPORTANT TERMS AND CONDITIONS IMPORTANT TERMS AND CONDITIONS Customer will be allowed Five Minutes Per Cubic Yard Free Unload Time. Delay Caused by Customer Over This Time Will Be Charge For At The Rate of $75.00 per hour. Extra charge is made for deliveries of less than 4 cubic yard loads. The cement used in this concrete is guaranteed to conform to the present specifications of the American Society for Testing Materials and the United States Government. Since we have no control over the use of the concrete we therefore cannot guarantee or assume responsibility for the finish work for which it is used. kch7@cornell.edu 4

5 Cost Accounting Cost Accounting Hot Water Small Load Extra costs for this load Arrived Job 2:50 (10 min early) Finished Pour 4:00 Total time 70 min. Allowed time per CY 5 min Number of CY 2 Total free discharge time 10 min Overtime by ticket 60 min Overtime by driver 45 min OT actually charged: 45 min OT Cost at $81.00/hr $60.75 Overtime Charges: 45 $81.00/hr = $60.75 Cost $ Extra Charges $ Total Charges $ Cost Accounting SO who agreed to these terms and conditions? 10 min haul time Who evidently not only agreed to the terms and conditions, but also inspected, approved, and What other exciting received the concrete! One busy and powerful stuff is on the top person! half of the ticket? kch7@cornell.edu 5

6 Now for the Bottom Half of the Ticket Composition Air Entrained Example Mix Cement 564 lb Water 259 Coarse #1 720 Coarse # Fine 1255 Total 3863 w/c = 259/564 = 0.46 ~½ inch ~1 inch 55 Type II Cement only, no Ash or Slag Water Reducer Air Entraining Admixture No Fibers kch7@cornell.edu 6

7 Composition Air Entrained Example Mix Cement 564 lb Water 259 Coarse 1785 Fine 1255 Total 3863 w/c = 259/564 = % 15% 7% Weight Proportions Who Cares about Batch Weights? 58 Who Cares about Batch Volumes? kch7@cornell.edu 7

9 Yield Batched by Weight Ordered, Discharged, Invoiced, and Complainedabout By Volume 1% concrete vol. per ton of aggregate/cy per 1% moisture 1. Approved batch weights. 2. Cement, flyash, slag, silica fume density. 3. Aggregate densities (specific gravities). 4. Aggregate moisture content. 5. Water already in mixer. 6. Added water 7. Air content But the owner will not load it with 11 CY by Volume Owner will calculate weight of material that should produce a volume of 11 CY 1% air volume = 1% concrete volume = 1 CY per 100 CY per percent air content. Yield = Measured Vol. as-delivered Predicted Vol. as-batched This concrete is batched by weight, but sold by volume. You can be assured of proper weight even though some settling of contents (loss of air) normally occurs during shipment and handling, and the water content and materials densities might be a bit different than we figured on. performance depends on relative volumes of constituents kch7@cornell.edu 9

10 Water Air Cement Sand Coarse Composition Air Entrained Example Mix Cement 564 lb Water 259 Coarse #1 720 Coarse # Fine 1255 Total 3863 w/c = 259/564 = 0.46 Cement 564 lb Water 259 Coarse 1785 Fine 1255 Total 3863 w/c = 259/564 = % 15% 7% Weight Proportions kch7@cornell.edu 10

11 Composition Air Entrained Example Mix Cement 564 lb Water 259 Coarse 1785 Fine 1255 Total 3863 w/c = 259/564 = % 11% 15% 78% Volume Proportions 6% 11% 15% 78% Volume Proportions 87 Cement 11% Water 15% Aggregate 78% Air 6% Fundamental Steps to Quality Low Water-Cement Ratio Wet Curing Temperature Control Hydration kch7@cornell.edu 11

12 Weight of Water Weight of Cement w/cm = Weight of Water Weight of Cement + SCM Type I Type I Type I Type Type I IASH The higher the w/c or w/cm, the more dilute the adhesive! 6000 Weight of Water Weight of Cement Type I Type I Type I 28-Day Compressive Strength Non Air-Entrained (about 2% air) Air-entrained concrete (about 6% air) Impact on Strength and Durability and ACI Code Requirements Water Cement Ratio Approximate 28-Day Compressive Strength as a function of Water/Cement Ratio. Adapted from ACI , Table 6.3.4(a) Coefficient of Permeability, Kq x 10, strperm Minimum specified strength Water Cement Ratio Permeability as a function of Water/Cement Ratio Data from Bureau of Reclamation Manual, 8th Edition, 1975, Figure 17, page Water / Cementitious Materials Ratio Average 28-day Compressive Strength (psi) Corrosion Protection Moist Freezing Strength-non air entrained Strength - air entrained Permeability Coefficient of Permeability E-14 m/sec kch7@cornell.edu 12

13 Water / Cement Ratio Water- Cement Ratio W / C = 0.70 Water / Cement Ratio Water / Cement Ratio W / C = 0.54 W / C = 0.42 Water / Cement Ratio W / C = 0.33 kch7@cornell.edu 13

14 Cement weight = 564 lb Water weight = 31 Gallons x 8,34 lb/gal. = 259 lbs Corrections for Aggregate Moisture Content w/c = 259/564 = Density depends on Moisture Content kch7@cornell.edu 14

15 Fine aggregate stock pile Older aggregate pile Recently dumped aggregate pile What does 6% Moisture Content Mean? Water Control ASTM, Industry Standard Usage: Weight of water IN and ON aggregate = 6% of Oven-Dry weight Common Ready-Mix Usage: Weight of water ON aggregate = 6% of SSD weight Day Compressive Strength Non Air-Entrained (about 2% air) Air-entrained concrete (about 6% air) Water Cement Ratio Approximate 28-Day Compressive Strength as a function of Water/Cement Ratio. Adapted from ACI , Table 6.3.4(a) Coefficient of Permeability, Kq x 10, % Increase in Permeability Water Cement Ratio kch7@cornell.edu 15

16 Analysis by Life lb cement / CY 122 lb Type F flyash 37 lb Silica Fume w/c ranges from 0.34 to in (50 mm) cover Northern Snowbelt Environment Compute time to corrosion Time to Corrosion Initiation Time to Corrosion Initiation Years w/c Time to Corrosion (Years) Gallons Water per CY Time to Corrosion Initiation 45 Time to Corrosion (Years) Years per gallon Gallons Water per CY kch7@cornell.edu 16

17 SettingTime Batch Time = 2:24 PM A Final Mystery CUMULATIVE BATCH WEIGHTS kch7@cornell.edu 17

18 Composition Air Entrained Example Mix Cement 564 lb Water 259 Coarse #1 720 Coarse # Fine 1255 Total 3863 w/c = 259/564 = 0.46 ~½ inch ~1 inch Batch weights / Load Batch weights /CY Why not double the weights for a 2 CY load??? Batch weights /CY Batch weights/load Batch weights /CY Batch weights/load kch7@cornell.edu 18

19 Crack the Code On Your Delivery Ticket Take advantage of the information the concrete producer gives you to: 1. Make sure you got what you ordered. 2. Keep track of concrete volume and yield. 3. Predict setting time for your finishers kch7@cornell.edu 19

Example Specification for Concrete using Current Building Code Requirements

Example Specification for Concrete using Current Building Code Requirements DISCLAIMER: This specification is an example that accompanies a seminar titled The P2P Initiative: Performance-based Specs for