Concrete Mixing Technology Comparison

Water Usage Calculations:

Drums:

According to CSA 5.2.3.2, "The entire contents of the mixer shall be discharged before recharging". This could be understood to mean that the drum should be clean and free of all materials from the previous batch, which requires washing and removing all the wash water from the previous batch. This means wash water is required for every batch of concrete.

Calculations - 200 gallons of water to wash out drum, 7 cubic metre loads, 10,000 cubic meters of concrete = 1,082,857 litres of wash water.

Omni-Mixing Technology:

Assumptions - 10,000 cubic metre project, 500 metres per day over 3-4 hours, 60L per washout.

Calculations - 60L per washout x 20 days x 2 mixers = 2,400 litres of wash water

Volumetric:

Calculations - 60L per washout x 20 days x 8 mixers = 9,600 litres of wash water

Diesel Fuel Calculations:

Drums:

Assumptions - Batch plant located 25 minutes from project, 500 cubic metres per day, non-paved roads, 13L per 100hp/hour fuel consumption on a diesel engine, 33 drum trucks to meet 160m3/hr production, 84 minute round trip to project (5 minutes to batch, 12 minutes to mix, 25 minutes to the project, 5 minute wait, 5 minutes unload, 7 minute washout, 25 minute back to the batch plant), 350 hp engine running at 70% for the round trip.

Calculations - 33 drum trucks x 4.25 hours x(13L per 100 hp / hour x 3.5 hp x 70%) x 20 days = 89,339.25 litres of diesel fuel

*does not include loaders, generators, chillers, or the batch plant. At a batch plant 40-60 minutes away this fuel consumption doubles

Omni-Mixing Technology:

Assumptions - 13L per 100 hp/hour fuel consumption on a diesel engine, Engine running at 100 hp for mixing, 500 cubic metres per day.

Calculations - 4.25 hours x 13 L per 100 hp/hr x 2 mixers x 20 days= 2,210 litres of diesel fuel

Volumetric:

Assumptions - 13L per 100 hp/hour fuel consumption on a diesel engine, Engine running at 100 hp for mixing, 500 cubic metres per day.

Calculations - 4.25 hours x 13 L per 100 hp/hr x 8 mixers x 20 days= 8,840 litres of diesel fuel

CO2 Production Calculations:

Drums:

Assumptions - EIA states, "22.4 pounds of CO2 per gallon of diesel fuel burned", 5-10% waste at CO2List calculations of 1.4 tonnes per cubic metre of concrete excluding washout and recycling, fuel consumption from previous calculation assumptions.

Calculations - 89,339.25L of diesel fuel/3.78 x 22.4 pounds = 529,417.8 / 2.2 = 240,644.4 kg or 241 tonnes of CO2

Waste concrete at 5% adds an additional = 5,000 cubic metres x 1.4 tons = 7,000 tonnes

Waste concrete at 10% adds an additional = 10,000 cubic metres x 1.4 tons = 14,000 tonnes

Totals - 241 tonnes + (700 to 1400 tonnes) = 941 tonnes to 1641 tonnes of CO2

*does not include loaders, generators, chillers, or the batch plant.

Omni-Mixing Technology:

Calculations - 2200 L of diesel fuel/3.78 x 22.4 pounds = 13,096 / 2.2 = 5,950 kg or 5.95 tonnes of CO2

Volumetric:

Calculations - 8840 L of diesel fuel/3.78 x 22.4 pounds = 52,385.18/ 2.2 = 23,811.48 kg or 23.81 tonnes of CO2

Tonne Movements Calculations:

Drums:

Roughly 23,000 tonnes of aggregates are needed to produce 10,000 cubic metres of concrete. Aggregates must be delivered into the batch plant then transported out of the batch plant to the site in drums. Assuming 5-10% waste concrete is sent and returned from site due to being rejected for slump, air, or temperature and must be resent to site.

Calculation - 23,000 x 2 = 46,000 tonnes + (5%to 10% x 23,000 tonnes x 2 for each way) = 48,300 tons to 50,600 tonnes

Omni-Mixing Technology:

Aggregates delivered directly to site where they are loaded continuously into mixers.

= 23,000 tonnes

Volumetric:

Aggregates delivered directly to site where they are loaded continuously into mixers.

= 23,000 tonnes

Production Rates Calculations:

Drums:

Assumptions - 1.5 hour cycle time, 500 cubic metres per day, 7 cubic metre drums.

= 33 mixers are required to achieve 160 m3/hour continuously.

Omni-Mixing Technology:

2 mixers are required to achieve 160 m3/hour continuously.

Volumetric:

8 mixers are required to achieve 160 m3/hour continuously

Redundancy Calculations:

Drums:

A second batch plant is required to have redundancy in case the primary batch plant goes down during production. No extra mixers are required to achieve redundancy.

= 2 Batch Plants

Omni-Mixing Technology:

If one mixer goes down the pour can be finished with the second mixer at slower production speeds.

= No extra mixers required to achieve redundancy

Volumetric:

If one mixer goes down the pour can be finished with the other mixers at slower production speeds.

= No extra mixers required to achieve redundancy

Man Hours Calculations:

Drums:

A batch plant will require 1 dispatch, 2 loader operators, 2 batch-man, 33 drum drivers = 38 workers

Assuming 4.25 hour days, 20 days.

Calculations - 38 x 4.25 x 20 = 3,230 hours

Omni-Mixing Technology:

2 loader operators, 2 operators, 1 floater = 5 workers

Assuming 4.25 hour days, 20 days.

Calculations - 5 x 4.25 x 20 = 425 hours

Volumetric:

2 loader operators, 8 operators, 1 floater = 11 workers

Assuming 4.25 hour days, 20 days.

Calculations - 11 x 4.25 x 20 = 935 hours

Quality and Temperature Gain Calculations:

Drums:

Historical industry averages from drum companies.

CSA defines a mass pour anything over 1m thick. A windmill project would be defined as a mass pour meaning temperature is extremely important and concrete must be delivered below 20 degrees Celcius according to CSA.

At an ambient temperature of 25 degrees C, 20 degree C aggregates, 8 degree C water with a 20 minute distance from site concrete in a drum would be at 31 degrees C. Therefore, risk of detrimental concrete temperatures is a high risk.

Potential concrete problems due to high concrete temperatures include:

• Increased water demand
• Increased rate of slump loss
• Increased rate of setting
• Increased tendency for plastic-shrinkage cracking
• Increased difficulty in controlling entrained air content
• Decreased 28-day and later strengths
• Increased tendency for differential thermal cracking
• Greater variability in surface appearance
• Increased permeability

Omni-Mixing Technology:

Historical performance is a positive indicator of future performance. Our past performance with 3rd party testing and in-house testing (1000s in total) is as follows:

2018 to date – 100%,

2017 – 100%,
2016 – 100%,
2015 – 100%,
2014 – 100%,
2013 – 100%,
2012 – 100%,
2011 – 100%,
2010 – 99% (we had one cylinder break at 29.6 MPa on a 30 MPa specification in June 2010).

(We have very detailed records of our performance and would be happy to show you proof or direct you to engineering firms who have used us.)

At an ambient temperature of 25 degrees C, 20 degree C aggregates, 8 degree C water our concrete would be at 19 degrees C.

Fresh concrete has no risk of temperature gain.

Volumetric:

A very experienced operator on each of the 8 mixers will be able to produce at a high quality with no performance issues.

Fresh concrete has no risk of temperature gain.