TB-1402 — Using V-MAR® 3 (Rheology Modifying Admixture) to Reduce Concrete Pump Pressure Technical Bulletin

The successful pumping of concrete is dependent on a number of factors including having a suitable concrete mix. Fine, naturally rounded sand is ideal for producing pumpable concrete, but as the supply of fine, naturally rounded sand decreases, concrete producers are forced to utilize materials such as manufactured sands that are often coarse, angular, and gap-graded. Use of these materials can lead to segregation while pumping, and increased pump pressure. The fundamental reason coarse angular sands do not perform as well as naturally-rounded sand is due to their inability to “flow” within the concrete matrix.

V-MAR® 3 has a unique polymeric structure that, under the influence of energy (e.g. vibration or pumping), aligns itself and allows coarse angular sand to flow similarly to naturally-rounded sand. At this point the polymers slide over each other in the direction of flow and reduce the yield stress of the concrete, essentially lubricating the pump hose, reducing internal friction, and reducing the pressure necessary to pump the concrete. As energy is removed, the polymers interlock leaving the concrete as it was before movement. V-MAR® 3 has been shown to have a neutral effect on most concrete properties, as evidenced by the setting time, air entrainment, and compressive strength data in Table 1 below.

Table 1 – Neutral Effect of V-MAR 3 on Concrete Properties (SI Units)

Cement, kg/m3 335 335 335 335 335
Stone, kg/m3 798 798 798 798 798
Total Sand, kg/m3 1026 1026 1026 1026 1026
Total Mix Water, kg/m3 193 193 193 193 193
HRWR Admixture, mL/100 kg 300 300 300 300 300
V-MAR 3, mL/100 kg 60 110 170 220
Air, % 1.1 1.5 1.3 1.4 1.6
Initial Set, hrs:min 4:10 3:55 4:10 4:15 4:25
Compressive Strength @ 1 Day, MPa 11.0 10.3 10.9 10.9 10.8
Compressive Strength @ 7 Days, MPa 24.5 25.4 24.9 26.3 27.9
Compressive Strength @ 28 Days, MPa 31.2 32.7 32.5 33.1 35.6

 

Table 1 – Neutral Effect of V-MAR 3 on Concrete Properties (English Units)

Cement, lb/yd3 564 564 564 564 564
Stone, lb/yd3 1345 1345 1345 1345 1345
Total Sand, lb/yd3 1730 1730 1730 1730 1730
Total Mix Water, lb/yd3 325 325 325 325 325
HRWR Admixture, oz/cwt 4.6 4.6 4.6 4.6 4.6
V-MAR 3, oz/cwt 0.9 1.7 2.6 3.4
Air, % 1.1 1.5 1.3 1.4 1.6
Initial Set, hrs:min 4:10 3:55 4:10 4:15 4:25
Compressive Strength @ 1 Day, lb/in.2 1600 1500 1580 1580 1560
Compressive Strength @ 7 Days, lb/in.2 3560 3680 3610 3820 4040
Compressive Strength @ 28 Days, lb/in.2 4530 4740 4720 4800 5170

The following examples show how the incorporation of manufactured sand in pumped concrete was made possible by utilizing V-MAR 3 as a pumping aid. The addition of V-MAR 3 to the concretes led to pump pressures being maintained at levels equal to or below the pressures produced by the control concrete, which did not contain manufactured sand.

It must be noted that these are examples only. The use of manufactured sand from different sources and/or in different amounts will have different effects on pumping pressure, and the V-MAR 3 requirements will also vary. Tests must be conducted on the various mix designs, replacement amounts of manufactured sand, and dosage rates of V-MAR 3 before the start of a project. An improper mix design, although pumpable, may still be harsh and difficult to place.

Example 1 – Portland Cement Concrete (SI Units)

Manufactured Sand Content 0% 40% 40% 60% 60%
Cement, kg/m3 274 282 272 275 271
Stone, kg/m3 964 979 957 946 955
Total Sand, kg/m3 883 905 914 921 907
Total Mix Water, kg/m3 196 201 201 206 201
WR Admixture, mL/100 kg 190 190 190 190 190
V-MAR 3, mL/100 kg 185 185
Slump, mm 114 95 127 114 127
Air, % 1.1 0.8 0.8 0.8 0.8
Pump Pressure, MPa 6.5 7.6 6.5 10.9 4.8

 

Example 1 – Portland Cement Concrete (English Units)

Manufactured Sand Content 0% 40% 40% 60% 60%
Cement, lb/yd3 462 475 459 464 457
Stone, lb/yd3 1625 1651 1613 1594 1611
Total Sand, lb/yd3 1488 1526 1542 1553 1530
Total Mix Water, lb/yd3 330 338 340 347 339
WR Admixture, oz/cwt 3 3 3 3 3
V-MAR 3, oz/cwt 2.8 2.8
Slump, in. 4.50 3.75 5.00 4.50 5.00
Air, % 1.1 0.8 0.8 0.8 0.8
Pump Pressure, lb/in.2 950 1100 950 1580 700

Example 2 – Portland Cement/Fly Ash Concrete (SI Units)

Manufactured Sand Content 0% 40% 40% 60% 60% 80%* 80%*
Cement, kg/m3 248 248 252 253 243 246 244
Fly Ash, kg/m3 65 65 66 66 64 66 64
Stone, kg/m3 967 968 970 939 926 917 922
Total Sand, kg/m3 887 899 880 926 926 931 935
Total Mix Water, kg/m3 178 181 180 177 182 180 186
WR Admixture, mL/100 kg 260 260 260 260 260 260 260
V-MAR 3, mL/100 kg 165 165 165
Slump, mm 127 115 140 127 127 115 115
Air, % 1.1 0.8 0.9 1.3 0.9 0.8 0.8
Pump Pressure, MPa 7.6 8.6 7.6 9.0 7.6 19.3 7.9

 

Example 2 – Portland Cement/Fly Ash Concrete (English Units)

Manufactured Sand Content 0% 40% 40% 60% 60% 80%* 80%*
Cement, lb/yd3 417 418 425 427 410 415 411
Fly Ash, lb/yd3 110 110 111 111 108 111 108
Stone, lb/yd3 1630 1632 1636 1583 1562 1547 1555
Total Sand, lb/yd3 1496 1515 1483 1560 1562 1570 1577
Total Mix Water, lb/yd3 300 305 303 298 306 304 313
WR Admixture, oz/cwt 4 4 4 4 4 4 4
V-MAR 3, oz/cwt 2.5 2.5 2.5
Slump, in. 5.0 4.5 5.5 5.0 5.0 4.5 4.5
Air, % 1.1 0.8 0.9 1.3 0.9 0.8 0.8
Pump Pressure, MPa 1100 1250 1100 1300 1100 2800 1150

* In the extreme case of using 80% manufactured sand in these lean mixes, the untreated concrete segregated during the pumping process, and pump pressures rose to
unsustainable levels. However, even though the use of V-MAR 3 reduced the pump pressure to “normal” levels, and the concrete was placeable, it remained more difficult to place than the control mix.

Conclusion

The use of V-MAR® 3 in pumped concretes incorporating different levels of manufactured sand reduced the resultant pumping pressures back to the same level as the control concrete, which did not contain manufactured sand.

Since V-MAR® 3 is treating the free water in the mix and not the cement (as most admixtures do), dosage rates were originally quoted based on the free water in the concrete. Although accurate, this nomenclature has proved confusing to those used to the more familiar dosage units for admixtures. Thus, typical V-MAR® 3 dosages required for pumping applications are found in the range of 1.95 - 3.90 mL/L (¼ - ½ fl oz/gal) of water in the concrete, or 96 - 160 mL/100 kg (1½ - 2½ fl oz/100 lbs) of cementitious materials.

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Last Updated: 2018-12-28

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