We are in an area that in the past used natural sand for all concrete mixes. We all know the times have changed. My question is, how do we educate the pump owners and operators in our area that manufactured sand is the future?
They claim that it will not pump, and it wears the unit out much faster than natural sand. We also have discovered they are priming the pump with the concrete mix.
I would like to hear from other concrete suppliers and pump manufactures on the pumping of manufactured sand. Is it a wide spread problem?
It's only a matter of time before the pumping guys will have 2 choices -Pay a premium for concrete made with natural sand or ;Pay for add mixtures and the additional wear costs
Pumping concrete with manufactured sand increases the pumping pressure and causes additional wear/tear on equipment. But t the more organic issue is the ability to accept the change.
To manufactured sand mix designs pump, place, and finish just fine. The challenge is in proper proportioning (just like any concrete mix design) and the ability of the finisher to accept those changes.
While it is true that rounded particles should pump well than angular particles do, many natural sands available to our region have very little on the 0.15mm, and 0.3mm.
The manufactured sands we use provide the missing fines that not only assist pumping but also finishing. Where possible, we blend both sands for the best of both worlds.
We are also fortunate to have a department of transport that recognizes a finer grading that benefits all parties. The department of transport passing spec is 15-20% for the 0.3 mm and 8-22% for the 0.15 mm.
Degussa Admixtures has actually created a Liquid Sand Program that has helped producers and contractors throughout the nation to overcome the problems associated with the use of manufactured sand in concrete.
This Liquid Sand Program involves the use of a unique VMA (Viscosity Modifying Admixture) that lubricates the concrete mix to make it easier to pump, place, and finish.
This means reduced pump pressures, less wear and tear on equipment, and less work to finish the surface. The VMA also helps to control excess bleeding, which can be an issue with the use of manufactured sand.
YulebaMinerals (www.yulebaminerals.com.au ) produces a natural sand with full grading which is available throughout Roma, Miles, Chinchilla and the Southern Queensland.