Shotcrete results show encouraging signs for mining

“There is no doubt, this product has great potential for use in the mining industry in particular,” VCA marketing and development manager Ian Hampton said.
“In just over three hours CTS Rapid Set Shotcrete achieved a compressive strength of 33.5MPa. In 24 hours a compressive strength of 50MPa and 52MPa after 65 hours - very impressive.
“This concrete technology presents miners the opportunity to begin working in areas that require shotcreting several hours earlier than when conventional products are utilised.”
VCA conducted the tests at its Marsden Park facility in Western Sydney on May 11th.
Various mixes were trialled with astounding results achieved with CTS Rapid Set Cement when compared with conventional Portland Cement-based shotcrete.
“VCA is in the early stages of researching this new technology and the results are driving us to take the trials to the next level,” Hampton said.
“We see a huge potential for the use of CTS Rapid Set Shotcrete in the mining sector in particular which will filter through to civil construction.”
“Our trial partners Antec Engineering, who supplied the Reed pump and the shotcreter, and KPS Civil Contractors were very impressed with the technology and they too predict there will be strong demand for CTS Rapid Set Shotcrete into the future.”
Hampton said VCA and KPS will embark on a further series of trials and the results will be available on the VCA website (www.volumetric.com.au) as they come to hand.
Volumetric Concrete Australia, incorporated to introduce and sell unique concrete technology into the civil, construction and mining industries, believes its expertise will revolutionise the way concrete is produced and applied in Australia.
Hampton said the complementary product range - International Mobile Mixers (IM Mixers), CTS Rapid Set Cement, Minnich drills and vibrators and specialised concrete hand tools - gives contractors a niche and edge to finish projects in record time.
VCA has spent the last three years developing and in some cases enhancing these products for the Australian market, to make sure that they meet all criteria to produce and place concrete, and to give contractors the edge on time sensitive and remote projects.
International Mobile mixers (volumetric mobile concrete units on trucks nicknamed “square Aggies”) can be used as:
• Mobile concrete batch plants and stationary batch plants which can produce any mix design using Portland cement at up to 50m³/hour;
• Mobile pug mills using any stablement and as blending plants for any type of material up to 90t/hour;
• Mobile CTS Rapid Set cement concrete batching plants that can produce up to 50m³/hour; and
• Remote area concrete production units, as the plants can travel for days before batching the raw materials on the truck into concrete.
“The mobile volumetric units, are used in all types of civil, construction and mining applications, to produce all types of concrete from shotcrete to slab mixes,” Hampton said.
They can produce up to 50m³ an hour when stationary and loaded continuously. They also carry different payloads - there are 2m³, 4.5m³, 6.5m³ and 10m³ models - to produce from as little as half a wheel barrow load at a time, to about 1m³ a minute. They also have on-board computers and printers that can produce dockets to substantiate the amount of concrete produced.
IM Mixers - in wide use across the Northern Hemisphere - minimise concrete waste by being able to produce on demand, the precise amount of concrete needed. The norm for engineers and estimators is to allow between 10 and 15 per cent waste on a project, but IM Mixers reduce this figure to as little as 2 per cent.
CTS Rapid Set concrete, a hydraulic cement that can achieve strengths of up to 30MPa in one hour and 55MPa in three hours, allows contractors to reduce costs by as much as 50 per cent.
Conventional Portland concrete based products take as much as a week to attain similar strength. This naturally reduces time expended on projects and associated costs such as traffic control, finishing time and backfilling retaining walls.
“One of the main questions asked of VCA by engineers is, ‘If the concrete achieves high early strength in 1 hour, what sort of temperature does the concrete reach and does this affect shrinkage,” Hampton said.
“We say that concrete temperatures are higher than Portland cement mixes produce, due to rapid hydration of the CTS concrete. We have experience of them reaching up 30 degrees Celsius on the outer skin.
“But shrinkage is as much as two thirds lower than standard Portland cement mixes. Tests to date have shrinkage ranging from 140µm up to a maximum of 250µm, well below the average of 500 to 700µm that Portland concretes produce.”
Minnich Drills and vibrators have been specifically imported into Australia by VCA for concrete drilling and compaction. The drills are air operated and can drill horizontally and vertically. The drills come in single and multi head configurations and can bore a 41mm diameter dowel hole 250mm deep in 20 seconds.
“In a recent project VCA needed 41mm diameter dowel pin holes drilled in 40 locations in one hour. Using conventional core drilling methods, this would have taken from seven to 10 minutes for each hole, requiring a total of three to four hours. But by using the Minnich A1C48 unit, VCA completed the task in about 40 minutes,” Hampton said.

Further information tel: +61 (0)423 880 993; +61 (0)2 9622 9622; or +61 (0)2 9721 3914.