The RIX Group - Specialist ContractingEstablished in 2000 specialising in shotcreting, specialist contracting and civil construction.As our business and capabilities expand so does our service and quality. With a high level of in house expertise, willing clients, suppliers and a passionate embrace of new challenges, we have successfully created new divisions to better serve our clients needs. Our following divisions work closely together to provide our clients with complete nationwide specialist contracting solutions.
Click the tabs to left for more information or read below for a better understanding of some of the solutions we provide:
1. SHOTCRETE APPLICATION - simulated rock; contiguous piles; panels; batters; construction; rail cuttings; road corridors etc.
2. CIVIL & MINE CONSTRUCTION - tunnel, shaft, portal & box cut lining & support; welding; concreting; formwork; fabrication etc. The RIX Group are expanding rapidly & now specialise in Civil Tunnel Contracts, Rail Construction Contracts, Specialised Drilling, Rockbolts, Rockfall Netting, Soil Nails & Shaft Lining.
RIX also have Underground Robotic Shotcrete Equipment and a Remote Shotcrete Shaft Liner for ground suppor
RIX have in-house Engineers with the experience to help you with your more challenging projects. The RIX team are regularly travelling to all parts of Australia to provide our clients with shotcrete solutions. If you have a project requiring Civil or Rail Construction, Shotcrete, Rockbolts, Soil Nails, Drilling, Underground Robotic Shotcrete Application, Rockfall Netting or other forms of geotechnical stabilization you have found the right website. As you read on, you will see some of our more challenging civil & rail construction projects. N.B. You can read the photo caption by scrolling your mouse over the photos. In the USA where the process was invented, Shotcrete is commonly called Gunite. Since its inception in the early 1900's shotcrete application has advanced.
Technically the definition of Shotcrete is " the spraying of concrete via air or hydraulic pressure". This can be achieved by two methods. 1. using mechanics & hydraulics to force wet concrete through a hose, where compressed air then increases the Shotcrete's velocity at the discharge end
or
2. using compressed air to blow a dry mix (gunite) through a hose, where water is then added at the discharge end.
In Eastern Australia method one is commonly called Shotcrete & method two is commonly called Dryshot.
Both Shotcrete & Dryshot use compressed air to increase discharge velocity. This increases the ability of the shotcrete to adhere to surfaces that normal concrete would not adhere to. For example tunnel roofs, rock faces, steep batters & most free form surfaces. Shotcrete is used extensively in civil construction, tunneling, shotcrete pools & geotechnical stabilisation around roads, railways & other forms of excavation.  .gif) Both Shotcrete & Dryshot differ from normal concrete in the size of the aggregate. Normal concrete generally has an aggregate size of 20mm where as Shotcrete generally has an aggregate size of 10mm & dry shot has an aggregate size less than 10mm.
Shotcrete is best used in situations that require: · quantifiable water/mix design
· large quantities & fast application
· consistent admixture/concrete ratios
· minimal rebound, or aggregate loss
· Steel fibres or Structural Synthetic Fibres such as Barchip
  Dryshot is best used in applications that require:
· smaller quantities (<20m³)
· application via Rope Access
· rock simulation (mock rock)
· longer pumping distances, limited access or remote areas
  SHOTCRETE APPLICATIONS
1) Civil Construction - Shotcrete & Dryshot can be shaped, contoured, leveled, coloured, moulded, imprinted, smoothed & reinforced. Common terms for the myriad of Shotcrete finishes include:
· gun finish
· wood, float, sponge
· steel trowel
· oxide (colour)
· simulated or mock rock
Shotcrete has been used to construct multistorey hotels, wheat or concrete silos, hydroelectric tunnels, underground sewers, bridge abutments, artificial white-waterways (Penrith Whitewater Stadium - Sydney Olympics), dam slipways, car parks, skateboard ramps, nuclear missile shafts, water reservoirs, & retaining walls.
  2) Tunneling - Shotcreting is extensively employed in mines & tunnels due to its ease of application & ability to adhere to surface that normal concrete would not. With the addition of silica fume shotcrete has great characteristics for use in mines.
Shotcrete’s popularity in tunneling & mining increased upon the introduction of fibre reinforced shotcrete. This new technology extensively replaced steel meshing which was difficult & slow to install in the underground environment. Of these additives structural Synthetic Fibre (such as Barchip) has emerged as a popular choice in recent years. Steel fibre leaves a sharp surface that can easily tear the skin were as the polymer alternative has no OH&S issue, while achieving comparable tensile strengths.   3) Culvert Construction & Maintenance - Culverts are under the spotlight at the moment due recent failures that have resulted in numerous fatalities. Culverts that have been constructed from galvanised iron are reaching the end of their service life, rusting out & failing.
Shotcreting & reinforcement have been selected in many cases to increase the strength of the failing culvert while minimising the restriction to flow volumes. 4) Geotechnical Stabilisation- Shotcrete is used extensively with rock bolts, soil nails, temporary anchors, Maccaferri rockfall mesh, reinforced steel & steel fibres to reinforce loose ground conditions, hazardous geology & rock fall.
5) Landscaping - Shotcreting is used in the creation of decorative landscapes. Due to shotcrete’s ability to be coloured, shaped, contoured & carved the possibilities & creations are endless. Mock or artificial rock like that used recently in the Great Southern Oceans Precinct in Taronga Zoo, can be incorporated around pools to resemble natural features like rock ledges or waterfalls.
6) Shotcrete Pool Construction - Shotcrete Pools can be completed in a single day & have no construction joins. This minimises the potential for leaks & cracks.
As opposed to formwork, shotcrete pools mix design can be greater controlled due to the reduced application time. Cutters & Finishers have honed their skills over years of shaping shotcrete. Shotcrete can be worked to produce sharp, straight & parallel edges equal to that of a formed structure, but without the construction joins & in a fraction of the time. The possibilities for shotcrete are endless in the hands of a craftsman, pools can be shaped to suit the site & the client's individual design. Subtle additions to your pool are not a problem with shotcrete construction as opposed to mass produced pools. Shotcreting enables seamless construction & sleek design.   DON'T KNOW WHERE TO START??? - TYPICAL STEPS IN GEOTECHNICAL STABILISATION
Following are some of the steps in a typical ground stabilsation. We hope this will help you in finding a solution for your poor ground conditions.
1. Site Assessment
The site will need to be assessed by a Geotechnical Engineer who will identify areas of geological instability. Taking the geotechnical assessment, an Engineer with expertise in structural strength will then formulate a design for retaining the ground in question. The Engineer's design will then be implemented as the solution.
This design may incorporate:
- Maccaferri Rockfall Mesh or Netting
- Rockbolts or Ground Anchors
- Soil Nails (rockbolts for soil)
- Shotcrete or Fibrecrete
2. Contractor Selection
The Site Owner or Primary Contractor will then Tender out the job.
It is in the Site owner's best interest that the wining tender addresses all the safety, quality & environmental requirements as laid out by the tender package. A Site Owner or Primary Contractor will normally ensure that the winning Contractor has:
· a proven track record
· quantifiable OH&S culture
· environmental awareness
· quality assurance & control
· sound plant
· an adequate corporate skill base
Once the contract has been awarded to the Contractor, preparations for mobilising on site begin.
3. Site Safety Assess the site & task for potential hazards. Implement controls that will minimise the potential for these hazards to harm.
Design a work methodology for the task that isolates these hazards or minimises them to a level of acceptable risk. Ensure that all employees & the surrounding public are aware of the hazards & are isolated from harm. 4. Site Establishment
Gain access to the geologically defective area. This may need to be done through:
· Industrial Rope Access
  · Elevated Work Platforms
  · Manitou or Crane
  · Helicopter
  5. Site Preparation
De-vegetate the site to be treated. This may need to be done by trained Arborist’s who have proven competency in chainsaw use. Often if the geologically defective area is at height this is achieved best by Arborist’s with Industrial Rope Access competency.
Next it is important to remove all loose rock & soil to give the shotcrete a strong key to the geologically defective area. This is called "scaling the site" & once again if the geologically defective area is at height this is achieved fastest & cheapest via a team of Industrial Rope Access technicians.   6. Mesh Installation
Once the area is scaled & deveged the geologically defective area is ready for treatment.
The Engineer may recommend that:
- areas be shotcreted - to stabilise & prevent further weathering
- Maccaferri Rockfall Netting be installed - to contain any future rockfalls
- installation of rockbolts - to hold rocks in position
7. Rock Bolt & or Soil Nails Installation
Rockbolts come in all shapes and sizes. Rockbolts can be either fibreglass or steel. They can be simple bar (passive) or mechanical shell bolts (tension). What ever the design or make up of rockbolts generally they will need to be grouted to achieve both corrosion protection & stability in the site's geology.
Rockbolting is traditionally used in situations where loose boulders and or wedges of rock are fracturing away from cliff faces and or steep rocky slopes. We recommend visiting the DSI Australia site www.rockbolt.com for a more comprehensive range of rockbolts.   8. Drilling of holes for Rock Bolts
Holes will need to be drilled. The Engineer will specify both depth & diameter.
Drilling can be achieved with various plant: · Excavator with either rotary or percussion drill
· Hand Rockdrill (rotary or percussion) e.g. SIG or Boar rock drills
· Rambor Roof Bolters, Eagle Rib Drill
These Rock Drills can be pneumatic drills or hydraulic drills. Excavator drilling will deliver the largest diameter hole but may be hampered by height or access restrictions. Hand rock drills will deliver the smallest hole but are light enough to be carried into remote sites. If needed Hand Rockdrilling can be used by Rope Access Technicians at height in difficult access situations.
If the drilling contractor is large enough then rock drills of all sizes & shapes will be owned to deliver the desired diameter hole in the desired location.   9. Grouting of the Rockbolts
Once drilled the holes are then cleaned. If the rock bolt is steel these holes will need to be large enough to house both the rock bolt & a grout for corrosion protection. This corrosion protection may be a cement or an epoxy grout.
Plunge grouting is the most common method for grout insertion into the hole. This enables grout volumes to be monitored thereby ascertaining any grout leakage into subsurface voids. Once the hole has been filled with grout, the rockbolt is installed. The grout will need to be left to cure. This is so the grout achieves maximum strength before the plates are put on & the nuts are tensioned securing the mesh. 10. Anchoring of Mesh
In the case that Maccaferri rockfall netting is used, wire cables are integrated into the rock mesh. These cables can be located under the rock bolt plates or attached to rock bolts with chains for maximum strength. Ensure the rock bolts & the mesh are now secure.
11. Shotcrete Pump Selection
Shotcrete pumps come in all shapes & sizes. If a large Shotcrete Contractor has been selected (such as RIX who presently own 16 pumps both trailer & truck mounted) they will own a good range to suit the majority of sites.
If the pumping distance is large between the geologically defective area & the closest vehicle access point relay trailer pumps, cranes or Dryshot can be used.   12. Shotcrete Application
Shotcrete is delivered to site via agitator trucks. The mix is normally sampled & tested in a laboratory for compressive strength.
An experienced nozzle man can manipulate the shotcrete to most surfaces & gradients without too much waste or over-break. It is important that all voids are filled with no air-pockets. Normally the shotcrete is sprayed from left to right & from bottom to top. 13. Shotcrete Finish
This is the business end for most project managers as this is what the client & public will see.
In the finishing of shotcrete there are many possibilities. Shotcrete can be: - Unfinished (Gun Finish)
  - Unfinished (Gun Finish) with an Oxide
.jpg)  - Cut, wood floated & steel troweled for a sleek finish. This is often used in areas where the shotcrete wall will later be treated to repel water in sub-surface or sub-sea level sites.
- Shotcrete can be carved & coloured to simulate to rock features or sandstone block work. Examples of this can be seen in Taronga Zoo’s new attraction Great Southern Oceans Precinct. This mock rock can then be further softened with plants to reduce any visual impact.
  Curing compound can be applied to the shotcrete surface. This curing compound reduces the potential for surface cracking.
If the shotcrete contractor has been chosen carefully, a Quality Control procedure was rigorously followed during the project & the product will enjoy design life defect free.
In recent years Shotcrete has been used in many road & rail projects, where vertical excavations are required to gain maximum space to boundaries. Shotcrete's purpose in these situations have been paramount for shoring. Often the shotcrete is ultimately covered by precast panels as a final finish.
The RIX Group are able to offer Project Managers shotcrete as a final finish. The finished shotcrete resembles a rendered wall or a smooth trowel finish. This greatly reduces construction times & enhances our client's programs & budgets.
SILICA FUME
Silica fume is an ultra-fine powder 100 times smaller than a grain of cement. When introduced into shotcrete these fine particles assist to fill any voids. Silica fume significantly enhances the overall compressive strength of the shotcrete mix.
Characteristics of Silica Fume in Shotcrete
· enhanced compressive strength
· reduced permeability
· improved corrosion resistance
· improved shotcrete pump ability
· improved cohesion resistance to segregation
· improved adhesion to tunnels, culverts, steep geology
· improved abrasion resistance
· improved resistance to most sulphate and various other forms of chemical attack
SAFETY FOR SHOTCRETE CONTRACTORS
Safety has high priority in New South Wales & Queensland. Government Authorities in these states regulate, inspect & monitor workplaces in attempt to increase safety awareness & safer work practices. Shotcrete contractors are required by law to protect their employees from work injury.
RIX are required to keep their: · shotcrete plant maintained & safe
· construction processes & work methods safe
· chemicals & hazardous substances stored & used as per the manufacturer's recommendations
RIX take their responsibility to provide a safe workplace seriously. Our Occupational Health, Safety and Rehabilitation Policy is based on a belief that the well-being of people employed at work, or people affected by our work, is a major priority and must be considered during all work performed on our behalf.
People are our most important asset and their health and safety is our greatest responsibility as shotcrete & geotechnical contractors. The public shall be given equal priority to that of our employees.
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