Essay \"Site Report - Boral Concrete\" PDF

Preview

Summary

Site Report - Boral Concrete
...

Description

UOW

Site Report Boral Concrete 2010

0|Page

Abstract The purpose of this report is to provide a summary of the concrete produced at Boral, how concrete production is both sustainable and as efficient as possible and the production process. Boral produces concrete which has a large variety of purposes ranging from concrete slabs to structures creating minimal waste in the process due to recycling.

1|Page

Table of Contents Abstract.............................................................................................................................................1 Introduction.......................................................................................................................................3 Plant Information...............................................................................................................................3 Materials Used...................................................................................................................................3 Trucks.................................................................................................................................................4 Recycling............................................................................................................................................5 Sustainability.....................................................................................................................................5 OH&S Issues.......................................................................................................................................5 Conclusion.........................................................................................................................................5 References.........................................................................................................................................6

2|Page

Introduction Concrete is one of the most commonly used building materials used today for a variety of purposes as it is one of the most easily made and is extremely versatile. Boral is a manufacturer of concrete and is a fairly large company, having around 220 different concrete manufacturing plants around Australia, which supplies concrete used in both highway and residential purposes.

Plant Information The Boral concrete production plant is based off conveyor belts. Aggregates are placed above a conveyor belt, which when needed, would be placed onto the belt and then moved to another conveyor belt. Boral tests the concrete it produces every couple of months to ensure that the product that they guarantee is up to the standard which is expected from such a large company.

The second belt was sent to the top of a tower where the aggregates were placed into a concrete truck after having water, cement and other assorted admixtures added to it, where after the cement truck started rotating would produce concrete. The placement of the materials into the cement truck produces a lot of dust, so a fresh water spray is used to suppress the dust produced. The Dunmore site typically produces 20 loads of 6m3 of concrete per day, however on some days they receive large orders of over 600 loads. When such orders occur the three trucks Dunmore Boral has cannot cope and asks for assistance from other cement producers nearby for their trucks and drivers. On site there are typically three drivers and one plant operator at a time, to deliver and make the concrete.

Materials Used Some of the materials which are used in the concrete production process include blue metal, both 20 and 10mm, dune sand, river sand and C27 sand, fly ash. A noticeable Supplementary Cementitious Material (SCM) which is missing is slag. The reason why slag is missing is blue metal at the Dunmore quarry is available in vast quantities and, in general, produces better quality cement at a cheaper price as Boral would not need to pay for transportation costs from Blue Scope Steelworks.

3|Page

The moisture reading in the aggregates is taken three times a day to make sure the water cement ratio is at the required level, so the machinery adjusts the amount of water to put into the cement mixer. The other components of the cement mixture include water, cement and admixtures. The Dunmore Boral concrete production plant chooses to use Shrinkage Limited cement (SL) as its General Purpose cement (GP) as it is more economical since they provide a lot of concrete for the road works around Wollongong. Boral typically uses about 500L of admixtures per month, usually water reducing admixtures. Some of the admixtures which the company uses are POS80 (water reducer), MA940 (air entrainer) and POS999 (accelerator) amongst others. A typical load produced by Boral has approximately 9000kgs of aggregate, 1400kgs of cement and 820L of water. This produces a concrete with a water cement ratio of approximately 0.468 with about five cubic metres of cement.

Trucks The cement trucks Boral located in Dunmore uses are around six cubic metres, and the plant has 3 trucks, however if Boral gets a large order they can generally ask a neighbouring cement plant to borrow several trucks and the drivers needed. These trucks are used to both mix and supply cement to various locations within a 90 minute radius of driving, if the location is too far away the cement starts to set and the properties of the concrete begin to change from its elastic to hardened state. The trucks are able to stop the cement from setting for 90 minutes through agitation of the material as it is constantly moving, which helps slow the chemical reactions. The trucks when being loaded typically sit underneath the tower and are filled with the concrete components and then are mixed at a speed of 14-18RPM, and when being drove to the destination, agitated at 2-6RPM to prevent setting.

4|Page

Recycling Every possible effort has been taken with the Dunmore Boral site to help reduce the amount of waste which is produced, so much in fact, that there is no waste at all. Any left over concrete is turned into concrete blocks which are sold to companies for various purposes, the concrete which is left inside the mixer after being emptied is washed out using recycled water and then left in a pile. When the pile of dried concrete is large enough it is transported to a quarry in Nowra for reuse. The recycled water is obtained on site by using drainage system and water storage tanks which is then used for a variety of purposes.

Sustainability The sustainability at the Dunmore Boral concrete site is as perfect as a cement site can be as the site produces no waste. Everything is reused, or comes from somewhere that has been used before besides the aggregates, however fly ash is used which is also a recycled product. The rainwater is recycled, saving on the use of clean water which would otherwise be used for consumptions by humans. Recycled aggregates are also being used by Boral for low to medium strength concrete. All efforts have been made with Boral to ensure as much of the ingredients for making concrete are recycled.

OH&S Issues There are several OH&S issues on site and measures are taken to prevent accidents happening. Most of the issues come from aggregates possibly falling off the conveyor belt on the way to the top of the tower, to prevent this possibly damaging a human hard hats and eye protection is worn. Eye protection is also used for the loading of aggregates into the cement truck as there is a large amount of dust produced. Steel capped boots and are worn to help protect feet from behind crushed by the aggregate moving tractor. High visibility vests are worn so the operator driving the tractor are more visible, helping prevent possible injury. Earmuffs are also worn, however only during certain processes, generally when loud machinery is being operated such as the loading process of the concrete mixer.

Conclusion The Dunmore Boral concrete site is reasonably small but produces a lot of concrete which is very sustainable. Boral produces a lot of concrete for a wide variety of uses, from highways, to suburban houses, to prestressed concrete slabs. The tests performed ensure that the concrete which is delivered to various places is equivalent to what they claim; guarantying that the cement will not fail or wear too quickly for the purpose it was prescribed for.

5|Page

References Nawy, E.G. 2008, Concrete Construction Engineering Handbook, 2nd edition, CRC Press, NW, USA Lume, E 2010, Lecture 3 Concrete Slides 2010, NSW, Australia Lume, E 2010, Lecture 2 Concrete Slides 2010, NSW, Australia Boral Ltd 2009, Boral: Boral Limited Annual Review 2009, NSW, Australia King, S 1996, From the ground up – Boral’s first 50 year, State Library of NSW Press, NSW Australia Wilby, C. B. 1977, Concrete for Structural Engineers, Newnes-Buttersworth, WC2B UK Sustainable Concrete, 6/10/2010, http://sustainableconcrete.org.uk

6|Page...