CREATING TOMORROW S SOLUTIONS IT S THE MIX THAT MATTERS IN TUNNEL CONSTRUCTION

Transcription

1 CREATING TOMORROW S SOLUTIONS Construction I Infrastructure I Tunneling IT S THE MIX THAT MATTERS MODIFIED Sprayed concrete IN TUNNEL CONSTRUCTION

2 ETONIS ADVANCED TECHNOLOGY FOR TUNNEL CONSTRUCTION ETONIS is an innovative sprayed concrete modifier that lends your concrete special qualities and allows you to master even the most difficult situations, such as applications on wet rock faces, problematic geological features or extreme site conditions. WACKER has developed ETONIS 150 and ETONIS 850 specifically for tunnel construction applications. Less Rebound Means Lower Costs Sprayed concrete enhanced with ETONIS is hallmarked by its excellent adhesion. This significantly reduces rebound ETONIS can cut rebound by more than half, depending on the relative amount of polymer, the concrete formulation and the spray technique used. Figures like these will make cost-conscious project managers sit up and take notice less rebound means lower material costs and reduced overheads for transporting material from the mixer to the construction site and/or waste from the tunnel to the landfill. Less rebound also results in improved spraying performance, easier handling even under extremely difficult conditions, and, finally, shorter time on site. And in the long term, modifying concrete with ETONIS also prevents damage to the structure. This is partly the result of the favorable compaction properties of polymer-modified sprayed concrete. For example, a polymer-modified tunnel lining can withstand hydrostatic pressure and aggressive media for long periods of time. The modified concrete is also resistant to sulfates, chloride and CO 2, which helps prevent damage in the long term. ETONIS and SILRES BS are registered trademarks of Wacker Chemie AG. 2

3 WACKER ETONIS Outstanding adhesion Excellent compaction properties Reduces rebound Protects against hydrostatic pressure Prevents cracks Resistant to chloride, sulfates and CO 2 Less waste material Less material used Fewer transport runs Less machine downtime Improved spraying performance Longer renovation cycles Reduced construction time Lower overall costs 3

4 MODIFIED Sprayed concrete A PROMISING SOLUTION FOR TUNNEL CONSTRUCTION WACKER has been testing polymermodified sprayed concrete mixtures under real-life conditions since The following project descriptions illustrate how tunnel construction companies and their clients can profit from the use of modified sprayed concrete. The Hagerbach Test Gallery: A Test Series Performed with Various Formulations and Different Polymer Contents WACKER tests its ETONIS modifier under real-life conditions at the Hagerbach Test Gallery in Flums, Switzerland. For the first series of tests performed in 2008, WACKER application technology experts initially looked at ETONIS - modified wet-sprayed concrete to assess rebound and determine its compressive strength. The mixtures tested contained polymers in concentrations ranging between 1.7% and 10% relative to the amount of cement. Tests of various formulations showed that roughly 2% of ETONIS modifier already helps to achieve a long-term, reproducible reduction in rebound for concrete applied using the wet-spray method. The optimum level of ETONIS was found to be 7.5%, which reduced rebound by up to 71% over the unmodified control system. These positive results led to the use of enhanced sprayed concrete when a new cavern was built in Stetten Salt Mine: Construction and Lining of the Clara Tunnel The subterranean world of the Stetten Salt Mine covers over ten square kilometers. Because a new access tunnel was needed for logistical reasons, the Clara tunnel was opened in August 2008 to connect the salt mine to the surface. For securing and expanding the freshly blasted tunnel, WACKER applied ETONIS - enhanced wet-sprayed concrete in areas susceptible to water encroachment. The application in Stetten clearly confirmed what WACKER engineers knew from other tests: modifying the concrete with 10% ETONIS significantly reduced rebound. Plus, the rheological properties and slightly sticky consistency of the modified fresh concrete gave it outstanding processing characteristics. And that s not all: even applying the concrete to a wet rock face proved to be no problem. Because it optimizes cracking behavior, ETONIS -modified sprayed concrete has since been used to seal a section of the tunnel lining to protect it from hydrostatic pressure. The 2011 inspection confirmed that the results were impressive compared to the unmodified system. The Hagerbach Test Gallery: A test series conducted on a variety of formulations 4

5 The Hintermuhr Pumped Storage Power Plant: Renovating the Pressure Tunnel The Hintermuhr pumped storage power plant in the Salzburg state of Austria is an unusual type of power plant, with all of its systems housed underground for reasons of nature conservation. The primary function of the Hintermuhr power plant is to serve as a buffer. In times when consumption is low, water is pumped to Rotgüldensee, a lake lying at a higher elevation, so that it will be available for generating electricity when demand is high. In 2009, the pressure tunnel used for this purpose began registering water loss, and grouting did not produce the desired effect. This meant it was time for another renovation, and, due to the confined conditions in the tunnel, drysprayed concrete was the only feasible option. Because the seal needed to be watertight and the construction site presented an extremely difficult logistical situation, the decision was made to modify the concrete with 7.5% ETONIS. The result? Despite a tunnel diameter of only 4 meters, rebound was reduced by nearly 40%, saving roughly 156 tons of concrete along a 70-meter stretch. That, in turn, cut the construction time, allowing crews to complete renovations before the spring melt despite the fact that avalanches had reduced the already short time frame still more. Other advantages included the money saved due to reduced transportation and waste disposal costs. On the whole, renovation of the Hintermuhr pressure tunnel clearly shows that the financial benefits of polymer-modified sprayed concrete quickly compensate for the higher material costs. Renovation was successful from a technical perspective as well: the pressure tunnel has now been in operation for over two years with no significant water loss. The Mont Terri Rock Laboratory: Rebound Tests with ETONIS 150 and ETONIS 850 The Mont Terri Rock Laboratory in the Jura canton of Switzerland serves the international research community as a resource for performing geochemical, geotechnical and hydrogeological experiments. In the spring of 2011, WACKER conducted a variety of tests on the rebound behavior of polymer-modified dry-sprayed concrete. The results have shown that adding ETONIS 150 can reduce rebound by between 7% and 28%. ETONIS 850 reproducibly reduced rebound by between 25% and 33%. 5

6 WORKING TOGETHER FOR OPTIMUM RESULTS WACKER s Experts: Always at Your Side WACKER application technology experts work with our clients on every tunnel project, from initial project discussions to technical support at the construction site. The latter is an indispensable part of any sprayed concrete project, since you can only achieve your desired results if the mixture of modifier, cement, aggregates, classic additives and water is just right. Our on-site engineering team uses drill cores from preliminary tests to determine strength development before a given mixture can be used in a final formulation. Additional tests are conducted to evaluate the fresh concrete characteristics. Economic considerations also play a major role in establishing the ideal mixture. The use of polymer-modified sprayed concrete should ultimately pay off for all partners. A Wide Array of Specialty Building Protection Products WACKER is the only major chemical company that produces both silicone and polymer products. Thanks to this unique combination, we can offer you a comprehensive line of building protection products. WACKER materials experts have developed silicone-based, water-repellent building protection products for tunnels and bridges. These products, sold under the name SILRES BS, prevent water and salts from permeating concrete. One recent use of these products has been to apply a hydrophobic coating to the Gotthard Tunnel in Switzerland. In just a single night, the tunnel entrances and exits were impregnated with SILRES BS to protect them from road salt. Please contact us at the following address if you would like more information about SILRES BS: construction@wacker.com Become an ETONIS Project Partner WACKER specialists have been developing ETONIS for six years and are now migrating from first reference projects to large-scale tunneling applications, where polymeric modifiers are still a novelty. To accomplish this, we are looking for project partners who would like to use ETONIS in tunnel construction with the aim of gathering additional experience under real-life conditions. Interested? Then become an ETONIS project partner. Mr. Frank Gregory will be pleased to receive your call or frank.gregory@wacker.com, Tel. +49 (0)

7 ExpErtisE and service network on FivE continents sales and production sites, plus 20 technical centers, ensure you a local presence worldwide. WACKER is one of the world s leading and most research-intensive chemical companies, with total sales of 4.91 billion. Products range from silicones, binders and polymer additives for diverse industrial sectors to bio-engineered pharmaceutical actives and hyperpure silicon for semiconductor and solar applications. As a technology leader focusing on sustainability, WACKER promotes products and ideas that offer a high value-added potential to ensure that current and future generations enjoy a better quality of life based on energy efficiency and protection of the climate and environment. Spanning the globe with five business divisions, operating 25 production sites, WACKER is currently active in over 100 countries. The Group maintains subsidiaries and sales offices in 29 countries across Europe, the Americas and Asia including a solidly established presence in China. With a workforce of 17,200, WACKER sees itself as a reliable innovation partner that develops trailblazing solutions for, and in collaboration with, its customers. WACKER also helps them boost their own success. Our technical centers employ local specialists who assist customers worldwide in the development of products tailored to regional demands, supporting them during every stage of their complex production processes, if required. WACKER e-solutions are online services provided via our customer portal and as integrated process solutions. Our customers and business partners thus benefit from comprehensive information and reliable service to enable projects and orders to be handled fast, reliably and highly efficiently. Visit us anywhere, anytime around the world at: all figures are based on fiscal 2011.

8 Wacker Chemie AG Johannes-Hess-Strasse Burghausen, Germany Tel Infoline e/05.12 reprint 6810e/11.11 The data presented in this brochure are in accordance with the present state of our knowledge but do not absolve the user from carefully checking all supplies immediately on receipt. We reserve the right to alter product constants within the scope of technical progress or new developments. The recommendations made in this brochure should be checked by preliminary trials because of conditions during processing over which we have no control, especially where other companies raw materials are also being used. The information provided by us does not absolve the user from the obligation of investigating the possibility of infringement of third parties rights and, if necessary, clarifying the position. Recommendations for use do not constitute a warranty, either express or implied, of the fitness or suitability of the product for a particular purpose.