The only magazine dedicated to the , falsework, and scaffolding industries worldwide No 2

• Separate Placing Booms Flying at Denver Airport • Tartu Bridge Is Big Challenge • Warsaw Spire, Warsaw, Poland • New flood retention reservoir essential • Insulating Concrete Formwork • Switzerland’s largest private construction site • Tallest Residential Building in Western Hemisphere Published by VVV Limited Publisher / Editor Editorial Comment Roger Lindley Email: [email protected] Tel: +44 1279 600598 Formwork & Administration Colleen Lindley Falsework Tel: +44 1279 600598 Supplement Group Advertising Director Darren Dunay Email: [email protected] Tel: +1 201 781 6133 USA Holly Hicks [email protected] From 2015, Contractors World will publish a quar- +1 412 660 5360 terly supplement devoted to formwork, falsework, OH, PA, MD, WV, VA, NC, SC, GA, FL scaffolding and concrete placement. Don Sherbo As structures get more complex and reach unim- Rummel Media Connections [email protected] aginable heights, so they introduce different challenges + 1 608 215 8852 to contractors. MN, IA, MO, AR, LA, WI, IL, IN, MI, KY, TN, MS & AL Often these stretch engineering to the maximum as seen with the 432 Park Avenue tower in New Germany, Austria & Switzerland Email: [email protected] York. Without the aid of chemists and physicists who Tel: + 49 2131 40 26 493. developed new concrete additives and specially en- gineered foundations, the structure could not have ©VVV Ltd. 2014 All Rights Reserved been built.

CONTRACTORS WORLD Around the world, countries such as Estonia are CML House playing catch up with the rest of the world and so 7 Bell Mead Sawbridgeworth have to become familiar with construction techniques Herts CM21 9ES that we take for granted. UK Tel: +44 1279 600598 Bridge forming systems, for instance, have to be Email: [email protected] URL: http://.cwmags.com used by fully trained engineers. Therefore, more and more, companies in this sector are providing training, Contractors World Magazines and supple- technical drawings and support services. They are ments are independent publications. The mention of companies and/or products within more sub-contractors than suppliers. the editorial pages or in advertisements does not infer any endorsement by the publisher or editors. If you are involved in such work, we would be in- All editorial is freely given, without conditions terested in receiveing reports on what you are doing and at the sole discretion of the editor. Specifications are given for guidance only for possible inclusion in future issues. and working practices illustrated are not necessarily endorsed by the publishers. This also offers a unique advertising opportunity Other than saving and distributing in complete page formats, copying, reproduction, decoding or disas- to reach the very people with an interest in your sembly of content or computer code by any means solutions. of any part of the publication is prohibited unless prior approval is provided by VVV Ltd in writing. PDF version can be downloaded for personal use only. No part of the publications can be used for promotional purposes. Items may be linked to content on our servers but not embedded into other pages.

Page 2 Contractors World - Formwork Supplement No 2 EDITORIAL CONTENTS

4 Separate Placing Booms Flying To Complete Denver Airport Expansion Like air traffic over busy Denver International Airport, concrete placing booms are flying regularly over the first major expansion at the site since the early 1990s. 7 Estonia: Tartu Bridge Is Big Challenge The bypass round the city of Tartu is a large-scale infrastructure project now under construction.. 9 Warsaw Spire, Warsaw, Poland The Warsaw Spire office complex is currently being constructed in the capital city of Poland. 12 New flood retention reservoir essential Repeated flooding had forced a German town to take flood protection measures. Even 5 - and 10-year floods represented a serious threat. 14 Insulating Concrete Formwork Fast and cost-effective house-building. Mainstream volume housebuilders could benefit from the speed and performance of insulating concrete formwork (ICF). 15 Switzerland’s largest private construction site When faced with the challenge of building a gigantic new production and logistics centre for the contractor again opted for MEVA formwork. 17 Tallest Residential Building in Western Hemisphere Rises High Located on what is dubbed as “Billionaire’s Row,, 432 Park Avenue is a 27.5 x 27.5 m (90 ft x 90 ft) square luxury condo building being erected 426 m (1,398 ft) high. 21 Companies Featured

Contractors World - Formwork Supplement No 2 Page 3 Separate Placing Booms Flying To Complete Denver Airport Expansion

Page 4 Contractors World - Formwork Supplement No 2 ike air traffic over busy Denver International Airport, concrete L placing booms are flying regularly over the first major expansion at the site since the early 1990s. A new 516 room hotel and transit center is being constructed at Denver International Airport by Mortenson, Hunt, Saunders and Brundage-Bone Concrete Pumping is supplying the pumping equipment and expertise. Brundage-Bone is pumping the con- crete on the 65 m² (700,000 ft²) South Terminal Because one of Denver Airport’s iconic tents would have to be re-an- chored to accommodate construction, two “crucifixes”were buried early in the project. “It was quite a process,”explains Josh Joiner,, Brundage-Bone placing boom operations manager. “We had two 39 m boom pumps working simultaneously to fill the 1.8 m Two 39 meter Schwing separate placing (72”) diameter caisson that held the tem- booms with 35 meter horizontal reach porary support. The crucifixes had to be were chosen for the project. After boom aligned perfectly to provide a two-point pumps completed the second level, the anchor for one end of the tent.” booms were attached to 15 m (50 ft) masts that were mounted in base frames The large excavation for the station, and anchored to level one. located at the end of the south terminal, measured approximately 457 m x 274 “Moving the booms could take up to m (500 yds x 300 yds). Hundreds of an hour,”according to Joiner, “Because the caissons were drilled and the voids filled shoring wouldn’t allow the weight of the by Brundage-Bone using Schwing 39 m boom on the deck we had to swing them concrete pumps. off the footprint and set them in a cradle on the ground. After we moved the mast, The 18 m (60 ft) deep drilled caissons we could remount the booms.” each required 23 m³ (30 yds³) of 25 mm (1”) minus aggregate mix. In late 2013, Weight of the SPB 35 is 5,828 kg Brundage-Bone pumped the slab on grade (12,850 lbs) without the powerpack and using “Everything from our Schwing 32 8,505 kg (18,750 lbs) combined. After level meters to our 61 meters,”according to four was completed the booms and masts Joiner. were easily transitioned into floor frames.

Contractors World - Formwork Supplement No 2 Page 5 To clean out the line, crews use 120 psi air pressure generated by a 375 cfm air compressor to blow back the clean out balls into ready-mix trucks through a candy cane- shaped outlet at ground level. After 13 months of pumping, the Brundage-Bone crew is proceeding with the With this mounting method, the masts hotel that is being built on are held in 1,040 mm x 1,0404 mm (41”x top of the transit center. 41”) metal frames with pins and wedges for faster raising and repositioning. “Now the tower crane can pick the boom and powerpack together so flying Feeding the booms from two pumping and remounting only takes a half-hour,”Josh stations are a Schwing BPL 4000 truck- notes. mounted pump or 32 m (105 ft) Schwing – both with 2023-5 pump kits. The placing booms 4-section Roll and Fold boom reaches 35 m (114 ft) hori- The 32 m (105 ft) is bypassing the zontally allowing more than 3,716 m² boom and pumping directly from the Rock (40,000 ft²) to be poured from one location. Valve outlet through a transition and into the pipeline. Two five-inch pipelines are an- For more information: chored horizontally and vertically to reach >>>Schwing America the eight boom locations. The pipelines are five- inch, heavy-duty, heat-treated, one-quarter-inch wall with two-bolt, heavy-duty five-inch clamps. Mix designs ranged from 8,000 psi for the verticals and 5,000 psi for the decks. The BPL 4000 and the S32X averaged 92 m³/h (120 yds./ hr) pumping at the maximum distance of 213 m (700 ft). More than 450 m (1,500 ft) of pipeline is being utilized on the project.

Page 6 Contractors World - Formwork Supplement No 2 Estonia Tartu Bridge Is Big Challenge

The bypass round the city of Tartu experts Doka, a company it has coop- is a large-scale infrastructure erated with over many years. The Doka project now under construction. engineers’ response to the challenge was In terms of formwork engineering, a first in the Baltic region. bridging the Emajõgi River is one The new-build Tartu Bridge will be 400 of the project’s biggest challenges. m long overall and 15.5 m wide. Most of It required detailed planning for the formworking can be done on com- the formwork so they truned to pacted riverbank subsoil with the load- the Austrian company Doka. bearing towers Staxo 100. he steadily increasing volume of The river itself cannot be dammed or traffic in and around Tartu, second even diverted however, so shoring over T largest city in Estonia, with a the full span is not an option. The solution population of about 100,000, requires was to use a high-performing Doka can- new approaches – in this case a new road tilever forming traveller - the first such a network to keep urban traffic flowing. technique had been used in a Baltic state. This road-building project faced a The traveller was used to throw the 55 number of topographical hurdles, chief m middle section of the bridge across the among which is undoubtedly the crossing waters. The concreting sections are 5.1 m of the Emajõgi River. long. To meet this challenge lead contractor Doka formwork instructors were K-MOST AS turned to Austrian formwork in attendance to coordinate setup

Contractors World - Formwork Supplement No 2 Page 7 A Doka cantilever forming traveller is being used for the first time in the Baltic region on the Tartu Bridge build.

Doka formwork instructors were in attendance to coordinate setup and familiarise the site crew with the procedures.

and familiarise the site crew with the the project owner benefits from the Doka procedures. Group’s rental model. A formwork instructor was also on Instead of being bought outright, the site for the cantilever forming traveller’s formwork system is simply hired for the first advance, to make sure that everything duration. Usage of the formwork system went smoothly. is billed by the day and the equipment is From the second concreting section on, returned as soon as the job is done. the site crew was well able to take charge This major infrastructure project is of the advancing procedure without further scheduled for completion by the end of assistance. 2015.

The cantilever forming traveller will For more information: be on site for only a very short time, so Doka Formwork

Page 8 Contractors World - Formwork Supplement No 2 Warsaw Spire, Warsaw, Poland

he Warsaw Spire office complex is the floors feature an elliptical ground plan currently being constructed in the which varies from floor to floor. The shell T capital city of Poland. The 220 m is 188 m high and, with the addition of the high, waist‑like office tower complete with eponymous “Spire”, the building reaches elliptical ground plan characterizes the ap- its planned overall height. pearance of the building complex - the The German formwork specialists, Peri tower is flanked by a 55 m high building on has planned and supplied the complete each side. formwork and scaffolding solution for the Three structures form the new building complex. This includes the self‑climbing complex: a 220 m high tower is flanked formwork for the core as well as a full‑pe- by two semicircular buildings, each 55 m rimeter climbing protection panel. high. Designed by the Belgian architects During the project development phase, Jaspers Eyers & Partners, the tower is Peri worked closely with the investor and very distinctive due to its special shape: general contractor, Ghelamco Poland,

The shell enclosing the RCS climbing protection panel is completely enclosed and has provided safe working conditions at all heights and in all weathers.

Contractors World - Formwork Supplement No 2 Page 9 With the customized VARIO GT 24 girder formwork, the construction team achieved the required, high‑quality surfaces of partly elliptical core walls

and shell contractor, Monting, in order walls, Peri engineers combined the ACS to create the most efficient formwork self‑climbing variants with platform. The solution that could produce the planned platform system has generous storage and architectural design safely. working areas for the core walls, which are formed in advance. Customized climbing solution The formwork for the semi‑circular The major challenge for the climbing system outer walls of the core is suspended on the was its ability to adapt to the variable el- variant with gallows. With the VARIO GT liptically-shaped storey slabs. Furthermore, 24 girder wall formwork, the construction a weekly cycle per floor was necessary to team has achieved a high degree of dimen- maintain the short construction period. sional accuracy as well as particularly good The rail climbing system adopted pro- wall surfaces. vided the flexibility needed. For anchoring An RCS landing platform is also being to the floor slabs, horizontally cantilevered used. RCS climbing rails have been used. Using rentable system components These make accommodating the taken from the VARIOKIT engineering varying length of cantilevers possible and construction kit, the RCS platform pro- thus easily compensate for the projections vides an ideal erection area for a 4‑ and and recesses in place between the floor 6-storey stair slabs. At the same time, anchoring ensures that the protection panel is always se- curely connected to the building. As the floor slabs of the Warsaw Spire have to be pre‑tensioned, the climbing protection The mobile panel has been designed with three plat- climbing units forms. This offers access on all sides of the lift the enclosure building to the designated working areas (rail guided) on the front sides of the slabs. in 50 cm increments from For the formwork for the core floor to floor.

Page 10 Contractors World - Formwork Supplement No 2 SKYDECK system supports rapid and systematic forming of large slab areas.

tower. As SKYDECK is equipped with drop The Peri UP stair construction gives heads, striking the slabs can take place continuous access to the top floors, re- earlier. This means panels and main beams gardless of how the assembly of the precast are available at an early stage for the fol- stairs in the building core is progressing. lowing sections. The advantage for the site management is that on‑site material The climbing formwork as well as the requirements are significantly reduced. climbing protection panel move from floor to floor without the need of a crane: the For the two flanking office towers, the ACS self‑climbing formwork functions SKYDECK system is supplemented at using a climbing device with 100 kN lifting the slab edges with slab tables. These are power while the RCS climbing protection quickly lifted to the next storey each time panel is lifted upwards by means of mobile in one crane lift together with attached climbing devices. PROKIT edge protection and the mounted supports. Proven standard solutions for columns and slabs Formwork, scaffolding and engineering from one source For the circular columns of all three buildings, the construction team achieved Peri has been supporting the formwork best concrete surfaces with steel SRS and scaffolding activities for the Warsaw circular column formwork. For all rectan- Spire in numerous ways. gular columns, TRIO column elements are During construction of the building’s being used. shell, the local Peri rental park supplied The large slab areas feature a wide the required quantities of materials to range of elliptically‑shaped ground plans enable the contractors to keep to the tight and are formed with the SKYDECK panel schedule. The work on the facade is being slab formwork. The aluminium system fea- carried out using Peri UP scaffolding. tures particularly lightweight and practical For more information: system components. Furthermore, the >>> Peri Formwork & Scaffolding simple and systematic assembly accel- erates the formworking activities.

Contractors World - Formwork Supplement No 2 Page 11 The outer walls of the culvert, which will be in the middle of the dam, are angled inwards at 2.86 degrees. The side wings (in the rear of the picture) are strongly tapered. The base plate also has a noticeable slope. This presented no problems for the LOGO.3 formwork system and Früh Ingenieurbau

(mountain stream) and a larger one near Haslach-Ost; other local extensions are also to be added. The most interesting con- struction project from a structural engineering point of view is the one at Haslach-Ost, which com- pletely blocks off the Mühlbachtal with a 360 m long earth dam of up to 8.8 m in height. In its rear, a flood retention area of 370,000 m³ is created, which covers an area of New flood 12 hectares at maximum water levels. Concrete structure and dam retention The fill earthworks on the 35,000 m³ dam was advanced to just short of the culvert reservoir construction site, because the dam could not be joined to the concrete structure essential and be completed until all work on the Repeated flooding had forced the German culvert has been completed. town of Haslach, in the district Ortenaukreis, As lead construction company, Früh Baden-Württemberg and the neighbouring Ingenieurbau GmbH & Co. KG (Achern) community of Hofstetten,to take flood began with the structural work on the two protection measures. Even 5 - and 10-year 1 m thick floor slabs made of C35/45 SM 31 floods represented a serious threat. of 243 m³ (with 32 tons of reinforcement) The most practical and economic so- and 530 m³ (40 tons ). lution for protection from a hundred The culvert, which will be right in the year flood is to build a smaller reservoir center of the dam, consists of a 21.10 m in Hofstetten on the Hofstetter Talbach

Page 12 Contractors World - Formwork Supplement No 2 The almost 60 m wide construction site from the dam, which will soon reach the walls. Mühlbach creek is flowing from left to right. Here, the placing formwork is 10.20 m high.

formwork to a minimum and to optimally bring the amount of formwork in line with job site conditions, eight formwork cycles were chosen with an additional half a cycle of formwork modules being provided to work ahead. This method with only 442 m² of formwork promised the highest efficiency. The LOGO.3 formwork system by Foreman Walter Lauber explains a job PASCHAL was used, which was particu- on the reinforcement to his people. The larly well suited for this purpose , having closing formwork is just being erected. already been used for many similar pro- jects without any problems. long horizontal front section and a 32.40 m The majority of the formwork area long sloping section split longitudinally was covered by large elements, 3.40 m in into two 5.55 m wide parts, with one of height and 2.40 m in width. the parts being one level lower and func- tioning as a spillway. The slope is 45 cm. To provide the best possible formwork on a slope and to allow for surface The two retaining walls of the culvert treatment afterwards, elements of nine are sitting on the sloping part of the foun- different dimensions were used overall, dation and taper in thickness from 1.30 m the smallest measured only 50 cm x 75 cm. at the base of the central area to 0.70 m at the top; the wings on the outer sides are The biggest pouring height of 11.90 m also only 0.50 m thick. The conical walls was achieved by using three 3.40 m ele- are angled inwards at 2.86º at the outer ments and one 1.35 m element (each 2.40 surfaces. m in width), the latter was in addition topped off with a 1.35 m wide and 75 cm A small ring road is to run on top of high horizontal element at the sides. the dam; a small bridge will be built a few meters downstream. Concrete and formwork For more information: >>> Paschal Formwork To keep the costs for the concrete

Contractors World - Formwork Supplement No 2 Page 13 Insulating Concrete Formwork Fast and cost-effective house-building Mainstream volume housebuilders could benefit from the speed and performance of insulating concrete formwork (ICF). ICF, also known as permanently insulated Courtesy of Amvic of Sutton Park, Leeds formwork (PIF), is an innovative modern method of construction. 4 m² per man hour. This equates to the ICF structure of a five bedroom detached Led by the self-build and social housing house being built in just two weeks. sectors, the construction method consists of twin-walled expanded polystyrene (ESP) There is also minimum waste, as off-cuts or extruded polystyrene (XPS) blocks, from ICF block and panel elements are panels or composites, connected by plastic collected on site and recycled directly into or metal connectors and then filled with the manufacture of new elements. ICF also ready-mixed concrete. has an inherent adaptability, so contem- porary architectural and traditional ver- The system combines the inherent nacular designs are easily accommodated. strength and performance with the excellent thermal insu- Any form of external finish, such as ma- lation properties of polystyrene. sonry, brick-slips, render, tiles or weather- boarding, can also be affixed. For volume housebuilders, it’s the speed ICF can offer that is significant, with up to ICF can provide U-values in the range of 0.11 to 0.35W/m²K. In addition to high levels of insulation, ICF structures have very low air infil- tration rates.

For more information >>> The Concrete Centre

The early stages of ICF construction show its superb design flexibility and ease of construction benefits. Image courtesy of ICF Tech Ltd.

Page 14 Contractors World - Formwork Supplement No 2 Switzerland’s largest private construction site

hen faced with the challenge Over 100 workers pour different building of building a gigantic new pro- parts in the enormous building pit. The duction and logistics centre concrete is produced on site and pumped W to the formwork or carried by concrete for the Swiss Coop Group, Zurich-based lorries and distributed by placing booms. contractor Marti, who has used MEVA formwork for a number of large-size com- workers simultaneously pour different mercial buildings, again opted for MEVA building parts to meet the tight deadline formwork. – assisted by six cranes, on-site concrete production facilities and the high-perfor- The new production and logistics mance Mammut 350 wall formwork that centre with 14 floors on an area measuring offers them triple time savings on this site. 300 by 100 metres will offer a gross floor space of 240,000 m² and a building volume First, the walls, shafts and columns that of 1.5m m³, for logistics, distribution and come in different sizes can be poured production facilities, the national cold without the need for time-consuming job- store, returned empties handling facilities, built fillers and special solutions. This also Switzerland’s largest bakery, offices and optimizes the utilization of the formwork 1,300 parking lots. on site. Speedy pours thanks to Second, the system’s largest panel is triple time savings 3.50 m high and, thus needs only one height extension to pour the 4.15 m high walls. The new facility is scheduled for oper- This drastically reduces assembly times. ation in late 2015. Day after day, over 100

Contractors World - Formwork Supplement No 2 Page 15 The wide selection of Mammut 350 panels is used to pour walls, shafts and columns in different sizes without the need for time-consuming job-built fillers or special solutions.

Third, the Mammut 350 handles fresh concrete loads of up to 100 kN/m² and allows for an unlimited rate of pouring up to 4 m. With many building parts being poured simultaneously and over 3,000 m² of formwork in use, the time savings are considerable. Fast climbing: one staircase level in only half a day KLK 230 climbing scaffolds and approximately one hundred KAB 190 working platforms are used to climb the shafts and walls. With the KLK 230, the wall formwork is attached with a slide carriage to the KLK 230 platform. The walls are climbed with the Mammut This way, the wall formwork can easily 350 wall formwork on working platforms KAB 190 while the shafts are climbed be moved back by 70 cm for installing the with the KLK 230 climbing scaffolds. The steel . heavy prefab columns in the front are These units, including the wall formwork, supported by Triplex-R heavy duty braces. can be crane-lifted as one single unit, saving even more time and allowing one complete prefab parts and formwork that efficiently staircase formwork to climb by one level and quickly handles all the many pours, the in only half a day. contractor has been making fast progress and met all deadlines without compro- Clever combination allows mising quality. for fast progress The first three basement floors were The slabs are semi-prefabricated and sup- finished by the end of 2013, and, floor by ported by prefab columns that weigh up 15 floor, the building complex is growing to- tons and are up to 13 m high. The columns wards its future use. are supported by MEVA’s Triplex-R heavy duty braces until they are stabilized by the For more information: slabs. >>> Meva Formwork Thanks to a clever combination of

Page 16 Contractors World - Formwork Supplement No 2 Tallest Residential Building in Western Hemisphere Rises High

Located on what is dubbed as “Billionaire’s Row,”432 Park Avenue is a 27.5 x 27.5 m (90 ft x 90 ft) square luxury condo building being erected 426 m (1,398 ft) high. When complete, it will be the tallest residential building in New York City and in the Western Hemisphere. Building up and setting records does not occur without some key chal- lenges, especially related to safety. As such, Roger & Sons Concrete, Inc., the concrete contractor on the project, selected Doka to provide the high-end formwork solutions, fast service and safe practices to keep the project on schedule. Located between 56th and 57th streets, the 96 story building is situated in a neighbourhood known for art, fashion and retail. The 104 unit build- ing’s condos range in price from $7 million to $95 million and will include an exclusive 790 m² (8,500 ft²) private restaurant that will serve three meals a day only to the condo owners and their

Photo: Louis B

Contractors World - Formwork Supplement No 2 Page 17 guests. Other notable building fea- tures and amenities include trademark square windows, private lift landings, separate service entrances, 385 mm (12.6 ft )ceilings, and a 23 m (75 ft) indoor swimming pool. Custom, architectural steel formwork is being used all around the outside column and the spandrel beams in the form of stainless steel. Construction began in September 2011 and Doka quickly implemented many of their formwork solutions to keep all members of the construction team safe. Doka’s load-bearing Staxo 100, de- signed for tall shoring-heights and high loads, is being used because of its ability to unite high-load capacity and safety. The system’s very high load-bearing capacity – up to 10,205 kg (22,500 lbs) per leg – has optimized use of equipment for this project. Staxo 100 built-in protective fea- tures, including safe up/down access assured by ladders with slip-resistant rungs in- tegrated into the frames; individual safety is aided by clearly defined anchorage points for personal fall arrest systems; and safe erection and dismantling ensured by “mounted-ahead”railings. In addition, Doka’s Super Climber combined with Framax is being used as the self-climbing core formwork.

Page 18 Contractors World - Formwork Supplement No 2 Both systems provide safe wide working plat- forms for the interior and exterior of the core construction to ensure safety during working operations and for up- and-down access. Doka’s Super Climber also provides integrated platforms, stair towers and ladders. It uses a single stroke cylinder to move the core with forms, concrete placing – the latter a first, as such a high modulus boom and multiple levels of working plat- of elasticity had never before been spec- forms up to the next casting step. ified for a residential building. All of the formwork for an entire story The specifications also required a is raised independently of the crane. The self‑compacting concrete with a slump – system allows the inside and outside forms or flow, that is – of at least 76 centimetres to be hung from the gantry, which enables that was not to exceed a temperature the contractor to roll forms away from limit of 71° Celsius during hydration and core walls, while erecting and stripping. was to retain its performance properties There is no need to strip forms into during construction at all conceivable units, which keeps the core forms as a temperatures. single unit. This cuts down on labour costs In addition, the concrete was to show and speeds up construction cycle. high early strength development with “This building will be a landmark…rising surfaces walkable only five hours after out of Midtown like a pencil sticking up in placement of the material. the air twice as high as anything else in the Further requirements included the neighbourhood,”says Antonio Rodrigues, pumpability of the concrete across the President of Roger & Sons Concrete, Inc., entire height of the structure, even after the contractor for the project. transport times of up to two hours. New concrete formula essential This requirement, however, was in direct opposition to another: the white The requirements on the concrete for this colour of the concrete. landmark project were a step into new territory in many respects. Normally, this goes along with trade‑offs in workability, among others. The material was to exhibit a com- But the colour was mandatory – as was a pressive strength of 110 N/mm² and a smooth, fine‑pored, perfect fairfaced con- modulus of elasticity of 53,000 N/mm² crete quality without any discolouration

Contractors World - Formwork Supplement No 2 Page 19 or visible cracks. to come together; rheology and min- Probably the biggest challenge, however, eralogy play important parts, as do hy- was in obtaining all these characteristics at draulics, hydromechanics and pore‑water the lowest‑possible content. composition.” Clearly a case for the experts of the After a series of tests, both in the North American Admixture Systems laboratory and on‑site in Manhattan, the team and their Green Sense Concrete concrete finally yielded the desired- per technology, which has successfully, and formance properties – even though a con- impressively, proven its efficiency on the siderable part of the had One World Trade Center, among other been replaced with alternative binders. projects. A few trials later, the team had also “But a bundle of requirements such adjusted the mix design in terms of pump- as this one was new even for us”, says ability and consistency retention. Andreas Tselebidis, Director Sustainable An additional plus for Concrete Technology and Solutions in the environment The mix design only requires locally available raw materials. Upon completion, the building will receive LEED certification – this has already been ascertained. This combination of highest perfor- mance and sustainability, of product quality and dedicated customer service makes the EB proposition so unique – as unique, in fact, as the buildings created with its help. “Without our solutions and our ex- North America. pertise, the construction of 432 Park An important piece of the puzzle was Avenue would not have been possible provided by the colleagues from the Paper at this point in time in quite this way”, Chemicals division: MetaMax, a highly re- Tselebidis says. active and an EPN product,, “And yes, we do take pride in that.” which ensures the consistent white colour The concrete is delivered by truck and of the concrete and, what is more, im- then pumped or carried with concrete proves its compressive strength as well. bucket depending on location, timing, etc. However, harmonizing all requirements The project is scheduled for completion and meeting them completely required all in 2016. the expertise of EB’s concrete admixtures experts. “Ultimately, there is no simple so- For more information: lution to a complex challenge of this kind”, >>> Doka USA Tselebidis clarifies. >>> BASF Admixtures “Here, physics and chemistry have

Page 20 Contractors World - Formwork Supplement No 2 Companies Featured click for contact details

• BASF Admixtures

• Concrete Centre, The

• Doka Formwork

• Meva Formwork

• Paschal Formwork

• Peri Formwork & Scaffolding

• Schwing America

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