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2013WinShotcreteEMag

Fig. 4: The same element when finished the wall elements underwent destructive dry-mix shotcreting machine was used and pumps testing, including a cut-out of the finished wall with provided water to the nozzle. Dry-mix shotcrete the anchorage. The test of the wall’s fire resistance was prepared internally at Torkret’s custom mixing was also crucial. It must be emphasized that the plant with a dedicated production unit designed wall is not merely a decorative element or work specifically for the curvilinear wall construction. of art but also a partition between walking routes The first course was shot using a traditional shot- for visitors and technical and office premises. The crete mixture based on rounded quartz aggregates EI30 test was made on test elements in the Fire and portland cement. The second phase was also Testing Laboratory of the Building Research made based on a selection of quartz aggregates, but Institute, Warsaw (refer to Fig. 3 and 4). the binding material was white cement with closely Another innovative element was specially matched coloring. According to the designers’ wish, designed plastic strips embedded both in expan- the wall color was to reflect the color of rocks in sion joints and control joints. The structure of the Israel. The color was inspired by the color of the plastic strips facilitated maintaining a constant Western Wall in Jerusalem. This shade was obtained shotcrete application layer thickness and delin- by mixing white cement and suitable dyes. eated the outer surface. This also enabled instal- Maintaining a uniform color was one of the lation of a membrane, preventing humidity loss biggest challenges. Having experienced with and protection against dust when applying onto similar applications, Torkret knew that different the adjacent element. The expansion joint strips shades may occur on the resultant surface. Indeed were removed and replaced by fireproof silicone different shades did occur, but they only added to material. The control joint strips were left in the the wall’s special features. structure reflecting the so-called wall pattern Many execution-related issues were faced when assumed by the architect (refer to Fig. 5). building the project. A major part of the wall’s surface The most important issue from the wall profile area was made in the open space of the building. shaping perspective was transferring the 3-D Installation of the roof covering and a glazed window design coordinates to the wall modeling space. (approximately 6500 ft2 600 m2) and the entrance This was achieved by continuous layout of the structure weren’t completed until the end of the points of crossing of joints or other typical points. project. This forced us to organize our work so that Strips were mounted on a special plate serving as the preliminary stages were prepared during periods a stay-in-place form. The plate had to meet the of lowered temperature while the application of elasticity (multi-directional bending) and non- shotcrete was conducted during advantageous flammability conditions. Once the plate with weather conditions. A major execution-related prob- joint-defining strips was formed and fastened, two lem was access to individual wall elements. Place- layers of concrete were applied. An Aliva 246 ment of a frame scaffolding that offered constant 14 Shotcrete • Winter 2013


2013WinShotcreteEMag
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