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installation, so the design would not be able to take full advantage of the property footprint. A Type B solution was ultimately selected for this project. Kryton’s Krystol Internal Membrane (KIM), a hydrophilic crystalline concrete water- proofing admixture, was chosen for its workability and quality control. As a product fully meeting the requirements of the American Concrete Institute’s (ACI’s) standard classification of permeability-reducing admixtures under hydro- static conditions (PRAHs), KIM was the perfect choice for this type of application. A Unique Approach Abbey Pynford, a company specializing in ground engineering work, was brought on board to execute the tricky basement construction. With 25 years of experience in specialist ground engi- neering, a new innovative piling design and The integral crystalline waterproofing method also improved the shotcrete technique was developed and designed specifi- mixture’s workability and gave the finished product a smoother cally for this job. This technique—combining the architectural appearance (Photo courtesy of Abbey Pynford—Basement process of mini pile installation, using sectional Engineering Specialists) auger bore string with plunged UC structural steel sections—was necessary to ensure that the base- ment area could be excavated safely. It was critical that this was accomplished without damaging the two bordering properties, but at the same time providing the absolute maximum internal space. The pile was formed by a restricted access rig weighing 1.7 tonnes (3750 lb) drilling into the ground with an auger string to the required depth. A pre-blended micro-concrete mixture was then pumped down the open pile bore whilst the struc- tural steel section was plunged. A shaft of micro concrete was thus formed, reinforced with a structural steel section. This unique technique enabled the perimeter of the basement to be formed with the piles retaining the adjacent soils. It also enabled the structures with piles to be half the depth and 70% the width of those formed using traditional steel reinforcement. When it came to deciding on the best method of concrete application to form the internal rein- forced concrete lining wall for the installed piles, Using shotcrete and KIM together allowed the basement to be constructed Abbey Pynford turned to a shotcrete application. right to the property line without affecting the neighboring homes (Photo Lining the walls with shotcrete carried the benefit courtesy of Abbey Pynford—Basement Engineering Specialists) of minimizing the joints in the concrete and accel- erating production time. Speeding up the wall installation by using shotcrete significantly reduced costs associated with labor and materials 1. Kryton’s KIM HS, Treatment and External Grout that would have been needed to erect formwork enabled Abbey Pynford to use their existing for a cast-in-place method. design without alterations. KIM is known to be very compatible with 2. Kryton’s KIM HS was perfect for sprayed concrete shotcrete, not only by waterproofing permanently application to save time and money. and effectively but also by improving workability. 3. Private client is very happy with the finish of the The proprietary admixture effectively makes the concrete and was impressed with the speed of shotcrete mixture more plastic and allows creation installation. of a higher-end architectural finish to the concrete Shotcrete • Spring 2014 13


2014SprShotcreteEMag
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