A Short History of Shotcrete

 

Shotcrete is pneumatically placed concrete that is used as an economical alternative to traditional cast-in-place walls.  As it almost eliminates the forming process all together, it greatly reduces labor cost and time.  Shotcrete has the same structural characteristics as traditional cast-in-place walls and a wide range of applications including shear walls, retaining walls, architectural walls, slope pavement, and soil nailing. 

Wikipedia reports that shotcrete, originally known as gunite, was first used to repair the crumbling façade of the Field Columbian Museum in Chicago in 1907 by a well-known naturalist, Dr. Carl E. Akely.  He used a process where dry material was blown out of a hose and water was injected from the nozzle.  Mr. Akeley later went on to patent the equipment, which was called a cement gun, and the material called Gunite.  The Cement Gun Company was soon started (now called Allentown Equipment).

It was not until mid-1950 that a wet mix method was introduced to the construction industry.  Right from the start the benefits were recognized and it was successfully used on many projects.  Shotcrete really took off from there with the development of a rotary gun that had an open hopper, which allowed the material to be continuously fed.    

The American Shotcrete Association credits the technical advancements in materials and equipment made during the 1970’s of providing a huge improvement in the applications of shotcrete.  They report that, “The Engineering Foundation organized the first conference for The Use of Shotcrete for Underground Support.”  Furthermore, they write that, “Perhaps the most significant step in this period was the development of efficient concrete pumps that could be used for wet shotcrete application.”

The 1980’s saw advancements in the mixing and batching of ready mix concrete with developments of admixtures that allowed for consistency, hydration and performance.  One of the biggest changes in the shotcrete that is used today is the ability of equipment to pump any slump and to be able to pump it over long distances and up into high rise construction projects.  

* http://en.wikipedia.org/wiki/Shotcrete

* http://www.shotcrete.us/

* source: American Shotcrete Association

Conco is taking a more active role in the Portland area with our expansion of high-quality commercial concrete services.  We bring our years of experience delivering dependable services since 1959, and a vast portfolio of noteworthy and large-scale projects from throughout the Western U.S.  Our work includes commercial, industrial, educational and multi-residential construction as well as public works projects.