What is the best reference when specifying aggregate gradations for shotcrete projects?
ASTM C 33 contains a variety of aggregate gradations. Gradations recommended for shotcrete applications can be found in ASTM C 1436, Standard Specification for Materials for Shotcrete, or ACI 506, Guide to Shotcrete. Note that ACI 506 includes the caveat that “aggregates failing to comply with gradations shown in Table 2.1 may be used if preconstruction testing proves that they give satisfactory results or if acceptable service records are available.” (back to top) Question 54: I want to apply a 3.5 in. (89 mm) veneer of shotcrete over an existing cast-in-place wall. I am concerned about how well the shotcrete will bond to the existing wall. This wall is 50 ft (15.25 m) in height. What are the keys to doing this work successfully? Answer: This is a common use for shotcrete. The key elements are as follows. 1. Proper surface preparation. To establish suitable surface roughness, use heavy-duty sandblasting, high-pressure water blasting, or mechanical methods such as scabblers or scarifie
