Main information at a glance
Non-explosive cracking agent DYNACEM is a grey powder that needs to be thoroughly mixed with water prior to filling the holes previously drilled in the element intended for demolition. As a result of a chemical reaction (hydration with heat evolution) DYNACEM hardens, anchors itself within the holes and expands. Volume increase is accompanied by an increase in pressure exerted by DYNACEM on the walls of the hole. Once the pressure exceeds the tensile strength of the element, cracks begin to form. They keep on growing as the cracking agent keeps on expanding. Pressure exerted by DYNACEM is a couple of times higher than the tensile strength of concrete, mineral construction materials and rocks. Further propagation of cracks can be accelerated by providing moisture to the holes.
Dynacem expansion pressure is thoroughly tested by our laboratory for each produced batch of product before it is qualified for sale - see Appendix to Dynacem Data Sheet.
Non-explosive cracking agent DYNACEM is available in versions: STANDARD for temperatures -10 - 15 ºC, SUMMER for 10 - 30 ºC and SUMMER+ for 30 - 50 ºC. Each version is slower and weaker performing at the bottom or below of its temperature range and faster and stronger performing at the top of its temperature range. Do not use any of these Dynacem types above their temperature range.
The time to crack formation usually ranges from a few to 24 hours. The key factors are: hole size, temperature and properties of the material being cracked. Hard and rigid materials (e.g. high strength concrete) usually fracture more easily than soft materials (e.g. lean concrete) that tend to deform, rather than break under pressure.
30 - 40 mm diameter holes spaced 5 - 15 diameters away (15 - 60 cm) provide effective cracking capabilities in most practical applications. It is, however, best to account for element temperature (measured within the hole) and the type of material being cracked (concrete, r.c., rocks) in each case individually following the guidelines in the table:
|Set-up depending on temperature:||element temperature measured within the hole|
|below 0 ºC - 10 ºC - 15 ºC||10 - 30 ºC||30 - 50 ºC|
|- DYNACEM type||STANDARD||SUMMER||SUMMER+|
|- hole diameter: reinforced concrete, hard rock||5 cm 4 cm 4 cm||4 cm||4 cm|
|- hole diameter: non-reinforced concrete, soft rock||4 - 5 cm 4 cm 3 cm||3 cm||3 cm|
|- hole spacing: reinforced concrete, hard rock||5 - 10 hole diameters|
|- hole spacing: non-reinforced concrete / soft rock||10 - 15 / 10 - 20 hole diameters|
CAUTION, increased hole diameter will result in higher DYNACEM chemical reaction rate. A diameter, which is too large may cause the mixture to dangerously blow out of the holes, especially in the summer.
Only use the product according to instructions of Data Sheet and Material Safety Data Sheet.
When dealing with non-reinforced elements DYNACEM expansive grout can sometimes be successfully applied to holes of a diameter smaller than those given in the Table, especially when it's warm outside and the holes are arranged in a linear pattern, or when increased cracking time is acceptable.