S ec t i o n 5 -P a g e5 May 2013 Fillet on Forged Head Rebar - For ged head r ebar bolts should be inspected to ensur e a fllet of 1 / 8 "radius is pr esent wher e the shaft connects to the for ged head. Sharp transitions may weaken the bolt. Shelf Life of Resin - Resin has a practical shelf life. Although the chemical ingr edients do not change with time, most r esin cartridges ar e water based and thus dry out with age. The shelf life thus r efers to the workability of the r esin cartridge. Aged cartridges ar e still ef fective; however , because they ar e drier , the ingr edients ar e crumbly and har der to mix pr operly . The bolts ar e mor e dif fcult to insert thr ough old r esin as well. Set times may also be r educed somewhat with older r esin. The r esin cartridge box will have the manufacturing date written on it. Resin should be used as soon as possible. Stock should be r otated so older r esin does not accumulate. Storage - Resin should be stor ed in a cool location to maximize shelf life. Elevated temperatur es dry out the r esin cartridges. T emperatur e and Set Time - T emperatur e gr eatly af fects the gel (set) time of r esin cartridges. A 20F rise in temperatur e r educes the set time by appr oximately 50 Conversely , a 20F dr op in temperatur e will appr oximately double the set time of the r esin. Resin should be stor ed and used at r oom temperatur e whenever possible. continued Installation Quality Guidelines Rebar and DYWIDAG THREADBAR ® Bolts The following ar e items to be awar e of when using/installing r esin gr outed r ebar and DYWIDAG r ock bolts: T ype of Gr ound - The natur e of the gr ound must be evaluated. Soft strata r equir es a lar ger plate washer bearing ar ea and a longer anchorage length if point anchor ed. Soft gr ound r esults in lar ger hole sizes for a given bit size (due to bit rattling and r eaming). This can adversely af fect the mixing of the r esin. Scaling - The gr ound should be thor oughly scaled i.e. barr ed down, befor e drilling and bolting. Periodic r e-scaling may be r equir ed while drilling. Str ength and Y ield Capacity of Bolt - The mechanical pr operties of the bolt should be appr opriate for the gr ound conditions, bolt length and bolting patter n. Pull tests should be performed to determine yield and ultimate str engths of the bolts as well as r esin anchorage capacities. Condition of Rebar Thr eads - Thr eaded r ebar should be inspected befor e installation. Incr eased friction on the thr eads can adversely af fect tensioning of the r ebar . DYWIDAG thr eads a re generally immune to defects and damage. www .dsiundergr ound.com