1 Renderoc hb40 : 8/2003 Renderoc hb40 High performance medium-weight concretereinstatement mortarUsesRenderoc hb40 exhibits a series of performancecharacteristics designed to achieve maximum compatibilitywith concrete with a compressive strength greater than30 the reinstatement of large areas of reinforced concretewhere low permeability characteristics are required and wherehigher compressive strength is an important hb40 has been engineered for the repair of columnsand beams but, because of its relatively low fresh wet density,is also suitable for soffits and other overhead repair work. The mortar can also be used for small, localised patch compatibility with lower strength concrete is required,but low permeability and high-build characteristics areimportant, Renderoc HB25 should be note: this mortar is approved foruse with Norcure realkalisation.
2 When usingit in conjunction with this method, theconcrete bonding primer should be anOPC:water slurry. Polymer bonding agentsshould not be used. No steel primer shouldbe applied. Refer to your local Parchemsales office for further Maximum compatibility with concrete of compressivestrength greater than 30 MPa High-build applications possible while maintaininghigher compressive strengths - fewer cold joints Frequently obviates the need for formwork Polymer-modification provides extremely lowpermeability to water, carbon dioxide and chlorides Exceptional system of shrinkage compensationprovides long-term dimensional stability Can be applied quickly and efficiently by wet spraying One component, pre-bagged to overcome site-batchedvariations Contains no chloride admixtures Suitable for internal and external applicationsStandards complianceRenderoc hb40 has been tested and approved inaccordance with the Hong Kong Housing AuthoritySpecification TM1 to TM8 (1990) and ASTM C596-89(modified 23 C, RH50%).
3 DescriptionRenderoc hb40 concrete reinstatement mortar is suppliedas a ready to use blend of dry powders which requires onlythe site addition of clean water to produce a highlyconsistent, medium-weight repair mortar. It is based onPortland cements, graded aggregates, lightweight fillersand chemical additives which provide a mortar with goodhandling characteristics while minimising water low water requirement ensures good strength gain andlong-term supportParchem offers a comprehensive range of highperformance, high quality construction products. Inaddition, Parchem offers a technical support package tospecifiers, end-users and contractors, as well as on-sitetechnical criteriaRenderoc hb40 exhibits a series of performancecharacteristics designed to achieve maximum compatibilitywith concrete with a compressive strength greater than30 hb40 has been engineered for the repair ofcolumns and beams, but, because of its relatively low freshwet density, can readily be used for vertical and overheadrepair work.
4 It can be applied in sections up to 40 mmthickness in vertical locations and up to 30 mm thickness inoverhead locations in a single application and without theuse of formwork. Thicker sections can be achieved by theuse of formwork or can be built up in layers. Deep pocketscan sometimes be filled in a single application dependenton the configuration of the pocket and the volume ofexposed reinforcing can be dramatically increased by wet achievable thicknesses are 70 to 110 mm verticallyand 60 to 85 mm overhead, although this will depend onsubstrate profiles and the distribution of steelreinforcement. Consult your local Parchem sales office forfurther material should not be applied at less than 10 strengths below 30 MPa and/or higher builds arerequired, Renderoc HB25 should be following results were obtained at a water:powder ratioof and a temperature of 20 C unless otherwise methodTypical resultCompressive strength(BS 6319 Pt 2: 1983-dry cure):10 MPa @ 1 day25 MPa @ 7 days35 MPa @ 28 daysFlexural strength(BS 6319 Pt 3: 1990) MPa @ 28 daysTensile strength(BS 6319 Pt 7: 1985) MPa @ 28 daysModulus of elasticity incompression(BS 6319 Pt 6: 1984):18 kN/mm2 @ 28 daysWater absorptionISAT (BS 1881 Pt 5: 1970)10 ml/m2/sec2 ml/m2/secDrying shrinkage23 C/RH50% (ASTM).
5 < 400 microstrain @ 7 days< 600 microstrain @ 28 daysCarbon dioxide barrier -equivalent thickness of concreteto Renderoc hb40 @ 10 mm(Taywood method):600 mmChloride diffusion byTaywood bulk diffusion test(accelerated):< 5 x 10-13 m2 s-1(low permeabilityconcrete defined as< 1 x 10-12 m2 s-1 bynon accelerated testing)Coefficient of thermalexpansion:11 x 10-6/ CSetting time(BS 4551 Pt 14: 1980)initial set:3 hoursfinal set:5 hoursFire rating(BS 476 Pt 4: 1970):Non combustible(Class 0 surface)Fresh wet density:Approximately 1780 kg/m3dependent on actualconsistency resistance:The low permeability ofRenderoc hb40 severelyretards chemical attack inaggressive cured mortar is highlyimpermeable to acidgases, water bornechloride ions, and clausesSteel reinforcement primerThe steel reinforcement primer shall be Nitoprime Zincrich*,a single component zinc-rich epoxy resin.
6 The primer shallbe an active type, capable of avoiding the generation ofincipient anodes in the immediately adjacent locations. Itshall be fully compatible with the Renderoc system ofconcrete concrete reinstatement mortarThe reinstatement mortar shall be a single componentpolymer-modified, cement-based blend of powders towhich only the site-addition of clean water shall bepermitted. It shall be manufactured to achieve maximumcompatibility with reinforced concrete with a compressivestrength greater than 30 MPa and as a consequence, shallexhibit the following characteristics when tested to thestandards and grease deposits should be removed by steamcleaning, detergent scrubbing or the use of a proprietarydegreaser. The effectiveness of decontamination shouldthen be assessed by a pull-off fully any corroded steel in the repair area andremove all loose scale and corrosion deposits.
7 Steelshould be cleaned to a bright condition paying particularattention to the back of exposed steel bars. Abrasive-blasting is recommended for this corrosion has occurred due to the presence ofchlorides, the steel should be high-pressure washed withclean water immediately after abrasive-blasting to removecorrosion products from pits and imperfections within steel primingApply one full coat of Nitoprime Zincrich and allow to drybefore continuing. If any doubt exists about havingachieved an unbroken coating, a second applicationshould be made and, again, allowed to dry primingThe substrate should be thoroughly soaked with cleanwater and any excess removed prior to applying one coatof Nitobond HAR* primer and scrubbing it well into thesurface. Renderoc hb40 can be applied as soon as theprimer becomes tacky.
8 If the Nitobond HAR is too wet,overhead and vertical build up of the Renderoc HB40mortar may be exceptional circumstances, where a substrate/repairbarrier is required or where the substrate is wet or likely toremain permanently damp, Nitobond EP* bonding aidshould be used. Contact your local Parchem sales office forfurther : Nitobond HAR primer should not be used whenspraying Renderoc should be taken to ensure that Renderoc hb40 isthoroughly mixed. A forced-action mixer is essential. Mixingin a suitably sized drum using an approved spiral paddle ina slow speed (400/500 rpm) heavy-duty drill is acceptablefor the occasional one-bag mix. Free-fall mixers must notbe used. Mixing of part bags should never be normal applications, place to litres of drinkingquality water into the mixer and, with the machine inoperation, add one full 20 kg bag of Renderoc hb40 andmix for 3 to 5 minutes until fully homogeneous.
9 Note thatthe powder must always be added to the strength:35 MPa @ 28 days(BS 6319 Pt 2: 1983 dry cure)Flexural MPa @ 28 days(BS 6319 Pt 3: 1990)Tensile MPa @ 28 days(BS 6319 Pt 7: 1985)Elastic modulus:18 kN/mm2 @ 28 days(BS 6319 Pt 6: 1984)Coefficient of thermalexpansion:11 x 10-6/ CFire rating:Non combustible (Class 0surface) (BS 476 Pt 4: 1970)The cured reinstatement mortar shall be shrinkagecompensated and highly impermeable to acid gases, waterand water-borne contaminants. It shall exhibit the shrinkage:< 400 microstrain at 7 daysASTM 23 C,RH50%ISAT:10 mins ml/m2/sec2 hours ml/m2/sec(BS 1881 Pt 5: 1970)Chloride diffusion:< 5 x 10-13 m2 s-1(Taywood bulk diffusion test, accelerated)Carbon dioxide barrier:600 mm (equivalentthickness of concrete to10 mm of Renderoc hb40 ,Taywood method)The mortar shall be capable of achieving the followingapplication thicknesses in a single by hand/trowel:40 mm30 mm by wet spraying:70 to 110 mm60 to 85 mmRenderoc hb40 manufactured by Parchem, meets instructionsPreparationSaw cut or cut back the extremities of the repair locations toa depth of at least 10 mm to avoid feather-edging and toprovide a square edge.
10 Break out the complete repair areato a minimum depth of 10 mm up to the sawn the surface and remove any dust, unsound orcontaminated material, plaster, oil, paint, grease, corrosiondeposits or algae. Where breaking out is not required,roughen the surface and remove any laitance by lightscabbling or steel reinforcing bars should be firmly secured toavoid movement during the application process as this willaffect mortar compaction, build and the mixed Renderoc hb40 to the prepared substrateby gloved hand or trowel. Thoroughly compact the mortaron to the primed substrate and around the exposedreinforcement. Renderoc hb40 can be applied in sectionsup to 40 mm thickness in vertical locations and up to 30mm thickness in overhead locations in a single applicationand without the use of formwork.