Block D – Concrete Work

Trends

New materials used to construct forms are available to make them lighter and easier to use and to improve productivity and longevity. For example, aluminium, fibreglass and plastic forms are being used in commercial and residential applications. Use of insulated concrete forms (ICF) is becoming more popular because of its energy efficiency.

Concrete is increasingly used for aesthetic applications such as countertops and signage.

Related Components (including, but not limited to)

Formwork: shoring, shoring hardware, bracing, mud sills, strongbacks, turnbuckles, walers, clamps, wedges, ties, clips, embeds.

Concrete, grout, epoxies, caulking, admixtures (plasticizers, accelerators, colours, hardeners), bonding agents, acids, polyethylene, burlap, curing compounds, sealers, form release agents.

Tools and Equipment

See Appendix A.

Task 12 Forms concrete.

Context

Concrete forms are the beginning structure in most construction projects. They are used for architectural and structural applications. They hold and support concrete until it is set.

Required Knowledge

• K 1 types of shoring such as fixed, telescoping and scaffold
• K 2 shoring hardware such as anchor pins, spring clips and base plates
• K 3 shoring ratings and regulations
• K 4 spacing of shoring
• K 5 types of forms such as steel, handset (loose), fly table, fly form and void (for openings)
• K 6 formwork components such as bracing, shoring, falsework, strongbacks, turnbuckles, walers, clamps, wedges, ties and clips
• K 7 ratings and applications of types of formwork
• K 8 materials used to create forms
• K 9 locations requiring inspection such as steps, bulkheads and corners
• K 10 dismantling procedures and sequences

Sub-task D-12.01 Installs formwork and shoring.

Key Competencies

• D-12.01.01 select and use tools and equipment such as measuring tapes, hammers, levels, plumb bobs and saws
• D-12.01.02 verify location and size of concrete structure such as walls, slabs and columns to be poured according to job specifications
• D-12.01.03 verify formwork system to be used such as wooden panels, pre-fabricated, free-form, metal fabricated and ICF
• D-12.01.04 determine installation procedures and materials required according to job and manufacturers’ specifications
• D-12.01.05 assemble and fasten formwork components according to manufacturers’ or engineering specifications
• D-12.01.06 recognize and correct defects in formwork such as misalignment and spacing
• D-12.01.07 modify formwork to accommodate design alterations
• D-12.01.08 apply form release agents to prevent damage and for ease of releasing formwork
• D-12.01.09 install shoring and bracing according to specifications to support concrete structures
• D-12.01.10 secure shoring near slab edge
• D-12.01.11 adjust shoring as required according to engineering specifications
• D-12.01.12 plumb and straighten walls using bracing and turnbuckles

Sub-task D-12.02 Inspects assembled formwork.

Key Competencies

• D-12.02.01 select and use measuring tools such as measuring tapes and levels
• D-12.02.02 recognize defects in formwork such as misalignment and spacing
• D-12.02.03 verify elevations and layout such as location of rough bucks (door openings), window block outs and beam pockets
• D-12.02.04 check all shoring and bracing to ensure formwork is secure, plumb and stable according to job specifications

Sub-task D-12.03 Dismantles formwork.

Key Competencies

• D-12.03.01 prepare plan for dismantling formwork considering factors such as starting point, sequence and placement of material
• D-12.03.02 select and use tools and equipment such as pry bars, wrenches and hammers
• D-12.03.03 remove fasteners such as nails, bolts and formwork components while ensuring formwork does not fall by leaving some ties in place
• D-12.03.04 stack components for reuse or transport

Sub-task D-12.04 Maintains formwork.

Key Competencies

• D-12.04.01 inspect disassembled formwork components for deficiencies and damage
• D-12.04.02 select and use tools and equipment such as grinders for metal formwork, rollers and sprayers
• D-12.04.03 scrape and clean formwork components
• D-12.04.04 apply form release agents or materials
• D-12.04.05 grease taper ties to facilitate ease of removal
• D-12.04.06 place formwork in designated lay down area

Task 13 Places and finishes concrete.

Context

Proper mixing of concrete is very important to ensure the desired strength and consistency. Concrete needs to be transported for installation using methods such as concrete pumps, line pumps and cranes. Placing of the concrete includes pouring, vibrating to eliminate voids and establishing a rough-grade. It is then finished to achieve the final grade and appearance. Concrete cures by holding moisture; it is important to keep concrete hydrated during this curing process to avoid shrinkage and cracking.

Required Knowledge

• K 1 types of concrete and their uses such as air entrained, shotcrete and high flow
• K 2 strengths of concrete and slump
• K 3 concrete aggregates
• K 4 concrete additives such as plasticizers, accelerators and retarders
• K 5 access and egress considerations
• K 6 components such as dowels, safety lines, key ways, anchor bolts and steel plates
• K 7 component installation methods for freshly placed concrete such as wet dowelling and installing anchor bolts
• K 8 cured concrete component installation methods such as drilling, chipping and saw cuts
• K 9 pour rates
• K 10 concrete transportation and placing equipment such as line pumps and boom pumps
• K 11 height from which concrete may be placed
• K 12 surface preparation requirements
• K 13 types of finishes such as hard float, broomed, polished, exposed aggregate and burn finish
• K 14 finishing processes such as floating, trowelling and edging
• K 15 timing for finishing processes
• K 16 weather and environmental conditions such as heat, cold, exhaust fumes and dust that may affect the curing process
• K 17 rate of curing time
• K 18 PPE and safety equipment

Sub-task D-13.01 Mixes concrete.

Key Competencies

• D-13.01.01 select and use tools and equipment such as mixers, drills, mixing paddles, pails and trowels
• D-13.01.02 select materials such as aggregates, water and cement
• D-13.01.03 mix according to work schedule and weather conditions
• D-13.01.04 use additives such as pigments, accelerators and retarders according to specifications
• D-13.01.05 combine ingredients according to predetermined instructions such as ratios, mixing times and compatibilities

Sub-task D-13.02 Transports concrete on site.

Key Competencies

• D-13.02.01 plan placement of the concrete truck
• D-13.02.02 plan route from truck to site of placement to avoid obstacles and to allow for ease of access
• D-13.02.03 select, position and use transporting equipment such as wheelbarrows, concrete pumps, power buggies, concrete buckets and skidsteers
• D-13.02.04 monitor and communicate the rate of pour

Sub-task D-13.03 Places concrete.

Key Competencies

• D-13.03.01 select and use tools and equipment such as concrete vibrators, stationary pumps, rakes, shovels and screeding tools
• D-13.03.02 plan the sequence of placement
• D-13.03.03 monitor and communicate the rate of pour
• D-13.03.04 vibrate, spread and screed floor slabs to desired height or level
• D-13.03.05 place and vibrate wall to desired height
• D-13.03.06 ensure level pour with methods such as wet screeding, using tools and equipment such as height sticks, laser levels and grade nails
• D-13.03.07 recognize and rectify surface irregularities such as dips, high spots and holes

Sub-task D-13.04 Installs components in concrete.

Key Competencies

• D-13.04.01 select and use tools and equipment such as measuring tapes, string lines, hammers, levels and drills
• D-13.04.02 measure, lay out and position components such as anchor plates, anchor bolts, water stops, control joints, key ways and reinforcing material, according to specifications

Sub-task D-13.05 Assists with finishing concrete.

Key Competencies

• D-13.05.01 select and use finishing tools and equipment such as floats, hand trowels, power trowels, edgers and brooms
• D-13.05.02 work concrete at different stages of setting with various finishing tools to reach desired finish according to job specifications

Sub-task D-13.06 Controls concrete curing process.

Key Competencies

• D-13.06.01 hydrate concrete using materials and equipment such as burlap, polyethylene, soaker hoses and sprinklers to control curing process according to specifications and weather conditions
• D-13.06.02 trap moisture in concrete to avoid evaporation using curing compounds
• D-13.06.03 prevent heat loss and freezing in cold weather by using insulated tarps or heaters
• D-13.06.04 use squeegees, power vac and other methods to control bleed water

Task 14 Modifies concrete.

Context

Concrete may be modified after it has been installed. These tasks may be done to create openings, maintain structural integrity, control expansion and contraction or simply for aesthetic reasons.

Required Knowledge

• K 1 wet and dry drilling/coring procedures
• K 2 types and properties of concrete to be drilled/cored
• K 3 reasons for drilling/coring concrete such as adding components, running sleeves, fastening items and demolition
• K 4 embedded items such as water lines, electrical conduit and rebar
• K 5 products and chemical agents used for repair and refinishing such as bonding agents, epoxies, grout, patching materials and acids
• K 6 deficiencies in concrete that can be repaired
• K 7 finishing requirements
• K 8 reasons for installing concrete joints
• K 9 types of joints such as expansion, control and isolation
• K 10 depth and spacing of joints
• K 11 types of cuts such as green cuts, wet cuts and dry cuts
• K 12 refinishing methods such as painting, epoxy coating, parging, acid staining and acid etching
• K 13 PPE and safety equipment

Sub-task D-14.01 Drills/cores concrete.

Key Competencies

• D-14.01.01 select tools and equipment such as core and rotary hammer drills and their bits
• D-14.01.02 lay out and mark hole according to specifications
• D-14.01.03 verify embedded items in concrete such as post tension cables, rebar and conduit by x-ray or blueprints
• D-14.01.04 anchor base of core drill
• D-14.01.05 listen and feel for obstructions during drilling process
• D-14.01.06 control speed, pressure and water flow during drilling process
• D-14.01.07 control dust using water and/or by tarping, ventilating and vacuuming
• D-14.01.08 control slurry while drilling by using methods such as damming and vacuuming

Sub-task D-14.02 Prepares concrete for resurfacing.

Key Competencies

• D-14.02.01 select and use tools and equipment such as PPE, bush hammers, scarifiers and floor grinders
• D-14.02.02 mechanically remove finish using methods such as chipping, bush hammering, media blasting and scarifying
• D-14.02.03 chemically remove finish using acids
• D-14.02.04 clean surface by vacuuming, blowing, sandblasting or washing

Sub-task D-14.03 Performs concrete repair and refinishing.

Key Competencies

• D-14.03.01 select tools and equipment such as trowels, sponges, grinders, sanders, brushes, brooms and chipping guns
• D-14.03.02 apply bonding agents according to job specifications
• D-14.03.03 apply materials according to job specifications to repair honeycombs, voids and other deficiencies to achieve desired finishes

Sub-task D-14.04 Creates expansion, control and isolation joints.

Key Competencies

• D-14.04.01 select and use tools and equipment such as saws and groovers (two-sided edgers, dividers)
• D-14.04.02 select materials such as dowels according to type of joint and job specifications
• D-14.04.03 control cracking by cutting concrete, installing plastic strips or installing sill gaskets, according to engineering specifications

Task 15 Places/Applies grout, epoxies and caulking.

Context

Grout and epoxies provide structural integrity. Caulking is used to seal against leaks and for an aesthetic finish.

Required Knowledge

• K 1 types of grout products and their applications
• K 2 types of epoxies such as liquid and paste
• K 3 hazards and precautions to be considered when working with epoxies
• K 4 types of caulking such as firestop, exterior and interior
• K 5 manufacturers' specifications
• K 6 time constraints and product properties
• K 7 PPE and SDS

Sub-task D-15.01 Places/Applies grout.

Key Competencies

• D-15.01.01 select and use tools and equipment for grouting such as mixing paddles, trowels, shovels, drills, funnels, sponges and brushes
• D-15.01.02 mix grout according to engineering and manufacturers’ specifications
• D-15.01.03 grout components such as door frames, anchor bolts, machine bases, walls, beams and columns using dry packing or pouring method
• D-15.01.04 trowel and shape grout to a smooth finish for aesthetic purposes

Sub-task D-15.02 Places/Applies epoxies.

Key Competencies

• D-15.02.01 pre-plan for work considering time constraints of applying epoxies
• D-15.02.02 prepare surfaces using cleaning equipment
• D-15.02.03 mix epoxies according to manufacturers’ specifications
• D-15.02.04 apply epoxies using epoxy guns, or placing and spreading according to job specifications

Sub-task D-15.03 Applies caulking.

Key Competencies

• D-15.03.01 select and use tools and equipment such as caulking guns and cleaning equipment
• D-15.03.02 clean exposed surfaces using methods such as applying solvents, pressure washing and sandblasting according to job specifications
• D-15.03.03 use fillers such as insulation and backing rod
• D-15.03.04 apply a steady bead and ensure voids are filled by tooling caulking