Part E - Standard Construction Procedures And Equipment
The information contained below is intended to be a guide for inspectors, providing supplemental and supporting information for the requirements in the Standard Specifications. This information is not a Contract Document.
This is further supplemented by AASHTO Training Courses, available at https://transportation.org or on the Delaware Learning Center for state employees.
Earthwork is the process of moving, shaping, and compacting soil and rock to build the foundation for a road, bridge, or other transportation project. This includes:
- Clearing and grubbing – Removing trees, vegetation, and debris from the site.
- Excavation (cut) – Digging out material where the ground is too high.
- Embankment (fill) – Adding and compacting material where the ground is too low.
- Grading – Shaping the ground to the correct elevations and slopes per plan.
- Compaction – Densifying the soil in lifts to meet spec requirements (typically tested by a nuclear density gauge or other approved method).
- Borrow and waste – Hauling in material from off-site when there's not enough on-site fill, or disposing of excess material when there's too much.
For DelDOT crews, earthwork is essentially getting the subgrade to the right grade, alignment, and density before pavement structure or structure work begins — it's the backbone of every project.
Please visit the DIVISION E2.00 page for additional information.
Base Course is the layer (or layers) of compacted material placed on top of the prepared subgrade that provides a stable, load-bearing foundation for the pavement surface above it.
Common Base Course Types in DelDOT's 300 Section:
- Subbase Course – The lower base layer, typically a granular material like gravel, placed directly on the subgrade to improve drainage and load distribution.
- Graded Aggregate Base Course – Compacted crushed stone that provides a strong, stable platform; gradation and compaction must meet DelDOT spec.
- Treated Base – Aggregate mixed with a binder to create a more rigid, stabilized base layer.
Key Concepts for DelDOT Construction Staff:
- Lifts – Base material is placed and compacted in specified layer thicknesses; never dump and compact the full depth at once.
- Compaction testing – Density must be verified per spec, typically by nuclear gauge or other approved method.
- Proof rolling – A loaded tandem truck or roller is run across the base to identify soft spots before paving.
- Grade and cross-slope – Base course must be shaped to the correct elevations and crown so water drains off and doesn't pond under the pavement.
- Contamination – Keeping base material free of subgrade mixing or organic material is critical to long-term pavement performance.
For DelDOT crews, a properly constructed base course is what keeps the finished pavement from cracking, rutting, or failing prematurely — getting it right here saves costly repairs down the road.
Please visit the DIVISION E3.00 page for additional information.
Bituminous Materials refers to asphalt-based paving mixtures and treatments that are placed on top of the base course to create a durable, smooth, and weather-resistant driving surface.
Key Concepts for DelDOT Construction Staff:
- Mix Temperature – Material must be placed and compacted within a specified temperature window; material that is too cold will not compact properly and will fail prematurely.
- Compaction – Rollers must achieve the required density before the mat cools; this is one of the most time-sensitive operations in paving.
- Lift Thickness – Each layer must be placed at the correct thickness per plan; too thin and the mix won't compact properly, too thick and you won't achieve density through the full depth.
- Longitudinal and Transverse Joints – Seams between paving passes are common failure points; proper joint construction and compaction is essential.
- Smoothness/Rideability – DelDOT uses profilograph or IRI (International Roughness Index) measurements to evaluate finished pavement smoothness; poor smoothness can result in pay adjustments.
- Tack Coat Coverage – Proper application rate and coverage between all lifts ensures the pavement system bonds and acts as one unit rather than slipping apart under traffic.
- Haul Time and Trucking – Material that sits too long in the truck loses heat and workability; coordination between the plant and paving crew is critical.
**NEW** Tack Coat Emulsion Sampling Procedure for Construction Inspectors.
For DelDOT crews, bituminous work is often the most visible part of a project — it's what the public sees and drives on every day. Getting the temperature, compaction, and smoothness right is what separates a pavement that lasts 20 years from one that needs patching in five.
Please visit the DIVISION E4.00 page for additional information.
Rigid Pavement refers to concrete pavement systems that derive their strength from the stiffness of the concrete slab itself, rather than relying on the layers beneath it to distribute load like flexible (bituminous) pavement does. The term "rigid" comes from the fact that concrete does not flex or deflect significantly under traffic loads — it spreads the load over a wide area before transferring it to the base and subgrade below.
Key Structural Components:
- Subbase – The prepared layer beneath the concrete slab; provides uniform support, drainage, and prevents pumping of fine material through joints.
- Dowel Bars – Smooth steel bars placed at transverse joints to transfer load between slabs while allowing horizontal movement.
- Tie Bars – Deformed steel bars placed at longitudinal joints to hold adjacent slabs together and prevent lanes from separating.
- Joint Sealant – Material placed in saw-cut joints to prevent water and incompressibles (dirt, stone) from infiltrating and causing damage.
Key Concepts for DelDOT Construction Staff:
- Concrete Mix Design – The mix must meet DelDOT's specified strength (typically measured by flexural strength or modulus of rupture), workability, and durability requirements.
- Subgrade and Subbase Preparation – Concrete is unforgiving; any soft spots, irregularities, or inadequate support beneath the slab will reflect as cracking or settlement over time — proof rolling is critical before placement.
- Forming and Grade Control – Slipform pavers use stringline or 3D grade control to maintain precise slab thickness, width, and cross-slope; fixed form paving requires careful form setting.
- Consolidation – Internal and perimeter vibrators must be used properly to eliminate voids and honeycombing without over-vibrating, which can cause segregation.
- Jointing – Transverse joints must be saw-cut within a tight time window after placement; cut too early and you ravel the surface, cut too late and uncontrolled random cracking occurs.
- Curing – Concrete must be cured immediately after finishing using white-pigmented curing compound or wet curing methods; loss of moisture too early causes surface shrinkage cracking and reduces long-term strength.
- Opening to Traffic – Concrete must reach the specified minimum strength before opening to traffic; opening too early causes damage that cannot be undone.
- Concrete Pavement Restoration – On existing rigid pavement projects, crews may perform diamond grinding, joint resealing, dowel bar retrofit, or slab replacement rather than full reconstruction.
For DelDOT crews, rigid pavement requires a higher level of precision and timing than asphalt work — from subbase prep through jointing and curing, every step has a narrow window to get it right. Done correctly, a concrete pavement will outlast almost any other surface type and require minimal maintenance for decades.
Please visit the DIVISION E5.00 page for additional information.
Structures covers the construction, rehabilitation, and maintenance of bridges, culverts, retaining walls, and other engineered structures that carry traffic, manage drainage, or support the roadway system.
Where earthwork and pavement build the road surface, structures carry that road over obstacles — rivers, other roads, railroads, and valleys — or hold the earth in place where the terrain would otherwise make construction impossible.
Work Covered Under This Section:
- Bridges (beam, box beam, slab, and truss types)
- Culverts (reinforced concrete pipe, box culverts, metal pipe and arch)
- Retaining walls (MSE walls, cast-in-place concrete, sheet pile)
- Approach slabs, headwalls, and endwalls
- Noise walls and overhead sign structures
Key Things to Watch in the Field
- Falsework and Formwork
- Temporary support structures must be properly designed and inspected before any concrete is placed — falsework failures are among the most serious events in bridge construction.
- Reinforcing Steel Placement
- Rebar cover, spacing, lap lengths, and tying must match the plan exactly. Errors are hidden once concrete is placed and lead to premature deterioration.
- Concrete Placement and Curing
- Bridge decks are highly vulnerable to shrinkage cracking. Control mix temperature, placement sequence, finishing, and curing duration per spec — do not cut corners here.
- Bearing and Joint Installation
- Bearings and expansion joints must be set at the correct elevation and gap width for the temperature at time of installation. Getting this wrong causes long-term problems that are expensive to fix.
- Scour Monitoring
- Erosion around bridge foundations during flood events is the leading cause of bridge failures nationally. Monitor scour-critical structures during and after high water events and report concerns immediately.
- Load Ratings
- Never stage heavy equipment or stockpile material on a bridge deck without confirming the structure's load rating. Coordinate with the Engineer before any overweight loads cross the structure.
For DelDOT crews, structures work demands the highest level of coordination between the field and the Engineer. Unlike pavement, where minor deficiencies can often be addressed through maintenance, structural defects are difficult and expensive to correct once the concrete is placed — getting it right the first time is not optional.
Please visit the DIVISION E6.00 page for additional information.
Miscellaneous Construction covers the wide variety of ancillary work items that don't fit neatly into earthwork, paving, or structures but are essential to delivering a complete, functional, and safe roadway. This includes items such as guardrail, fencing, curb and gutter, and sidewalks. Though sometimes treated as afterthoughts, 700 section items are frequently high-visibility to the public and subject to close scrutiny from inspectors, property owners, and regulatory agencies alike.
Key Things to Watch in the Field
- Guardrail
- Post spacing, blockout depth, end treatments, and anchorage must match the plan and DelDOT spec exactly — guardrail that isn't installed correctly can fail to redirect an errant vehicle as designed.
- ADA Compliance
- Curb ramps, detectable warning surfaces, and sidewalk grades are subject to ADA requirements. These are closely inspected and costly to correct after the fact if not built right the first time.
- Curb and Gutter
- Check line and grade, joint spacing, and mix placement. Curb that doesn't drain properly or doesn't match plan alignment will pond water against the pavement and accelerate deterioration.
- Sidewalk
- Verify thickness, subgrade preparation, joint layout, and cross-slope. Sidewalk panels that settle or exceed allowable cross-slope become ADA and pedestrian safety issues.
For DelDOT crews, miscellaneous items are often the last things built on a project — but they are the first things the public notices. A crooked guardrail run, a curb ramp that doesn't meet grade, or a sidewalk panel that settles will draw complaints long after the paving crew has moved on.
Please visit the DIVISION E7.00 page for additional information.
Division 800 covers all temporary traffic control measures required to safely maintain the movement of vehicles, pedestrians, and cyclists through and around an active construction zone. This includes everything from the Traffic Control Plan itself to the physical devices used to guide and protect the traveling public — arrow boards, portable changeable message signs, drums, cones, temporary barrier, attenuators, flaggers, traffic officers, and the supervisory requirements that govern them all. Unlike most other divisions, the work here is actively managed, inspected, and adjusted throughout the life of the project.
Key Things to Watch in the Field:
- Traffic Control Plan (TCP) Compliance
- All lane closures, detours, and device placements must match the approved TCP. Deviations — even well-intentioned ones — must be coordinated with the Engineer first.
- MASH Compliance
- The 2026 spec requires temporary devices (barrier, attenuators, drums, etc.) to meet MASH 2016 crash test standards. Verify that equipment on-site appears on DelDOT's approved MASH device list and the project Source of Supply before it goes into service.
- Flaggers
- Flaggers must be trained and certified. Observe their positioning, visibility, and communication with one another — a poorly positioned flagger creates a hazardous condition for both workers and drivers.
- Temporary Safety Barrier and Attenuators
- Barrier must be properly placed, connected, and (if required) pinned. Do not allow work to occur within the barrier's deflection area.
- Truck Mounted Attenuators (TMAs) and Temporary Impact Attenuators must be in place whenever crews are working in or adjacent to live traffic — do not allow work to begin without them.
- Device Condition and Placement
- Walk the work zone daily. Drums, cones, and signs that are knocked over, faded, or missing retroreflective sheeting must be corrected immediately. A poorly maintained work zone is one of the most visible indicators of contractor performance to the public.
**NEW!** Interim Guidance - Detours and Lane Closures on Interstates, Freeways, and Expressways - 2025
For DelDOT crews, traffic control is the one part of every project that is never "done" — it requires daily attention from the first cone placed to the last device removed. A well-maintained work zone protects both the traveling public and the crew, and it reflects directly on DelDOT's reputation with every driver who passes through it.
Please visit the DIVISION E8.00 page for additional information.
Division 900 covers all measures required to control erosion, capture sediment, and manage stormwater runoff generated by land-disturbing construction activities. This includes the installation and maintenance of perimeter controls, inlet protection, sediment traps and basins, dewatering operations, stabilization practices, and permanent stormwater management facilities. Unlike most construction work, E&S compliance is not a one-time installation — it is an active, daily responsibility that runs from the first ground disturbance through final site stabilization and project closeout. Non-compliance carries real consequences: DelDOT operates under delegation from DNREC and is a co-permittee under the NPDES Construction General Permit, which was reauthorized effective March 11, 2026. Violations can result in regulatory fines, stop-work orders, and permit jeopardy for the entire project.
Key Things to Watch in the Field:
- Blue Card / Responsible Person
- Before any land-disturbing activity begins, the contractor must have a DNREC-certified Responsible Person (Blue Card holder) on site. Confirm credentials at the preconstruction meeting and verify they remain current throughout the project — this is a permit requirement, not just a spec requirement.
- Perimeter Controls First
- Silt fence, compost filter logs, and other perimeter controls must be installed and inspected before clearing begins. Controls installed after the fact are a violation. Sequence matters.
- If clearing is necessary to install perimeter controls, the Contractor should only clear enough to make the installation. They are not permitted to continue clearing other areas until perimeter controls are installed.
- Silt fence, compost filter logs, and other perimeter controls must be installed and inspected before clearing begins. Controls installed after the fact are a violation. Sequence matters.
- Inlet Protection
- Every storm drain inlet within and adjacent to the project must be protected. Knocked-over or clogged inlet protection devices are among the most common deficiencies cited during regulatory inspections.
- Dewatering Operations
- Pumped or discharged water from excavations and basins must be treated before it leaves the site. Discharging turbid water directly to a storm drain, ditch, or waterway is a violation.
- Final Stabilization
- E&S measures cannot be removed, and permit coverage cannot be closed until all disturbed areas have achieved final stabilization — typically defined as 70% perennial vegetative cover. Do not allow the contractor to remove controls prematurely.
For DelDOT crews, erosion and sediment control is the one responsibility that never takes a day off — it applies before, during, and after every other activity on the project. A missed silt fence repair or uncovered inlet can trigger a regulatory inspection that affects the entire project schedule. Staying ahead of E&S is not extra work; it is the work.
Please visit the DIVISION E9.00 page for additional information.