Cold In-Place Asphalt Recycling in Dense Urban Settings: Beverly Hills Road Repair Strategies

When major road infrastructure requires rehabilitation in dense urban settings, contractors face a difficult balance between comprehensive pavement repair and maintaining mobility for residents and commuters. The Cold in Place Asphalt Recycling On Californias I approach has emerged as a proven solution for urban environments where traffic disruption must be minimised. Nowhere was this demonstrated more effectively than in the City of Beverly Hills, where a crew of 20 employees from Pavement Recycling Systems and Sully Miller Contracting repaired and repaved 1.3 million square feet of roads in just eight days during August 2010. This article examines the cold in-place recycling process through the lens of that project and provides actionable strategies for contractors considering CIR for urban road rehabilitation.

Understanding Cold In-Place Asphalt Recycling

Cold in-place asphalt recycling (CIR) is a pavement rehabilitation method that mills existing asphalt, processes it on site, and reuses it as a base course for new pavement. Unlike traditional hot mix methods that require hauling material to and from an asphalt plant, CIR completes the entire operation on the jobsite using a coordinated train of equipment. As James Emerson of Pavement Recycling Systems explained in the original For Construction Pros report, cold in-place asphalt recycling takes existing asphalt and reuses it on site at a substantially reduced cost compared to traditional mill and fill operations.

How CIR Differs from Hot Recycling

The fundamental distinction between CIR and hot recycling lies in temperature and processing location. Hot recycling requires transporting milled asphalt to a central plant, where it is heated, mixed with new binder, and brought back to the jobsite. CIR eliminates both trips by processing material at the point of milling. This distinction carries significant implications for project timelines, traffic management, and overall cost.

The Equipment Train

The CIR process relies on a coordinated sequence of equipment often referred to as the recycling train. On the Beverly Hills project, the train consisted of the following components:

1. A 12.5-foot-wide cold planing milling machine that cut the existing pavement to a depth of 3 inches
2. A 100% closed circuit portable recycle plant towed behind the front mill, where milled asphalt was crushed and screened until 1-inch material passed
3. A weigh bridge on the plant that measured the processed material
4. A pug mill where the crushed asphalt was blended with engineered emulsion
5. A material transfer vehicle that collected the recycled mix
6. A paving unit as the final element, which laid the recycled base course

This train configuration allowed both the milling-recycling operation and the paving crew to work simultaneously on the same site, eliminating the sequential delays common in traditional reconstruction projects.

Traffic Management Strategies for Urban CIR Projects

One of the most challenging aspects of urban road rehabilitation is maintaining traffic flow during construction. According to Marco Estrada, P.E. of Pavement Recycling Systems, the City of Beverly Hills required that one lane of traffic remain open in both directions at all times. This constraint shaped every aspect of the construction plan and offers valuable lessons for contractors working in similarly dense environments.

Lane Phasing and Sequencing

CIR offers advantages for lane phasing because the train can work efficiently within a single lane width. On the Beverly Hills project, crews worked on outside lanes while keeping inside lanes open, then switched to inside lanes while outside lanes carried traffic. This approach meant that at no point during the eight-day project was any road completely closed in both directions.

Key traffic management strategies for urban CIR include:

• Phasing lane closures so that residential and emergency access is maintained on each block
• Coordinating with local traffic authorities to adjust signal timing during construction hours
• Using overnight or off-peak working windows where full closures become feasible
• Posting advance notice signage at least 48 hours before lane restrictions begin
• Maintaining separate access routes for garbage collection, deliveries, and emergency vehicles

Reducing Off-Site Traffic Impact

Beyond lane management, CIR reduces off-site traffic impact by eliminating thousands of haul truck trips. Emerson estimated that the Beverly Hills project eliminated 2,800 trucks from local roadways. Each eliminated truck trip represents reduced congestion, lower emissions, and fewer disruptions for residents. For urban projects where public tolerance for construction traffic is low, this benefit alone can justify the CIR approach.

Materials, Binders, and Quality Control in CIR

The success of any cold in-place recycling project depends heavily on material selection and quality control during processing. The existing asphalt being recycled is old and dry. Without proper treatment, it lacks the binding characteristics needed for a durable base course. The emulsion added during the CIR process serves dual functions as both a binder and a rejuvenator for the aged asphalt.

Emulsion Selection and Application

On the Beverly Hills project, crews used Western Emulsion Pass-R engineered emulsion. According to Estrada, the recycled asphalt is old and dry, and the emulsion softens the existing asphalt while binding everything together. The emulsion is added in the pug mill after the recycled material has been crushed, screened, and weighed, ensuring precise dosage control.

Factors to consider when selecting an emulsion for CIR include:

• The age and oxidation level of the existing pavement, which determines how much rejuvenation is needed
• Traffic loads on the finished road, which influence the required binder performance grade
• Ambient temperature during construction, which affects emulsion cure time
• Moisture content of the milled material, which impacts emulsion adhesion
• Compatibility between the emulsion chemistry and the aggregate type in the existing mix

Quality Control During Processing

The closed circuit recycle plant used on the Beverly Hills project ensured that material gradation was tightly controlled. The plant crushed and screened the milled asphalt until all material passed through a 1-inch screen. This consistent gradation is essential for achieving uniform compaction and structural performance in the recycled base course. The weigh bridge on the plant allowed operators to measure material flow and adjust emulsion dosage in real time, maintaining consistent mix properties throughout the project.

For contractors setting up their own CIR quality control program, the following checks are recommended:

1. Perform a pavement coring survey before milling to determine existing pavement thickness and condition
2. Conduct laboratory mix design on representative samples to establish the target emulsion content
3. Monitor gradation continuously during crushing and screening operations
4. Verify emulsion application rate through daily calibration checks on the pug mill
5. Test compacted density on the finished base course using nuclear gauge or core samples

Cost, Scheduling, and Performance Benefits of CIR

The Beverly Hills project demonstrated cold in-place recycling as a compelling value proposition for urban pavement rehabilitation. The combination of cost savings, schedule compression, and long-term performance makes CIR an attractive option for municipalities and contractors alike.

Quantified Cost Advantages

Emerson estimated a total of 42% cost savings for the Beverly Hills CIR project compared to traditional mill and fill. These savings come from multiple sources: the elimination of trucking costs to and from the asphalt plant, reduced virgin material requirements, shorter construction duration, and lower equipment mobilisation costs. For taxpayers funding municipal road projects, a 42% reduction represents a substantial saving that can extend a road budget to cover more lane-miles of rehabilitation.

Schedule Compression

By having the milling-recycling operation and the paving crew on site simultaneously, the project saw a reduction in construction time by one-third, according to Emerson. The 20-person crew from both Pavement Recycling Systems and Sully Miller Contracting completed 1.3 million square feet of road rehabilitation in only eight days. In an urban environment where every day of construction causes economic disruption for local businesses and inconvenience for residents, this schedule advantage carries real value beyond the direct cost savings.

Long-Term Pavement Performance

Beyond the immediate cost and schedule benefits, CIR produces a pavement structure with distinct performance characteristics. The recycled base course creates a tighter surface with less loose gravel on the road compared to some traditional methods. Furthermore, as Emerson noted, the ability to continually recycle asphalt every 20 years means one pavement system no longer has to have only one lifespan. Each CIR cycle extends the service life of the pavement structure, creating a sustainable cycle of rehabilitation that reduces long-term material consumption.

For contractors and agencies evaluating CIR for their own projects, the proven benefits include reduced material costs, shorter road closure durations, lower community disruption, and a more sustainable pavement life cycle. The Asphalt Pavement Recycling Technologies Methods and Sustainable Practices used in projects like the Beverly Hills rehabilitation continue to evolve, offering ever-improving performance for cold recycling applications.

Contractors considering CIR should also evaluate Asphalt Safety Comprehensive Guide to Hazard Management in hot mix operations, as cold in-place recycling presents different safety considerations compared to traditional hot mix work. Understanding the full range of Asphalt Plants and Pavement Construction Equipment a Complete options available helps contractors select the right approach for each unique project circumstance.