Recycling pavement with the iNOVA series

The CIBER iNOVA 1502 asphalt plant was used to process Reclaimed Asphalt Pavement (RAP) for a rehabilitation project on a major Brazilian road. CIBER Product Specialist Marcelo Zubaran explains the plant’s recycling capabilities.

The BR101 is the longest highway in Brazil. It runs close to 4,800 kilometres connecting major cities and towns. When a section of the BR101 needed upgrading near the tourist city in Natal, in Brazil’s north east, the contract with the National Department of Land Infrastructure was awarded to AGC Construções e Empreendimentos Ltda.

As a subcontractor Tecvia was tasked with producing an asphalt mix for the road. The Tecvia team had just 45 days to rehabilitate the road pavement and in that time, they produced 23,400 tonnes of asphalt mix.

To achieve this the Tecvica team used a CIBER iNOVA 1502 asphalt plant, which has a production capability of 150 tonnes per hour.

Despite the quick turnaround Tecvia decided to incorporate Reclaimed Asphalt Pavement (RAP) into their mix, with ranging levels of 12 to 18 per cent.

The iNOVA plant was equipped with a specialised RAP system, which allowed for the addition of RAP directly into the plant’s mixer.

CIBER Product and Application specialist, Marcelo Zubaran says the CIBER iNOVA Plants are available with an added feature for producing RAP asphalt mixes.

“The RAP option consists of a separate silo and a weighing system with a belt to transfer the dosage RAP to the pug mill mixer,” Mr. Zubaran says.

On the BR101 site the RAP materials were milled from the existing road using a Wirtgen W200 milling machine. The material was transported to the asphalt plant, which a short distance from the site. There it was screened within 24 hours and added to virgin materials to create the mix.

“There are no complications when using RAP in the iNOVA asphalt plants. You can keep the production rate high and just take out some of the raw materials to be replaced with the RAP. It doesn’t interfere in the production rate,” Mr. Zubaran says.

“Tecvia wanted to use RAP for two reasons, the first is to save costs, especially on virgin bitumen and the second is that they wanted to improve their ability to produce large amounts of RAP in asphalt mixes.”

Romero da Fonte, Director of Tecvia says during the project the virgin aggregates needed superheating to balance the cold and wet RAP as it entered the pug mill mixer.

The plant manages the burner flame intensity automatically to reach the target temperature of the virgin aggregates in the dryer and the final mix. The operator can select the final mix temperature and rely on the plant’s automation.

“The plant also managed the combustion gas temperature by automatically varying the speed of the dryer drum. Therefore, regardless of the virgin aggregates superheating, the bag house temperature remained perfect,” Mr. Fontes says.

Another feature of the plant which helps the production of RAP mixes is the automatic control of the mixing time. Mr. Fontes says when a cold and wet recycled material is added with hot aggregates and virgin bitumen, a great mixing force is required and a longer mixing time.

“With all this technology we achieved the perfect temperature and the perfect homogenisation of the mix and the plant worked in a steady state,” he says.

Mr. Fonte also says the compaction of the mix was excellent.

“After paving the mix, a specimen was taken to verify the grading and bitumen content and the results were perfectly achieved. It really overcame our expectations,” he says.

Mr. Zubaran says many customers are are demanding the technology to produce RAP.

“RAP is essential to producing asphalt mixes with increased sustainability because it is recycling the old pavement. It can save costs in production as the RAP contains old bitumen, which can reduce the amount of virgin bitumen needed to create an asphalt mix,” Mr. Zubaran says.

“I expect to see many more RAP projects using the iNOVA Asphalt plants and I am confident that more customers will demand this capability as they learn about the process of using RAP.”

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