Speed limits are down to 30mph on the stretch 24 hours a day where the works are being carried out with signage on the roadside stating that they are currently 48 percent complete.
Average speed checks are in place on the motorway and lanes have been narrowed while the work is carried out.
The scheme to replace the barriers began back in November last year, with Highways England saying at the time that they would take around six months.
Why do we need these concrete barriers on our roads?
In 2005, the government made the decision to phase out aging and dangerous steel barriers, replacing them with new concrete barriers.
The concrete versions are said to be much safer, with research suggesting that any vehicle up to 13.5 tons in weight will be contained, which covers most buses, 4x4s and coaches.
They are said to be designed to take some of the energy an impact causes and use this to move the impacting vehicle down the line of the barrier, therefore reducing the risk of a vehicle re-entering the carriageway, crossing over on to other lanes of traffic or flipping over.
They are also said to reduce the chance of motorists 'rubbernecking' incidents on the opposite carriageway, making for smoother traffic when there has been an accident.
What is the problem with the steel ones that are being replaced?
The steel versions that are being phased out were said to only be able to contain the weight of a Ford Focus, 1.5 ton.
The new concrete versions are said to last significantly longer than their steel counterparts and require less maintenance, meaning less lane closures in the suture.