Dry Laid retaining Wall Systems by Anderton Concrete
During the CPD, a representative of Anderton Concrete presented two retaining wall systems which utilize dry laid blocks; namely Keystone and Slopeloc.
The wall systems comprise concrete blocks which are designed to interlock, allowing them to connect together in modular fashion to form vertical walls without requiring mortar. The resulting wall has the strength to withstand lateral loading on one side, with void space and therefore unsupported on the other. Of the two types presented, the Keystone system forms a vertical wall whereas the Slopeloc system forms a sloping wall.
There are benefits to the wall systems being laid dry as opposed to other systems such as Stepoc or hollow block which require liquid cement to be poured through the central cavities of the blocks once in place.
In terms of their sustainability, the dry wall systems minimise concrete production and therefore carbon emissions. According to think tank Chatham House, cement is estimated to be the source of 8% of the world's CO2 emissions. Being dry laid, the blocks may also be reused in a new arrangement or location.
Other benefits are in terms of construction convenience. The walls may be laid in all weather conditions which maximises construction speed, and being dry laid minimises personnel required on site and improves site safety. Once constructed, maintenace of the walls is also minimised due to the absence of mortar. The systems are ideally suited to railway tunnels and bridges, and as a further benefit, being dry laid minimises disturbance to surrounding terrain which allows infrastructire to remain operational during wall constuction.
Height performance is uncompromised when the wall systems are used in conjunction with a geogrid. The systems are specially designed for connection with a geogrid and when utilised, construction heights of over 15 meters can be achieved. A geogrid is a geosyntheic material used to reinforce the tension capacity of soils and smilar geological material which have inherent low tensile strength and therefore low stability. The use of a geogrid in combination with specially designed high strength connections of the blocks enables the walls to accommodate high surcharge as well as being built high.
In conclusion, dry laid retaining wall systems offer a faster, higher quality solution for laying retaining walls with less disturbance to surrounding terrain and infrastructure. They also offer a more sustainable solution due to minimising concrete production as well as the ability to reuse blocks in a new arrangement or location.