The Cement Express: Herbert Schulz delivers the raw materials for bridges and foundations

Herbert Schulz transports tens of thousands of kilos of the product day in, day out. But the driver only gets to see his load through a small pane of glass a few centimetres wide. When he unloads his silo trailer, he has to keep his eye on that. "I check if the cement's flowing smoothly," says 46-year-old Schulz on this winter afternoon.

The building material is pumped from the trailer through a thick black hose at one bar pressure. Two or three times, Herbert hits the aluminium wall with a rubber mallet to estimate the cement level by the echo. After almost three-quarters of an hour, about 29 tonnes of cement have flowed into the silo of the plant which manufactures ready-mixed concrete.

He almost always drives his Actros with the maximum load. "It's good to know I've got the latest safety technology on board!" Besides the Actros and Antos, Mercedes-Benz Trucks now offers Sideguard Assist for the Arocs construction site specialist. This means that the assistance system is now available in more than 20 vehicle versions. If moving or stationary obstacles as well as pedestrians or cyclists are located on the right-hand side of the vehicle in its warning area and if there is a risk of a collision, Sideguard Assist warns the driver both visually and acoustically. Safeguard Assist can also assist the driver when changing lanes to the right and thus also functions as a lane-change assistant at higher speeds.

Today, Herbert picked up his load at the Holcim cement works in Bremen. At his destination in Delmenhorst, gravel, sand, water and additional materials are added, before the fresh concrete is ready for immediate use.

It is very tricky transporting cement. This is particularly the case when ready-mixed concrete has to be made. The factories only produce when the construction sites have notified them of their requirements. And those needs can vary enormously. An important factor for this is the weather, because most sorts of ready-mixed concrete can neither be produced nor worked with at temperatures below freezing as the water in it will otherwise freeze.

Where ready-mixed concrete is involved, punctuality is crucial – which automatically applies to the cement transporter too. "If a motorway bridge is being built, for example, we normally work with so-called slipforming," explains Herbert. That means a fixed quantity of ready-mixed concrete must always flow into the casing. If the supply were held up, the workers would be forced to stop the process. The cement used until that point could harden. This would impair the stability of the construction.

Photos: Alexander Tempel, Christian Schmid
Video: Alexander Tempel