Fourth-year Civil Engineering students have a course about maintenance and paving technology integrated with English language studies. One part of the course is to make various tests at the school’s accredited pavement laboratory. In this article two of the students describe the experience in the laboratory, and also talk about the course in general. The idea of the laboratory experiments is to teach how to make asphalt and to test the qualities of the components included in asphalt, and then afterwards to report about the tests in English. This article will give you a general idea what the pavement laboratory is, and two of the tests made during the laboratory sessions will be described in more detail.

At the pavement laboratory of Oulu University of Applied Sciences, it is possible to perform research and sampling of asphalt and aggregates. The laboratory has a PANK-certificate. The PANK-certificate is an approval procedure for asphalt, bitumen and aggregate laboratories [1]. The laboratory has many different types of equipment and because you need to handle dusty and hot materials, it is important to use the right kind of protective equipment. The protective equipment includes safety shoes, lab coat, protective glasses, and gloves. Working in the laboratory is not dangerous if you follow the instructions.

During the laboratory experiment, several tests were made from preparing the materials to making an asphalt sample. All the tests were made according to different European Standards that are approved by CEN (European Committee for Standardization). These standards also have the status of a Finnish national standard (SFS Ry) [2]. Next, we will explain the two most interesting tests in our opinion. These two tests were the most interesting and fun to do because there were a lot of parts that we could do by hand ourselves.

Asphalt plays an important role in our daily activities. We use asphalt roads all the time – but do we only notice them when they are of bad quality?

Bitumen

When making asphalt you need aggregates, a binder and filler. The binder used in our tests was bitumen. Bitumen is produced through distillation of crude oil [3]. One of the tests made for bitumen was determination of needle penetration. This test was used to determine the consistency of bitumen by using a penetrometer. In the test the needle of the penetrometer was placed on the surface of the bitumen and the machine automatically pressed the needle into the bitumen under specified conditions of temperature, load and loading duration. The depth of the penetration reflects the hardness of the bitumen. The deeper the penetration, the softer the bitumen is. One of the challenges in this test was to get the needle on the surface of the bitumen, because the water in the testing pool was reflective, and it was hard to see where the tip of the needle was. (Picture 1.)

PICTURE 1. With a penetrometer we were able to test the hardness of the bitumen (pictures: Jenna Niemelä)

Making Asphalt Sample

The first step of making the final asphalt mass is to make a mixture that includes aggregate and a filler. Then the mixture is poured into a mixing vessel after which the vessel is lifted onto a scale, and the specified amount of bitumen is included into the mixture. Next, the mixture is blended with a portable drill to make sure that the bitumen and aggregate are properly blended. At the same time, a heated mold for the final asphalt sample is assembled and lubricated to prevent the mixture from sticking into the mold. The mold includes a base plate and two collars. Then the mold is put into a machine called Marshall compaction hammer which then compacts the asphalt piece with 50 impacts. When the machine stops, the mold is turned upside down and another 50 impacts are struck. After the sample has been compressed, it is left to cool down before removing the mold. Doing this test was the most fascinating part of the whole laboratory experiment because we could do a lot ourselves and we could see what goes into the asphalt mass. (Pictures 2 and 3.)

PICTURE 2 and 3. The process of making an asphalt sample (pictures: Jenna Niemelä)

Conclusion

These kinds of pavement research laboratories exist so that asphalt companies can have information about their products, have better quality in their products and make sure that the asphalt meets the given requirements. Asphalt has an important role in our daily activities. For example, when we travel somewhere be it on foot or by a vehicle, asphalt roads are used so it is important that the asphalt is durable and of high quality.

The integration of English language with the professional subject maintenance and paving was well executed. Combining English language and a course having a professional value to civil engineering students, makes the learning of English terminology more meaningful and interesting. Because the laboratory classes were conducted in Finnish, there were some difficulties in translating the words into English, despite having the SFS standards in English. But in the end when we just read the standards multiple times, the contents of the English standards opened to us better and we could explain the words and the concepts better in our own words.

This way of studying vocational subjects is a nice variation instead of ordinary lessons. It was fun to do the tests ourselves, instead of just watching teachers doing them. This way of learning makes it easier to remember everything we studied during those two days in the laboratory.

Hypén Laura, Oulu University of Applied Sciences
Civil Engineering Student

Niemelä Jenna, Oulu University of Applied Sciences
Civil Engineering Student

Hedström Heidi, Oulu University of Applied Sciences
Senior Lecturer
Building services, energy engineering and civil engineering

References

[1] Kiwa.com. 2020. PANK-hyväksyntä päällystealan laboratorioille ja testausorganisaatioille. Retrieved 4.11.2020. https://www.kiwa.com/fi/fi/palvelumme/pank-hyvaksynta-paallystealan-laboratorioille-ja-testausorganisaatioille/

[3] Suomen Standardisoimisliitto SFS Ry. 2020. Retrieved 4.11.2020. https://sfs.fi/

[2] Chen, J. 2020. Terms. Bitumen. Investopedia. Retrieved 4.11.2020. https://www.investopedia.com/terms/b/bitumen.asp

Pysyvä osoite: http://urn.fi/urn:nbn:fi-fe202101272854