Lexikon

Road building

Brief history of asphalt

Asphalt is not an invention that followed cars, nor is it the invention of the late 20th century: the first European asphalt road and pavement appeared in France in 1838 and in Hungary in 1864. In fact, asphalt has been known and in use for much longer, practically for about 4000 years. The word comes from the Greek "aszphalt", which means "standard, permanent". It is the composition of 80-90 per cent breakstone and sand, 5-10 per cent bitumen, and 5-10 per cent filling, which is mainly fine limestone powder. The first asphalt material - "soil pitc" - was known even in 2000 BC. It was Herodotosz, who referred to it in his written works for the first time, as it was used as a binder for walls in the town of Ninive, Babylon. The walls of the Tower of Babel are considered to have been built this way. It was given the name "soil pitch" because bitumen (that is to say "pitch") could be found in nature mixed with soil and clay-bearing sand. In Babylon the stone cover of streets was cemented with asphalt material: Nabukodonozor built the road to the temple of Sun-god by placing road-metal asphalt on brick base topped with carved paving.

The foregoer French

Although road building was quite advanced in the Ancient Ages, hardly any new roads were built after the collapse of the Roman Empire, as cheap labour source disappeared with the slave society. Transportation by sea bloomed, then railway also appeared, but it could not solve the problem of freight and transit. It was France, who first took actions and built roads from the 17-18th century. In addition, Louis XIV established the "School of Bridge and Road Building", which might as well be called the first technical university. An engineer from Paris, de Coulaine discovered asphalt stone again (i.e. limestone with 10-20 percent bitumen content) as a natural road building material. In the 1830s he used it to make an experimental road with rolled road-metal. However, it failed because it went wrong during a couple of days due to high traffic, as there was nothing to cement the breakstone. After the failure the solution was quite clear for him: some adhesive must be used. It was bitumen. Earlier it was taken from soil pitch, today it comes from the distillation of oil. (Its name is originated from the Latin "pix tumens", which means "burning pitch".) Coulaine mixed crashed, granulated asphalt stones with clear bitumen and then heated it. This hot pulp was poured onto the base and levelled away to make a smooth new cover. The first asphalt pavement was made this way in Rue Berger in Paris in 1838. That is the material - coulé - which is now known as cast asphalt, in which breakstone, filling and a larger quantity of bitumen are fixed together without leaks making compaction during fell unnecessary. The material was a great success, but it was only worth using where asphalt stone was found nearby, such as some regions of France and Switzerland. After the great results of pavements, roads were also covered with cast asphalt, but it was not so successful. Due to high traffic the cover started to get worn-out soon, and because of the wrong dosage of bitumen it became either disrupted or too soft. Even, on hot summer days it became liquid and vehicles practically stuck in the bitumen pulp.

The American way

While experiments went on to perfect cast asphalt in Europe, a new product was to be invented in the US in the 1870s. This new product was "comprimé", id est agglomerated asphalt, today known as rolled asphalt. (The pulp also known as asphalt concrete has the void volume of 2-5 per cent, therefore it has to be agglomerated.) The experiments were absolutely successful. The first cover was built in 1876, and its composition was made according to the recipe of the experiments. Accurate instructions referred to its production as well. Asphalt stones were crashed into particular size, then the material was heated in order to get dehumidified and finally it was mixed with the bitumen melted before. The asphalt pulp was spread hot on concrete base and finally agglomerated with rolls. At first natural bitumen was used e.g. from the asphalt lakes of Trinidad and Bermuda, then bitumen was generated by distillation of oil from the end of the last century. (The "water" of asphalt lakes is basically the mixture of soil, oil and detritus bed-rock left over, and it has bitumen content of 60-95 per cent.) Europe started to make rolled asphalt only around the turn of the century, constructing such covers especially in London, Paris and Germany.

Expressive walls

The tradition of building asphalt roads in Hungary had a special and interesting way, although was a bit behind other European states. In the middle of the 19th century our roads and streets were still uncovered. Then following the Latin saying as "via vita" (i.e. the way is life) István Széchenyi pointed out that the lack of roads and streets was a great barrier of the development of our country. Unfortunately, his warning was ignored. It happened only by chance that road building works started in the late 19th century, even with asphalt. In the spring of 1858 an engineer called Mihály Kovács made a trip to the area of Nagyvárad in Bihar County. He noticed that the bottom wall parts of houses - at the height of appr. 40-50 cms - were painted black in a few villages namely Alsó-, Felsőderna and Tataros. The residents of the villages told him that it was not paint, but a pitch-like material, which they could find near the villages and it protected the walls from getting wet. Kovács went to the spot immediately to make sure what he suspected to be real. It was a well-known material from his technical books, the so-called bitumen. Laboratory examinations proved his right. He searched a partner for large-scale production and together with István Popper started mining works in 1863. This bitumen was of high quality, and was found in large quantity below the surface up to the depth of 150 meters.

National Asphalt Industry Corporation

The son of the co-enterpriser - who is also a qualified engineer - had already read about the asphalt, the integrated cover created by using bitumen, that is why he travelled to Paris in 1864, to gain relevant experience. He saw the first asphalt pavement built in Rue Berger in 1838, which had been used for twenty-six years by then, but he also considered the carriage-road in front of the Conservatoire de Musique. After returning home he started asphalt production and fell immediately. The first national asphalt cover was made on the pavement in front of 21 Palatinus street (today Nádor street). In 1868 Jr. Kovács established the National Asphalt Industry Corporation with the financial support of Wiener Bankvereinl. Instead of the former immature asphalt plant, a new modern plant was established with four mixing machines in Orczy street. Transportation was also modernized. Hot asphalt was filled into horse-drawn tanks fixed on wheels, and it was heated to keep hot. The churn-dashers were rotated during transportation by a cog-wheel fixed on the wheel. When the material was delivered to a destination far away, it was made into hexagonal, so-called "masztix" biscuits on the plant; because they were easy to be transported in cooled condition, and it was easy to melt them on the spot. This production process needed high technological requirements, which could be found slightly funny these days, but proved to be useful at that time. An example for this was the method that said "a material ensures good quality if the water dropped on the surface of the ready asphalt evaporates with mild cracking". Or: "if wooden spoon can hardly get into the material, we need to add more bitumen". The first Hungarian asphalt covered street was built in Hatvani (today Kossuth Lajos) street. It was followed by streets in the Castle, then in the City (in Petőfi Sándor, Vörösmarty, József Attila, Dorottya, Nádor, Király streets, etc.).

In case of repairing roads the hot pulp is spread manually even today, but meanwhile the technology was developed. From the early 1870s drum was becoming widespread to perfect mixing. Hungarian asphalt was of high quality, which is proved by the fact that the samples were awarded with gold medal and a certificate in the World Exhibition in Paris in 1878.

Following the success in the capital, new mixing plants were established in most big cities, such as Nagyvárad, Pécs, Szeged, Győr, Arad, etc. Before the end of the century over 900 thousand square metres of road covering and 2,6 million square metres of pavement were made of asphalt.

Further improvements were made by the domestication of roll-asphalt covering. However, the first experiments failed. The first covering was built involving an American expert in Nagyvárad in 1906, but it was totally destroyed within a week. The "expert" turned out to be fraud. The failure put a stop to building similar road coverings, but later there were well-prepared sections such as the covering of Margaret dock, Alkotmány street and Szabadság square in our capital city.

After the First World War the mines of Derna and Tataros were attached to the area of Romania, so only the much more expensive Mexican and Trinidad bitumen was available. After 1926 primarily rolled coverings were made in high quality. It was proved by several huge orders from Vienna and Prague. Mass production of asphalt started in Hungary some time in the 1960s with the construction of roads and motorways. But here starts another story...

About concrete

Concrete is an artificial construction material composed of hydraulic adhesive (cement), water and a mixture of other additional materials. Concrete solidifies and hardens after mixing with water and placement due to a physical and chemical process eventually creating a stone-like material.

The history of concrete

The Romans used the so-called Roman cement (with aluminium and silicium fragments) to build roads, baths and water pipes. The concrete first appeared as a fined technique in the dome structure of the Pantheon. The structure is getting thinner and thinner from the bottom of the dome towards its centre considering a favourable load. In 27 AD description of concrete was also mentioned in the architectural book of Pollio Vitruvius.

In 1779 Bry Higgins had stucco overcasting patented, which consisted of hydrated cement. He published his experience in an article with the title ?Experiments and Observations Made With the View of Improving the Art of Composing and Applying Calcareous Cements and of Preparing Quicklime?.

In 1793 John Smeaton pioneered the use of hydraulic lime in concrete, using peddles and powdered brick as aggregate. Basing on his observations he had the light tower in Cornwall rebuilt.

In 1800 concrete was first used in large quantity for the building work of the Bristish port, the West Indian Dokk, which was designed by William Jessop.

Between 1812 and 1816 the first concrete structure bridge was built in Souillac, France, which did not contain any reinforcement.

Several British, French and American patents came to life in the 1820s with the usage of lime in connection with cement and concrete e.g. James Parker had experiments with the so-called Parker (also known as Roman) cement.  ?Edgar Dobbs dealt with binding and gypsum.  ?Louis Vicat made lime added to clay.  ?Canvass White recognised natural cement. ?Maurice St. Leger and John Tickell succeeded to make such natural cement, which could harden even under water.  ?Ralph Dodd dealt with hammered iron poles inside concrete. ?Abraham Chambers and James Frost experimented with different types of cement.

In 1824 Joseph Aspdin, a British bricklayer, made the patent of Portland cement, which he named after the building stone extracted at Portland. This expression is in use nowadays as well.