Magazine Ehitaja, March, Lauri Leet

Facade elements with titanium dioxide were used for the Karl Storz Video Endoscopy Estonia building.

One of the latest innovations of the concrete industry that is always looking to innovate is using titanium dioxide in concrete. The substance familiar from the chemical industry makes the surface of the concrete bright, self-cleaning and supposedly also more environmentally friendly, but it does increase the price by approximately 3%.

The use of titanium dioxide in the concrete industry has been around for over ten years. Different titanium dioxide is available in both liquid and solid form, and is mixed in concrete or in coated concrete elements. One of Europe's leading concrete product design and manufacturing groups, Consolis, has carried out quite extensive research on the use of titanium dioxide in both gray and white cements, and has been studying the self-cleaning ability of elements of titanium dioxide for nearly 10 years.

In Estonia, AS E-Betoonelement, which belongs to the Consol Group, has been manufacturing concrete products with titanium dioxide. Quality manager of the company's production Aare Lessuk notes that they has not been deepened into chemical process of titanium dioxide or its development, rather it is being dealt with it´s practical form with the production of titanium dioxide in concrete elements. The company has not separately studied the ability of nitrogen compounds of titanium dioxide nitrogen compounds to be airborne, and it does not want to think about it. The main advantage of the titanium oxide concrete elements is the controlled benefit of their self-cleaning effect.

In Estonia, concrete elements containing titanium dioxide have been manufactured by AS E-Betoonelement who is a member of the Consolis Group. According to the recollections of the company’s quality manager Aare Lessuk, E-Betoonelement actually started experimenting with titanium dioxide in 2012 out of interest. They manufactured grey concrete test specimens with a diameter of 100x100x30 mm where they mixed in titanium dioxide in different quantities. After curing, they drew lines on the test specimens with a waterproof marker and left them in the early summer sun when the UV level in the air is relatively high. “We manufactured the test specimens in May, and in June, a month later, a considerable purification could be noted,” Lessuk explains and brings out comparative photographs that provide clear evidence that the line drawn with a marker is noticeably lighter in the photos from June.

The fourth volume percentage does not affect the properties of the concrete
E-Betoonelement uses titanium dioxide only in powder form. In the production of concrete, weigh the necessary quantities and add titanium dioxide as the sands and aggregates are mixed dry manually to the mixture.

Titanium oxide should be added to 4% of the company's current experience. "A certain amount will provide a satisfactory effect. If the substance is to be dosed more, it will affect the compressive strength of the concrete negatively. If you follow the 4% rule, titanium dioxide does not have a significant negative effect on compression strength, "says Aare Lessuk.

Sales director of E-Betoonelement Aare Pärna confirms that there is a moderate interest in concrete elements with titanium dioxide, and a certain number of customers are also ordering them. The price difference is also noticeable, adding titanium dioxide will increase the price of the concrete product by about 3%. With the production of titanium dioxide, the entire process must be thoroughly considered. The production process must be clean, with the titanium dioxide starting the concrete planers must be washed beforehand, the mixers are to be lubricated with cleaning agents and the first cleaner mixer thrown away, Lessuk explains the high cost of the product. "If the customer asks for the product, then we obviously offer it in the best possible way, although its production may also be a challenge for us," both Pärna and Lessuk confirm.

Elements with titanium dioxide made up approximately 3% of the volume of concrete elements manufactured in the Harku plant last year by the company. E-Betoonelement received the first orders for the manufacture of concrete elements with titanium dioxide two or three years ago. They have manufactured facade elements for a couple of detached houses; the most famous site is the Karl Storz Video Endoscopy Estonia production, service and office building at Pärnu Highway near Tallinn that was included among the nominees of the Concrete Building of the Year 2016. Also for the construction of the buildings of the Defence Forces. Karl Storz Video Endoscopy Estonia tootmis-, teenindus- ja büroohoone Near Tallinn on the Pärnu highway. Titanium dioxide elements are also supplied to the Defense Forces Ämari and Jõhvi barracks, and these elements are currently being completed for the construction of Tapa barracks.

COMMENT
Architects of the Karl Storz building: we wanted beautiful concrete surfaces
E-Betoonelement used titanium dioxide elements to manufacture facade elements in the production, service and office building of Karl Storz Video Endoscopy Estonia, nominated for the "Concrete Building 2016". The architect-designer of the building, architect Tõnu Oppi, architectural design firm Luhse & Tuhal, said that the goal was to achieve a light, natural-looking concrete surface. "We wanted to use ordinary gray concrete, and in cooperation with the concrete manufacturer, we found that the best solution for this is the use of titanium dioxide."
The facade of the building has been standing for about a year now and, according to Oppi, it may be noted that during this time the concrete surface has grown pleasantly and the building has become more attractive. "We believe that the use of titanium dioxide is the right choice for achieving better weather resistance and time-consuming, bright, pleasant surface concrete," Tõnu Oppi resizes.

WHAT IS WHAT
Titanium dioxide

Titanium dioxide is (subtle powder) a bright white, non-toxic, persistent solid which is mainly used as a pigment in paints and paper. When heated, it turns yellow, cooling white will return. In the light the matter substance becomes a semiconductor, which is why it is used to transform solar energy into electrical energy in solar cells.
The advantages of titanium dioxide concrete elements are their better resistance to weather conditions, self-cleaning of concrete surfaces and its brighter and lighter appearance. It has also been found that concrete walls treated with titanium dioxide clean the environment by binding nitrogen compounds from the air when exposed to UV radiation.