No 11 (2024)

On August 20–23, 2024, the International Conference of Manufacturers of Dry Building Mixes – Baltimix was held in Perm.

The conference is organized by the QUINTET event agency (St. Petersburg) with the scientific support of the National Research University MGSU (Moscow) and the participation of representatives of the Russian Union of Builders; the Association «National Association of Manufacturers of Building Materials and the Construction Industry» (NOPSM); the Russian Gypsum Association; the Association «Union of Manufacturers of Dry Building Mixes».

The general sponsor of the conference this year was the Perm scientific and production company Khimprom, which specializes in the development, production and implementation of unique chemical reagents and technological solutions in various branches of industry

The sponsors were manufacturers of chemical additives and construction equipment: POLYPLAST Group (Novomoskovsk, Tula region); Kedres LLC (Moscow); Stroymechanika Group (Tula) and Velcoms+ LLC (Moscow), Touching Stands Factory (Yekaterinburg).

2024 was a record year in terms of the number of participants – more than 300 specialists from 167 companies, 55 of which are manufacturers of dry building mixes; 22 are manufacturers of raw materials; 44 are manufacturers of chemical additives; 16 are equipment manufacturers.

The ongoing sanctions pressure did not become an obstacle to maintaining the status of «internationality» – business representatives from Kazakhstan, Armenia, China, and Belarus took part in the event. As part of the business program, 36 reports were heard at the plenary sessions.

The article examines current areas of application of additive manufacturing in construction (AMC, 3DCP) technology, including workshop and field printing of objects from 1 to 3 floors. The potential of the modified dry construction mixes market segment development associated with the production of materials for additive manufacturing in construction is shown. This potential is due to the active development of the global construction 3D concrete printing market and the multiple growth of the domestic individual housing construction market, supported by the high interest of the population in residential buildings up to 2 floors high. A survey and questionnaire of dry construction mixes manufacturing companies from different regions of the Russian Federation was conducted as part of the monitoring study to obtain up-to-date information on the state and trends in the production of materials for AMC in Russia. The article presents information on the production volumes of materials for additive manufacturing in construction in dynamics over the past 5 years, and also provides information on key market participants and companies ready to fulfill orders for the production of pilot industrial batches of dry construction mixtures for additive construction production in various regions of the Russian Federation upon receipt of relevant requests from interested participants in the Russian construction 3D concrete printing market.

Currently, permanent formwork made of high-strength steel fiber concrete (hereinafter SFB) is used in the construction of structures of nuclear power plants (hereinafter NPP). The use of reinforced formwork blocks with permanent formwork from SFB makes it possible to implement a precast-monolithic construction method, significantly increasing the speed of erection of blocks. At the same time, the use of this technology leads to problems of quality control of the laying of monolithic concrete, where it is hidden inside an armored block with permanent formwork. Experimental studies have been carried out to search for defects of various types and sizes inside the formwork block using the main methods of concrete flaw detection: through ultrasonic sounding, ultrasound tomography, radiography (georadar). Recommendations are given on ways to control the quality of monolithic concrete placement. It has been established that the most suitable method of control is ultrasound tomography, which allows to identify a defect behind a permanent steel-reinforced concrete formwork.

Vermiculite deposits are a heterogeneous array of micaceous minerals of varying degrees of hydration with a significant number of host rocks.The development of technology and equipment for both the enrichment of vermiculite ores and for the swelling of vermiculite and hydrosludes should be carried out taking into account their mineralogical features and the composition of the host rocks. The UralNIIstrom Institute has developed a series of installations for the enrichment of vermiculite ores and the production of expanded vermiculite. The developed installations are successfully operated in the Russian Federation/ and abroad.

The water resistance of concrete based on gypsum-cement-pozzolanic binder (GCPB) plays a critical role in ensuring the durability of products and structures, so finding new ways to increase it is one of the key tasks for these materials. Today, the most widespread method of modifying GCPB concrete with chemical additives that belong to the class of water-repellent according to GOST 24211–2008, giving it water-repellent properties. However, recently, especially abroad, so-called hydrophilic crystalline additives have become in demand, which are used to increase the water resistance grade of concrete. It is achieved by clogging its microstructure with needle-shaped new formations formed during the chemical interaction of the components of the additive with the hydration products of clinker minerals of the cement binder. The work carried out a comparative assessment of the effectiveness of six types of foreign chemical additives belonging to the class of hydrophobic and hydrophilic on such properties of GCPB concrete as strength, density, water absorption, water resistance according to the softening coefficient. It was established that the hydrophilic crystalline additive “Flocrete WP Crystal” showed the greatest efficiency for GCPB concrete, which, at a dosage of 2% by weight of the binder, significantly increased the softening coefficient (1.09) and reduced water absorption (3.2%) in comparison with non-additive GCPB-concrete (0.89 and 7.2%, respectively). Obviously, this will increase the durability of GCPB concrete and open up new possibilities for practical application in construction.

The existing methods of obtaining cellular concrete products with a variatropic structure are analyzed. It is revealed that each of them has its own advantages and disadvantages. A new technology for the production of cellular concretes of variable density has been developed, which makes it possible to manufacture construction products in Vietnam from local raw materials with high performance characteristics and meeting modern requirements for energy efficiency and durability.According to the test results, it was found that at the hardening age of 28 days, the average density in the dry state and in the state of normal humidity is in the range of 1085–1608 and 960–1517 kg/m³, respectively. Strength tests have shown that the developed concrete reaches an average compressive strength of 13.5–25.4 MPa on the 28th day of hardening. It can be concluded that the combination of foam and gas-forming components used in the formulation made it possible to obtain cellular concrete with an anisotropic structure, having the required indicators of compressive strength and average density in a wet state, which will be in demand in Vietnam during the construction of facilities for various purposes.