scholarly journals Novel Radon Sub-Slab Suctioning System

2013 ◽  
Vol 7 (1) ◽  
pp. 13-19
Author(s):  
Torben Valdbjorn Rasmussen
Keyword(s):  
Concrete Slab ◽  
Low Pressure ◽  
Expanded Polystyrene ◽  
Insulation Material ◽  
Pressure Reduction ◽  
Insulation Layer ◽  
Reinforced Concrete Slab ◽  
Floor Slab ◽  
Ground Floor ◽  
New System

A new principle for radon protection is currently presented which makes use of a system of horizontal pressurised air ducts located within the lower part of the rigid insulation layer of the ground-floor slab. The function of this system is based on the principles of pressure reduction within the zone below the ground-floor construction. For this purpose a new system of prefabricated lightweight elements is introduced. The effectiveness of the system is demonstrated for the case of a ground-floor reinforced concrete slab situated on top of a rigid insulation layer (consisting of a thermal insulation layer located on top of a capillary-breaking layer) mounted in turn on stable ground. The new system of prefabricated lightweight elements consists of the capillary-breaking layer and a pressure-reduction zone which is working as the radonsuction zone. The radon-suctioning layer is formed from a grid of horizontal air ducts with low pressure which are able to remove air and radon from the ground. Results showed the system to be effective in preventing radon infiltrating from the ground through the ground-floor slab, avoiding high concentrations of radon being accumulated inside houses. For the system to be effective, the pressure within the ducts must be lower than the pressure inside the house. The new principle was shown to be effective in preventing radon from polluting the indoor air by introducing low pressure in the horizontal grid of air ducts. A lower pressure than the pressure inside the building must be established. The prefabricated lightweight elements were integrated into the insulation layer below the material of the ground-floor slab. The element and the insulation material were made of expanded polystyrene. The new element can be handled by one man on site.

scholarly journals Improving the manufacturability of floor slabs by pre-installing elements that partially replace reinforced concrete and formwork

2021 ◽  
Vol 258 ◽  
pp. 09019
Author(s):  
Seyran Akimov ◽  
Olga Balakchina ◽  
Elvira Akimova ◽  
Vladimir Malahov ◽  
Vasilij Shalenny
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Expanded Polystyrene ◽  
Simultaneous Increase ◽  
Resource Saving ◽  
Reinforced Concrete Slab ◽  
Floor Slab ◽  
Subsequent Performance ◽  
Permanent Formwork ◽  
Floor Slabs

The article discusses well-known and perspective constructive and technological systems for the installation of monolithic and precast-monolithic floor slabs of civil and industrial buildings. It shows examples and expediency of using all kinds of inserts made of plastic and other light materials and products for replacing a part of heavy monolithic reinforced concrete. An original resource-saving method for the installation of precast-monolithic floor slabs with a simultaneous increase in the degree of their construction readiness is proposed. This effect is achieved by reducing their own weight and the use of permanent formwork. Reduction in own weight of the precast-monolithic floor slab is ensured by the use of volumetric lightweight trapezoidal or rectangular inserts, preferably made of expanded polystyrene, during its installation. The use of permanent formwork will eliminate the need for the subsequent performance of labor-intensive finishing and insulation works. To confirm the effectiveness of using the proposed method of precast-monolithic floor slab installation, the operation of two floor slabs was modeled in the LIRA SAPR computing complex - the proposed reinforced concrete innovative slab and a solid reinforced concrete slab. Having analyzed the calculated forces, deformations and the corresponding consumption of reinforcement and concrete, comparative indicators were obtained for the proposed innovative slab and for a typical solid floor slab. As a result, significant savings in material and cost have been proven.

scholarly journals Analysis of the causes of damage to the RC floor slab in the underground garage

2019 ◽  
Vol 284 ◽  
pp. 06004
Author(s):  
Piotr Matysek ◽  
Michał Witkowski
Keyword(s):  
Concrete Slab ◽  
Technical Documentation ◽  
Synthetic Resin ◽  
Control Material ◽  
Reinforced Concrete Slab ◽  
Floor Slab ◽  
Entire Thickness ◽  
Rc Slab ◽  
Service Building ◽  
Material Tests

The article presents the results of testing a damaged reinforced concrete slab, which is located in the underground garage constituting the two lowest floors of a residential and service building. During the tests numerous cracks in the slab were inventoried. Some cracks covered the entire thickness of the RC slab and floor layers made of synthetic resin. The result of these damages was penetration through the slab of water from molten slush and the need to limit the parking places on the lower level of the garage. Conducted analysis of technical documentation, analysis of damage morphology, control material tests and structure computations allowed assessment of the causes of existing damages to the floor slab and ability to develop recommendations regarding the methods of its repair.

scholarly journals Numerical Analysis of the Impact of Thermal Spray Insulation Solutions on Floor Loading

2020 ◽  
Vol 10 (3) ◽  
pp. 1016 ◽  
Author(s):  
Anna Szymczak-Graczyk
Keyword(s):  
Polyurethane Foam ◽  
Thermal Insulation ◽  
Concrete Slab ◽  
Load Capacity ◽  
Minimum Energy ◽  
Bending Moment ◽  
Insulation Material ◽  
Elastic Substrate ◽  
Floor Slab ◽  
The Impact

The paper presents the effect of considering the substrate under the floor—insulation in the form of closed-cell polyurethane spray foam, which is used for insulating surfaces particularly exposed to mechanical impact. The layer of thermal insulation was made by spraying, which prevents the occurrence of thermal bridges due to tight filling of the insulated space. It seems extremely important to adopt the appropriate material characteristics of an insulating layer. The basic thermophysical properties of polyurethane foam justifying its choice as an insulation material were the values of its thermal conductivity coefficient (0.022 W/(mK)) and density (36 kg/m3). However, what was the most important for the calculations provided in the work was to determine the stiffness of the foam subgrade so as to assess its impact on the floor load capacity. The paper includes calculations for a floor slab characterized by a static diagram, with all edges free (unfixed), loaded in strips circumferentially. The reinforced concrete slab was 6 × 6 m long, 0.25 m thick, and made of C20/25 concrete resting on an elastic substrate. Calculations were made for two variants taking into consideration two values of subgrade stiffness. The first variant concerned the subgrade stiffness for sprayed polyurethane foam insulation. On the basis of laboratory tests in situ made according to the standard procedure, its average value was assumed as K = 32,000 kN/m3. The second, comparative, computational variant included the subgrade stiffness equal to K = 50,000 kN/m3. A variation approach to the finite difference method was used for static calculations, adopting the condition for the minimum energy of elastic deformation while undergoing bending that was accumulated in the slab resting on a Winkler elastic substrate. Static calculations resulted in obtaining the values of deflections at each point of the discretization grid adopted for the slab. The obtained results have proved the necessity of calculating the floor as a layer element. For the reference substrate with the subgrade stiffness K = 50,000 kN/m3 that was adopted in the work, the value of the bending moment was 17% lower than when taking into account that there was thermal insulation under the floor slab, causing an increase in the deflection of the slab and an increase in its bending moment. If a design does not include the actual subgrade stiffness of the layer under the floor slab, it results in an understatement of the values of the bending moments on the basis of which the slab reinforcement is designed. Adherence of insufficient concrete slab reinforcement may cause subsequent damage to floor slabs.

Numerical Simulations of Rockfall Protection Retaining Wall Joined to Steel-Pile Foundation

2011 ◽  
Vol 82 ◽  
pp. 716-721 ◽  
Author(s):  
Satoru Yamaguchi ◽  
Hiroaki Nishi ◽  
Hisashi Kon-No ◽  
Shin Ya Omote ◽  
Norimitsu Kishi ◽  
...  
Keyword(s):  
Pile Foundation ◽  
Rational Design ◽  
Concrete Slab ◽  
Retaining Wall ◽  
Three Dimensional ◽  
Expanded Polystyrene ◽  
Test Results ◽  
Reinforced Concrete Slab ◽  
Steel Members ◽  
Rockfall Protection

In Japan, many rockfall protection walls have been constructed along the nationalhighways in mountainous areas. Up till now, usually these were gravity-type walls. However, ifthere is not much space between the wall and the edge of the cliff, it may not be easy to constructa normal type of wall. To rationally install the wall in these areas, a retaining wall connectedto a steel pile foundation attached to a two-layer absorbing system was recently developed.Here, in order to establish a rational design for this type of retaining wall, an impact responseanalysis was performed by means of three-dimensional elasto-plastic FE analysis. The two-layerabsorbing system used here is composed of a 15 cm thick reinforced concrete slab together with a50 cm thick expanded polystyrene (EPS) block. The retaining wall is connected to the steel pilesby inserting H-section steel members embedded in the wall. The applicability of the proposedFE analysis method was verified by comparing with the prototype impact test results.

Dimension and Frequency Profiles of Concrete Highway Bridges in New Madrid Region of Southeastern Missouri

1997 ◽  
Vol 1594 (1) ◽  
pp. 84-93 ◽  
Author(s):  
Ralph Alan Dusseau
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Highway Bridges ◽  
Ambient Vibration ◽  
Earthquake Hazards ◽  
Empirical Formulas ◽  
Reinforced Concrete Slab ◽  
Box Girder ◽  
Bridge Spans ◽  
New Madrid

The results of a study funded by the U.S. Geological Survey as part of the National Earthquake Hazards Reduction Program are presented. The first objective of this study was the development of a database for all 211 highway bridges along I-55 in the New Madrid region of southeastern Missouri. Profiles for five key dimension parameters (which are stored in the database) were developed, and the results for concrete highway bridges are presented. The second objective was to perform field ambient vibration analyses on 25 typical highway bridge spans along the I-55 corridor to determine the fundamental vertical and lateral frequencies of the bridge spans measured. These 25 spans included six reinforced concrete slab spans and two reinforced concrete box-girder spans. The third objective was to use these bridge frequency results in conjunction with the dimension parameters stored in the database to develop empirical formulas for estimating bridge fundamental natural frequencies. These formulas were applied to all 211 Interstate highway bridges in southeastern Missouri. Profiles for both fundamental vertical and lateral frequencies were then developed, and the results for concrete highway bridges are presented.

Use of Foam Polystyrene Waste in the Conditions of a Reinforced Concrete Products Factory

2020 ◽  
pp. 49-52
Author(s):  
S.E. YANUTINA ◽  
Keyword(s):  
Reinforced Concrete ◽  
Precast Concrete ◽  
Expanded Polystyrene ◽  
Insulation Material ◽  
Design Strength ◽  
Foam Polystyrene ◽  
Secondary Use ◽  
Concrete Blocks ◽  
Polystyrene Waste ◽  
Factory Laboratory

The relevance of research in the factory laboratory of JSC «198 KZHI», which is part of the HC GVSU «Center», is dictated by the need to dispose of foam polystyrene waste that occurs in large quantities when producing the precast concrete. In the production of three-layer external wall panels, polystyrene heatinsulating plates of the PPS 17-R-A brand are used as an effective insulation material. The secondary use of PPS 17-R-A for its intended purpose, as a heater, is not possible. The volume of foam polystyrene produced varies from 25 to 45 m3 per month. Utilization (disposal) of foam polystyrene waste is an expensive undertaking. Its use as a filler in the production of expanded polystyrene blocks was tested in the factory’s laboratory to produce foam polystyrene concrete with specified physical and mechanical characteristics. The results of testing of expanded polystyrene concrete of classes B2.5 and B 7.5 are presented. It is shown that under the conditions of the reinforced concrete factory technology, the production of polystyrene concrete blocks is possible with the achievement of the design strength. The information presented in the article is aimed at motivating specialists who produce recast concrete to the possibility of using foam polystyrene waste for low-rise construction. Keywords: foam polystyrene, ecology, energy efficiency, foam polystyrene concrete, foam polystyrene heat insulation plates, precast concrete.

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