Bitumen Sheet Research Articles

Insufficient dimensional stability of bitumen sheets as a source of flat roof defects

One of the frequent sources of flat roof faults is failure of the top layer of a multilayer bitumen sheet system in cross-connections. One of the possible causes of this disorder is failure to observe technological discipline. The paper deals with how the full melting of the bitumen sheet influences its possible shrinkage during the roof exposure. Bitumen sheets with a polyester carrier which is not reinforced with fiberglass fibers are burdened with shrinkage effect. The preload is introduced into these belts during production. The aim is to show how is the effect on loosening the preload in the carrier layer with full-scale smelting during the realization of the waterproofing layer. The preload loosening experiment, expressed by the dimensional stability test according to ČSN EN 1107, was performed in a laboratory on two bitumen sheets.

Influence of the frontal joint of the bitumen sheet on the final strength of the joint

This article focuses on the frequently discussed topic how to make the frontal joints of bitumen sheets with coarse-grained surface coating. Bitumen sheets have a spill in the place of these joints. Insufficient strength of the frontal joint is one of the possible faults in waterproofing using bitumen sheets. The paper compares different ways of performing these joints in terms of force stress based on surface treatment. Surface treatment is possible by immersing the sprinkle, scraping it into the bitumen sheet mass, or simply heating the surface and leaving it unpainted.

Issue of Changes in Adhesion of Bitumen Sheet to Primary Layer over the Course of Time in Multilayer Waterproofing during Shear Testing

This paper is based on research dealing with defects that appear on concrete bridge decks with an insulating layer from asphalt strips on the interface between the asphalt strip and its basis. The durability and lifespan of the bearing structure of concrete bridge is determined by insulating layer that constitutes, together with the primary layer and a protective layer, the insulation system of the concrete bridge deck. Paints based on low viscosity epoxy resigns are one of the possibilities of primary layer implementation. These paints may be performed as anchoring-impregnation paints that usually represent single layer paint on the bridge deck surface. Sealing layer is another variant. Sealing layer is a multilayer consisting of anchoring- impregnation paint and sealing paint. The primary layers mainly provide vapour closing of the concrete surface, and partly, through roughening the surface, contribute to adhesion of bitumen (asphalt) insulation (waterproofing) layer. Application of the primary layer has been spreading in the Czech Republic since the 1990s. Now, after approximately 30 years of use defects in these epoxy based sealing layers at the interface between primary layer and waterproofing layer of reinforced bitumen sheets (RBS) are being solved in the Czech Republic. After performance of the first test focusing on breaking-strength, it was found that the strength between the asphalt and the primary belt layer in some types of low-viscosity resin-epoxy decreases and after a certain period of time again increases, depending on the time. Tensile strength test is carried out on a sample of asphalt strip, which is fused onto the substrate with a primer coat. It was therefore proceeded to test the shear adhesion. Testing of the shear adhesion is conducted on the entire concrete deck waterproofing system. It was supposed that the decrease of adhesion at this test become evident in higher extent. Adhesion tests in shear were performed on the primary layer consisting of an anchoring impregnation coating and sealing layer.

The problem of the compatibility of bitumen sheets for the reconstruction and ehabilitation of roofs

During the renovation of flat roofs, the waterproofing layer is often repaired locally rather than completely replaced. When making such repairs, it is very important to know whether the proposed bitumen sheets are compatible in order to prevent delamination and the release of the joints. This paper deals with the determination of the resistance of bitumen sheet joints against peeling when combined with different bitumen materials. On the basis of the described test methodology it was possible to determine whether the selected bitumen materials were compatible with bitumen sheets. As part of the experiments, modified bitumen sheets with plastomers (PO), oxidized bitumen (OX), and elastomers (SBS), were tested.

Characteristics of the mechanically fastened joints of one-layer bitumen sheets

The system of mechanic fastening is one of the most frequently used variants of roof membrane stabilization against the impacts of wind sucking. With the growing number of applications of mechanically fastened roofs the number of defects is also growing. We particularly see them in the joints of waterproofing membranes. The contribution is thus dedicated to examination of mutual dependence between the type of the carrier and the strength characteristics of mechanically fastened joints of these sheets. Bitumen sheets with different types of carrier used for onelayer mechanically fastened waterproofing membranes of flat roofs were chosen as samples. The above mentioned dependence is frequently stated in the practice, but is not explicitly documented. The aim of the contribution is to confirm or refute a hypothesis that a relation between the bitumen sheet carrier type and the strength of their joints exists. The results were arranged on the base of statistic evaluation of data obtained by laboratory measurement.

Characteristics of the mechanically fastened joints of one-layer bitumen sheets

The system of mechanic fastening is one of the most frequently used variants of roof membrane stabilization against the impacts of wind sucking. With the growing number of applications of mechanically fastened roofs the number of defects is also growing. We particularly see them in the joints of waterproofing membranes. The contribution is thus dedicated to examination of mutual dependence between the type of the carrier and the strength characteristics of mechanically fastened joints of these sheets. Bitumen sheets with different types of carrier used for onelayer mechanically fastened waterproofing membranes of flat roofs were chosen as samples. The above mentioned dependence is frequently stated in the practice, but is not explicitly documented. The aim of the contribution is to confirm or refute a hypothesis that a relation between the bitumen sheet carrier type and the strength of their joints exists. The results were arranged on the base of statistic evaluation of data obtained by laboratory measurement.

Dynamic Thermal-energy Performance Analysis of a Prototype Building with Integrated Phase Change Materials

The use of PCMs for improving buildings’ thermal comfort conditions and reducing summer cooling need has been largely investigated in the last decade. The capability of these materials of storing heat in latent form has been pointed out, especially when integrated in building envelopes. This paper deals with the analysis of the benefits in terms of buildings’ energy saving generated by the integration of PCMs inside two types of membrane for roofing applications, i.e. a traditional bitumen membrane and an innovative cool polyurethane-based membrane. To this aim, the dynamic simulation of the energy performance of a test-room was carried out. Four configurations were simulated and compared: (i) roof covered by a bitumen sheet membrane, (ii) roof covered by a cool membrane, (iii) the cool membrane with integrated PCMs, and (iv) the bitumen membrane with integrated PCMs. Both winter and summer conditions were studied. The results showed that PCMs integrated into the cool membrane are able to guarantee a 10.4% cooling energy saving, while PCMs integrated into the bitumen membrane generate a 12.6% of energy reduction for cooling if compared to the only bitumen membrane. The same roof configurations without taking into account the roof insulation layer generate a reduction of the cooling energy requirement of about 9.4% and 16.6%, respectively. In winter conditions, the reduction of the heating demand generated by the integration of PCMs inside the bitumen membrane is about 4.4% and 6.9%, with and without considering the roof insulation, respectively. Additionally, the heating energy saving generated by including PCMs into the cool membrane is equal to 5.4% and 8.4%, with and without considering the roof insulation layer, respectively. These results demonstrated that the integration of PCMs in both cool and non-cool roof membranes is able to reduce building energy requirement in both summer and winter conditions, especially in non-insulated roof configuration.

Bulk Density of Bitumen Sheets

This article deals with determination of bulk density of bitumen waterproofing sheets using different methods, namely calculation and experimental measurement. Volume density actually well reflects bitumen sheet composition. Composition of bitumen sheet is the factor that influences the hydro insulation function.

Bituminous emulsions and their characterization by atomic force microscopy

We present a new method for observing oil-in-water emulsions with a continuous water phase and a dispersed bitumen phase. The fine polydispersed bitumen micelles were adsorbed to an atomically smooth mica substrate and imaged in solution by atomic force microscopy in a liquid cell. The height of the adsorbed bitumen sheet in wet and dry states can be measured and the homogeneity of film formation by coalescence can be determined. Localization of surfactant onto and between bitumen micelles is also visualized.