Influence of Polymer Modifiers on Selected Properties and Microstructure of Cement Waterproofing Mortars

This paper presents the results of research on the influence of polymer modifiers: styrene-acrylic copolymer, vinyl acetate/ethylene (EVA), vinyl acetate/acrylic copolymer (VAAc), and VA/VeoVa/acrylic terpolymer on the water permeability and adhesion of cement-containing waterproofing mortars in concrete. The content of the polymers in the composition of the mortars was 15, 20 and 26% (m/m) in relation to the weight of the dry ingredients. Using microscopic methods, an attempt was made to analyse the relationship between the microstructure of the mortars and the properties of these polymers. The EVA and the vinyl acetate/acrylic copolymer, which were used in the form of dry powders, had the most favourable effect on water permeability and adhesion to the concrete substrate. They may prove to be useful for the production of one-component cement-containing waterproofing mortars. On the other hand, the VA/VeoVa/acrylic terpolymer modifier had the least favourable effect on the tested properties. For mortars with this modifier, the desired water-permeability parameters were not achieved. Depending on the amount of polymer modifier, the mortars were characterized by differences in watertightness, as established on the basis of changes in porosity and differences in the adhesion of the cement-polymer paste to the surface of aggregate grains. It was determined that the type of polymer and its dispergation properties influence the water permeability of mortars, as well as their adhesion to concrete substrates.

The Effect of Polymer Powder on the Cracking of the Subbase Layer Composed of Cold Recycled Bitumen Emulsion Mixtures

The research was aimed at assessing the effect of the redispersible polymer powder on the fracture resistance of a subbase made of a mineral–cement mixture with a bitumen emulsion. The test was performed at two temperatures, i.e., 0 °C and 20 °C. The prepared mixtures differed in the content of cement, asphalt emulsion, and polymer modifier. Cement and redispersible polymer powder were dosed in 1.5% steps from 0.5% to 3.5% while the amount of bitumen emulsion ranged from 0.0% to 5.0%. The SCB (semi-circular bending) tests carried out in the laboratory showed the dependence of the influence of the amount of binder and polymer modifier on the fracture resistance of the recycled subbase. Mixes containing a polymer modifier in their composition are characterized by a much higher resistance to cracking than traditional mineral–cement–emulsion mixtures. An example is the doubling of the framework’s fracture toughness (KIC) when the amount of the polymer modifier is increased from 0.5% to 2.0% with a constant cement content of 0.5%. The obtained results (KIC) in this case were 2.90 and 5.81. The key is the right ratio of polymer powder and cement in the base composition.

Performance Evaluation of Conventional and High Modulus Asphalt Concrete with Novolac Polymer Modifier Using Aashtoware Software

In order to changes the original asphalt characteristics, there are many additives have been used to produce or modify the High Modulus Asphalt Binder (HMAB). Even though the hard grade asphalt binder has some disadvantages, such as the aging process due to high mixing and compacting temperature, which can negatively affect the pavement performance, some other advantages include increasing stiffness modulus of asphalt binder and high resistance to permanent deformation. Also, using the hard grade asphalt binder will save construction costs by reducing the asphalt pavement thickness due to its high stiffness modulus. In Iraq, the Novolac modifier and its Cross-linking Agent (Hexamine) was used for the first time as a modifier for asphalt which can significantly improve the rheological properties of asphalt and its role in HMA. This study focuses on estimating the thickness reduction of flexible pavement due to using High Modulus Asphalt Concrete (HMAC). The reduction in permanent deformation and thickness of pavement were estimated for suggested pavement structure sections implemented HMAC mixture compared with the pavement section implemented conventional mixtures using AASHTOWare software version 2.3. The analytical results indicate that adding 4% of Novolac modifier and 15 % of Hexamine (form weigth of Novolac) is reduced the permanent deformation and bottom up cracking by 30% and 46 % compared to conventional mix, respectively. However, it can be concluded that adding Novolac polymer modifier enhanced the pavement performance.

Interfacial engineering tailoring the dielectric behavior and energy density of BaTiO3/P(VDF-TrFE-CTFE) nanocomposites by regulating a liquid-crystalline polymer modifier structure

For the first time, the effect of a rigid-liquid-crystalline polymer modifier structure on the dielectric behavior and energy density of BaTiO3/P(VDF-TrFE-CTFE) nanocomposites was investigated.

Utilization of Waste Plastics in Stone Mastic Asphalt for Infrastructural Applications

This paper reports an experimental study on the use of waste plastics in stone mastic asphalt (SMA) for infrastructural applications (e.g. roads, carparks and underground construction). The binders investigated were conventional bitumen, target bitumen (polymer modified bitumen) and waste plastics (recycled low-density polyethylene LDPE of 5 wt% and 10 wt% blends). The properties of bitumen were assessed based on its penetration value and softening point; while the performance of asphalt premix (or asphalt mixture) was evaluated based on its Marshall stability, flow and quotient. The asphalt mixture incorporating waste plastics (10 wt% LDPE blend) as polymer modifier could be a promising material for use in SMA for infrastructural applications.

Study of Deformation and Failure of Bitumens for Asphalt Mixtures under Dynamic Loads

The work presents results of the experimental study of dynamic compression of various modifications of bitumen: bitumen 40/60, polymer-bitumen binder and rubber bitumen. The tests were carried out using the Kolsky method. The tests were conducted for the sample temperature of-15 and 20 °C. It is shown that polymer modifier and rubber additives have a significant influence on the carrying capacity of the bitumen samples at slow loading, but they do not provide significant advantages in the dynamic tests. Strain rate dependence of maximum compressive stress was obtained for the bitumens. It is shown that this dependence can be predicted by the incubation time criterion. The values of the quasi-static and dynamic strength, characterizing the carrying capacity of bitumen at slow and fast loading, are defined.