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A visible and long-wavelength photocured epoxy coating for stone protection

An epoxy coating modified by PDMS hydroxyl terminated is presented in this paper in order to evaluate its potential use as a protective of a stone surface. With a view to its use in restoration sites, visible and long-wavelength photoinitiated cationic polymerization is proposed here. The system investigated is based on a crosslinking mechanism which shows remarkable advantages for stone protection, such as the low toxicity of the products and facility of mixture preparation.

The plasters of the Sacro Monte of Varallo Sesia. From the characterisation to the proposition of a restorative mix

In this paper, the systematic physical-chemical characterisation of historical plasters of the Sacro Monte of Varallo Sesia, Italy, the study of the local constructive techniques, as well as the evaluation of new restoration plasters is presented. The selected samples (from XVI to XVIIIth centuries) are in a quite good state of conservation despite the prolonged exposition to weathering agents.

Improvements in self-consolidating cementitious composites by using micro carbonized aggregates

There is growing interest in the use of self-consolidating cementitious systems in construction industry. The present research was conducted to enhance the mechanical performance of cement composites by the utilization of micro-sized inert particles. This paper deals with the synthesis of micro-sized inert carbonized particles from hemp hurds. The synthesized carbonized particles were characterized by field emission scanning electron microscope (FESEM). These particles were further used as additive in self-consolidating cement composites. Total of four different wt% additions (i.e.

Experimental Investigation on Use of Wheat Straw Ash and Bentonite in Self-Compacting Cementitious System

In this research, we evaluated the feasibility of wheat straw ash and bentonite (raw and heated at 150°C for 8 hrs) as secondary raw materials in self-compacting paste (SCP). The fresh and hardened properties of SCP formulations including water and superplasticizer demand, flow behavior, compressive and flexural strength development, water absorption, and acid attack resistance were evaluated. Moreover, porosity, microstructural, and mineralogical investigations were also carried out on SCP formulations.

Epoxy monomers consolidant for lime plaster cured via a redox activated cationic polymerization

Epoxy resins, widely used in conservation, still remain controversial materials. Considering some of the drawbacks that currently limit the application of epoxy consolidants, we present the application of the cationic ring opening polymerization as a novel method to cure the epoxy monomer in the restoration field. The cationic polymerization was carried out through a redox system based on the reduction of the iodonium salt in the presence of ascorbic acid catalyzed by a copper salt. The use of this initiator system for carrying out a suitable consolidant for lime plaster is considered.

Diagnosis of the surface layer damage in a 1960s reinforced concrete building

This work aimed to determine the degradation causes of the Palace of Public Works located in S. Giovanni square in Turin (Piedmont, Italy). The samples collected from the surface layer were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric coupled with differential thermal analysis (TG-DTA), mercury intrusion porosimetry measurements (MIP) and phenolphthalein test. Metallographic and elemental analyses were also carried out on the steel reinforcing bars.

Biological response to purification and acid functionalization of carbon nanotubes

Acid functionalization has been considered as an easy way to enhance the dispersion and biodegradation of carbon nanotubes (CNT). However, inconsistencies between toxicity studies of acid functionalized CNT remain unexplained. This could be due to a joint effect of the main physicochemical modifications resulting from an acid functionalization: addition of surface acid groups and purification from catalytic metallic impurities. In this study, the impact on CNT biotoxicity of these two physiochemical features was assessed separately.

An Acrylic Latex Filled with Zinc Oxide by Miniemulsion Polymerization as a Protective Coating for Stones

An acrylic latex filled with ZnO by miniemulsion polymerization are developed for stone protection. The main latex chemical properties are determined through dynamic light scattering and differential scanning calorimetry measurements. Contact angle determination, capillary water absorption, scanning electron microscopy observations, and colorimetric measurements are also used to evaluate the coating. The accelerated photo-aging of the dried films are monitored by infrared spectroscopy.

Preparation and Structural Characterization of Rapidly Solidified Al-Cu Alloys

Rapidly solidified Al100-x-Cux alloys (x=5, 10, 15, 25, 35wt%) were prepared and analyzed. High cooling rate increased the Cu solubility in α-Al matrix. The influence of the cooling rate on Cu solubility extension in Al was experimentally simulated. Thus the pouring was performed in metallic die and by melt spinning-low pressure (MS-LP) technique. Melt processing by liquid quenching was performed using a self-designed melt spinning set-up which combined the cooling technology of a melt jet on the spinning disc with the principle of the mold feeding from low pressure casting technology.

New generation of brake callipers to improve competitiveness and energy savings in very high performance cars

This paper concerns with the optimisation of the innovative rheocasting process to produce a new generation of brake callipers, characterised by very high reliability and strength. The attained very promising properties favoured their use on a very high performance car and the presented technique can be further extended for other important challenging applications. The prototype components are produced using T6 heat treated A357 alloy. Results on the samples machined directly from the produced callipers are in detail described and analysed.