Surface Plaster Research Articles

Mechanical behavior of masonry strengthened with coir fiber reinforced hydraulic cement mortar as surface plaster

Mechanical behavior of masonry strengthened with coir fiber reinforced hydraulic cement mortar as surface plaster

Experimental Research on Using Form-stable PCM-Integrated Cementitious Composite for Reducing Overheating in Buildings

This paper investigates the potential of using form-stable phase change material (FS-PCM) integrated cement mortars in building envelopes to prevent overheating and to improve summer thermal comfort. The FS-PCM integrated cement mortar was applied as the interior surface plastering mortar of a full-scale test hut and compared with identical test huts built on cement plasterboard (OCB) and gypsum plasterboard (GPB). The test huts were exposed to outdoor climatic conditions, and indoor thermal behaviours were continuously monitored throughout the summer period. The effects of PCM in reducing the overheating was analysed by the intensity of thermal discomfort (ITDover) and frequency of thermal discomfort (FTDover) for overheating during the summer days. The comparison between different test huts showed that the application of PCM integrated cement mortars reduced the peak indoor temperature by up to 2.4 °C, compared to GPB and OCB test rooms. More importantly, the analysis of overheating effects revealed that at lower intensive thermal discomfort levels, FS-PCM largely reduces FTDover. As the intensity of thermal discomfort increases, the reduction in ITDover becomes dominant. At highly intensive thermal discomfort levels, the reduction was neither apparent in the intensity of thermal discomfort nor the period of discomfort.

Effect of Roof and Diaphragm Connectivity on Dynamic Behaviour of the PP-band Retrofitted Adobe Masonry Structures

This paper discusses the shaking table test results of three PP-band (Polypropylene band) retrofitted quarter scale one-story masonry house models with different roof conditions. Better connections between masonry wall and roof connection are one factor to improve the seismic safety of the masonry houses. Past studies show that PP-band retrofitting improves the integrity of structural components and prevent the collapse of masonry structures during an earthquake. Although the effect of masonry unit type, surface plastering, the pitch of the PP-band mesh, PP-band connectivity in mesh and tightness of the mesh attachment to walls were studied by experiment program, the effect of the roof and its diaphragm connectivity on PP-band retrofitted masonry structure is nonexistent. Therefore, an experimental program was designed and executed for an understanding the effect of the roof and its connection on the dynamic behavior of the PP-band retrofitted box-shaped masonry house models. Results reveal that the PP-band retrofitted models with proper roof diaphragm improves the seismic behavior with respect to lateral drift, shear resistance and ductility.

Axial compression behaviour of reinforced wallettes fabricated using wood-wool cement panel

Wood-wool cement composite panel (WWCP) is one of wood based composite material that produced in a stable panel form and suitable to be used as building wall system to replace non-ecofriendly material such as brick and other masonry element. Heavy construction material such as brick requires more manpower and consume a lot of time to build the wall panel. WWCP is a lightweight material with a density range from 300 kg/m3 to 500 kg/m3 and also capable to support an imposed load from the building. This study reported on the axial compression behaviour of prefabricated reinforced wallettes constructed with wood-wool cement panel. A total of six specimens were fabricated using two layers of cross laminated WWCP bonded with normal mortar paste (Portland cement) at a mix ratio of 1:3 (cement : sand). As part of lifting mechanism, the wallettes were equipped with three steel reinforcement (T12) that embedded inside the core of wallettes. Three replicates of wallettes specimens with dimension 600 mm width and 600 mm length were fabricated without surface plaster and with 16 mm thickness of surface plaster. The wallettes were tested under axial compression load after 28 days of fabrication until failure. The result indicated that, the application of surface plaster significantly increases the loading capacity about 35 % and different orientation of the panels improve the bonding strength of the wall.

Axial compression behaviour of cross laminated wood-wool panel wallettes

This study reported on the investigation of the structural behaviour of wallettes fabricated using wood-wool cement panel (WWCP) under axial compression load. WWCP is a wood based product, which produced by mixing a wood-wool, cement and water and compressed to form a stable panel with dimension of 600 mm × 2400 mm × 50 mm. In the fabrication of wallettes, two parameters were considered which are wallettes without surface plaster denoted as WNP and wallettes with 16 mm thickness of surface plaster on both sides denoted as WP. The 50 mm thickness of WWCP was used and cut into size 300 mm and 600 mm length. The cut panels were then horizontally laid in two layers (each layer consists of two panel strips) at different panel orientation to form a 600 mm × 600 mm wallettes. The front and rear layer were bonded together using 15 mm thick of normal mortar mix at a mixing ratio of 1: 3 (Cement : Fine sand). A total of five wallettes specimens were fabricated and tested under axial compression load test until failure. The testing results indicated that, the application of surface plaster on both side significantly increased the load carrying capacity of wallettes about 31 % compared to the wallettes without surface plaster.

Thermal performance assessment of phase change material integrated cementitious composites in buildings: Experimental and numerical approach

This paper presents a comprehensive experimental and numerical investigation on thermal enhancement of form-stable phase change material (PCM) integrated cementitious composites, with the goal of applying as interior surface plastering mortars in building walls. The composite PCM fabricated on paraffin/hydrophobic expanded perlite (EPO) showed an apparent density and 28-day compressive strength of 1244.2kg/m3 and 17.9MPa respectively, when integrated into ordinary cementitious composite at 80% volume replacement of fine aggregate. The thermal performance of PCM integrated cementitious composites was experimentally assessed using a prototype test cell made with PCM integrated cement boards (PCMCB) subjected to realistic temperature cycles. The comparison study considers two reference prototypes made with gypsum plasterboards (GPB) and ordinary cement boards (OCB). It was found that the prototype incorporated with PCMCB reduced the peak indoor temperature by up to 2.8°C and 4.43°C during typical summer days and summer design days respectively, compared to the GPB test cell. Numerical simulations conducted on a multi-storey office building for the application of PCMCB as interior surface plastering mortars showed that the PCMCB could significantly reduce the peak indoor temperature and diurnal temperature fluctuations. Indeed, the interior surface application of PCM has limited cold storage at night, leading to reduced latent heat storage. However, cold storage of PCM could be improved by introducing night ventilation. The combined application of PCMCB and night ventilation reduced the peak indoor operative temperature by up to 3.4°C, as opposed to 2.5°C for building refurbishment with PCMCB only.

Performance of coconut coir reinforced hydraulic cement mortar for surface plastering application

This study was to investigate the effect of coconut coir on the strength and durability properties of cement-lime surface plaster mortar. The purpose of adding coconut coir into the mortar was due to coconut coir had a capacity in controlling cracking in the mortar. In this study, total 115 samples were prepared which were 100 cubes (150mm×150mm×150mm) and 15 beam prisms (100mm×100mm×500mm). Testing was included; water absorption, porosity, sorption rate for physical properties; acid attack resistance, alkaline attack resistance for durability properties; compression and flexural bending for strength properties. The samples were tested with mortar containing 0.125%, 0.25%, 0.50% and 0.75% of coconut coir. The percentage of coconut coir fraction was calculated based on the cement, lime, sand mix by mass. Test results show that, although compressive and flexural bending strength are not improving, but post crack properties such as ductility, residual strength, and toughness are increased with higher coconut coir fraction in the matrix.

Flexural strength and physical properties of fiber reinforced nano metakaolin cementitious surface compound

This study aimed at investigating the role of nano metakaolin (NMK) for enhancing the flexural strength and reducing the capillary water absorption of fiber-reinforced cementitious composites (FRCCs) for building surface plastering. Short natural fibers were added to white Portland cement (WPC) by different amounts of 0.5%, 1%, 1.5%, 2%, 2.5% and 3% by weight of cement. All samples were cured in water. It was found that as the amount of fiber increases the flexural strength increases up to about 2% by 82%, then after, a decrease in flexural strength was observed. The capillary water absorption increases with increasing fiber percent. In order to develop fiber reinforced nano-cementitious composite, different percentages of NMK ranging from 2% to 14% were used with the replacement of cement keeping constant fiber content of 2%. The phase composition and microstructure of the formed hydrates were studied using thermogravimetric analysis (TGA), X-ray diffraction (XRD) & scanning electron microscope (SEM). Additional increase in the flexural strength by about 67% was achieved at 10% NMK content. The capillary water absorption generally decreases with increasing replacements of cement by NMK. A decrease of about 50% was observed at 10% NMK.

Development of Digital Imagine Correlation (DIC) Method for Three-Dimensional Rugged Surface of Construction Material

Digital Image Correlation, DIC method is developed a low-cost digital image correlation coefficient method based on advanced digital cameras and high-speed computers. Traditionally, two or more cameras are widely applied for conducting 3-D monitoring. There are numerous parameters need to be accurately calibrated. Therefore, the results of 3-D accuracy are worse than that of 2-D accuracy. The feasibility of a single camera to collect image to analyze the three-dimensional rugged surface of material is proposed in this study. A three-dimensional facial mask-like human makeup test and plaster cast are used to test. The test results reveal that the coordinate error between these two photos of the three-dimensional facial mask-like human makeup test is only 0.002mm and the absolute displacement, rotate on z-axis, strain on z-axis and von Mises strain of analysis results are extremely close to the real surface plaster cast.

9. Aggregates for mortar

This chapter, which is concerned with aggregates for mortars, necessarily introduces some degree of overlap with Chapter 8. However, there are major differences between mortars and concretes, arising mainly from the manner of their use. The term ‘mortar’ is used in the building industry to denote a mixture of natural sand or other fine aggregate and some binding agent, used as a jointing or a surface plastering and rendering material (Fig. 9.1). In the United Kingdom the demand for building sand grew steadily up to 1973 to reach a peak of 23.6 Mt, representing some 18% of the total sand and gravel production (HMSO 1989) for the country. Since then it has fluctuated considerably, falling to 15.7Mt in 1981 but rising again to 21.89 Mt in 1988 (Fig. 9.2). It should be noted that the output figures for building sands are far in excess of figures for mortar production. Until about 30 years ago the choice of binders in the UK was limited to lime or cement or cement-lime mixes. Mortars made with lime alone as binder are no longer used for building except for some specialist applications in the repair of historic buildings. The choice of cement binders has been widened to include masonry cements (specially blended mixtures of Portland cement with finely divided mineral plasticizers and air-entraining agent). Increasingly, air-entrainment in mortars, not only to confer frost resistant properties but also to aid workability, is being used even with cement/lime/sand mortars.

On painted ceilings…the techniques of Baroque murals in England

Abstract This paper discusses the findings of an analytical investigation into the materials and techniques of five Baroque wall paintings, produced by an art historically and technologically coherent group of painters, during the late seventeenth and early eighteenth centuries in England. The analysis attempted to define the composition and stratigraphy of the paint, ground, sealant and surface plaster layers, as well as the range of pigments and organic media in use. Later restoration and conservation materials, in particular varnishes and retouchings, were noted.