scholarly journals Evaluation of Reducing NO and SO2 Concentration in Nano SiO2-TiO2 Photocatalytic Concrete Blocks

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7182
Author(s):  
Jong Won Lee ◽  
Sang Hyuk Lee ◽  
Young Il Jang ◽  
Hee Mun Park
Keyword(s):  
Solar Radiation ◽  
Environmental Performance ◽  
Sol Gel ◽  
Concrete Block ◽  
Full Scale ◽  
Nano Sio2 ◽  
Concrete Blocks ◽  
Environment Chamber ◽  
Photocatalytic Concrete ◽  
So2 Concentration

The use of titanium dioxide in concrete block pavements is a promising approach to reduce air pollution in the roadside. When TiO2 is used as an additive of cement concrete or mortar, it is not dispersed uniformly due to agglomeration between particles causing the degradation of photocatalytic reaction. To improve the photocatalytic performance of TiO2, the Nano SiO2-TiO2 (NST) has been developed by coating TiO2 with SiO2 as a support using the sol-gel method. The environmental performance of concrete blocks incorporating NST as an additive was evaluated using both laboratory and full-scale chamber experiments. It was observed from laboratory environment chamber testing that the NO reduction efficiency of concrete blocks with 4% NST ranged from 16.5 to 59.1%, depending on the UV intensity. Results of the full-scale chamber test on NST concrete blocks indicated that the NO and SO2 reduction efficiencies were 22.3% and 14.4% at a 564W/m2 of solar radiation, respectively. It was found that the increase in UV intensity and solar radiation had a positive effect on decreasing NO and SO2 concentration. In the future, the NST will be applied at in-service photocatalytic block pavements to validate the environmental performance in field conditions.

scholarly journals The Influence of Lime Solution in Kneading Water Substitution on Cement Roughcast and Mortar Coating

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4174
Author(s):  
André M. Santos ◽  
Ângelo J. Costa e Silva ◽  
João M. F. Mota ◽  
João M. P. Q. Delgado ◽  
Fernando A. N. Silva ◽  
...  
Keyword(s):  
Bond Strength ◽  
Concrete Block ◽  
Tensile Bond Strength ◽  
Water Penetration ◽  
Strength Tests ◽  
Lime Solution ◽  
Concrete Blocks ◽  
Materials Used ◽  
Bonding Systems ◽  
Direct Tensile

The understanding of the mechanical fixation behavior of coatings is crucial for a better comprehension of the bonding systems, especially at the interface between the mortar and the substrate. Physical adherence is related, among other things, to the contents of the materials used in the roughcast and mortar coatings, due to the colloidal water penetration into the pores of the substrate. This work evaluated the influence of different lime solution additions replacing the kneading water in the preparation of roughcast and mortar coatings. Two types of substrates were investigated:ceramic bricks and concrete blocks. Three wall masonry panels were constructed, with dimensions of 220 × 180 cm2, one of concrete block and two of ceramic bricks, followed by the application of roughcast and mortar coating with an average thickness of 5 mm and 20 mm, respectively. Direct tensile bond strength tests were performed and the results, with a 95% confidence level, showed that substrate ceramic and treatment in the roughcast exhibited a better behavior regarding the distribution of the tensile bond strength of the tested specimens. However, no significant differences of the amount of addition used (0%, 5%, 10% and 15%) on the tensile bond strength were observed.

Mechanical Properties of Various Models of Interlocking Concrete Blocks under In-Plane and Out-of-Plane Loads

2021 ◽  
Vol 881 ◽  
pp. 149-156
Author(s):  
Mochamad Teguh ◽  
Novi Rahmayanti ◽  
Zakki Rizal
Keyword(s):  
Mechanical Properties ◽  
Building Material ◽  
Experimental Tests ◽  
Concrete Block ◽  
Masonry Wall ◽  
Masonry Walls ◽  
Plane Shear ◽  
Out Of Plane ◽  
Concrete Blocks ◽  
Local Materials

Building material innovations in various interlocking concrete block masonry from local materials to withstand lateral earthquake forces is an exciting issue in masonry wall research. The block hook has an advantage in the interlocking system's invention to withstand loads in the in-plane and out-of-plane orientations commonly required by the masonry walls against earthquake forces. Reviews of the investigation of in-plane and out-of-plane masonry walls have rarely been found in previous studies. In this paper, the results of a series of experimental tests with different interlocking models in resisting the simultaneous in-plane shear and out-of-plane bending actions on concrete blocks are presented. This paper presents a research investigation of various interlocking concrete blocks' mechanical properties with different hook thicknesses. Discussion of the trends mentioned above and their implications towards interlocking concrete block mechanical properties is provided.

Humidity Effects on Porous Silica Thin Films

1995 ◽  
Vol 411 ◽  
Author(s):  
J. R. Kokan ◽  
R. A. Gerhardt
Keyword(s):  
Thin Films ◽  
Ac Conductivity ◽  
Sol Gel ◽  
Porous Silica ◽  
Controlled Environment ◽  
Alkali Ions ◽  
Humidity Effects ◽  
Silica Thin Films ◽  
Environment Chamber ◽  
Humidity Sensitivity

ABSTRACTImpedance Spectroscopy is being used to study the humidity sensitivity of porous silica thin films. The films are processed via a colloidal sol-gel method which leaves some remnant potassium and sodium. Previous work on bulk porous silica samples processed by the same method showed that the dielectric properties and ac conductivity were very sensitive to changes in humidity. The aim of this work was to determine if the same dependencies could be found in the thin films. The capacitance, dielectric loss, and ac conductivity of the films were measured in a controlled environment chamber from 20–80% RH for frequencies ranging from 10Hz–10MHz. In addition to characterizing films with varying amounts of residual alkali ions obtained through leaching, we have also measured films that were surface doped with controlled amounts of KCl, LiCl, or NaCl. Relative humidity dependencies in the films are not as dramatic as in the bulk samples. The reasons for this behavior are not yet clear, but may be associated with the porosity, thickness, and surface area of the films.

scholarly journals Mechanical characterization of concrete block used on infill masonry panels

2018 ◽  
Vol 9 (3) ◽  
pp. 281-295 ◽  
Author(s):  
Patricia Raposo ◽  
André Furtado ◽  
António Arêde ◽  
Humberto Varum ◽  
Hugo Rodrigues
Keyword(s):  
Mechanical Characterization ◽  
Experimental Tests ◽  
Concrete Block ◽  
Masonry Walls ◽  
Compression Tests ◽  
Content Type ◽  
Average Resistance ◽  
Concrete Blocks ◽  
Simple Compression ◽  
Infill Masonry

Purpose The infill masonry walls in recent worldwide earthquakes have shown that it is necessary to conduct further studies to characterize the behavior of existing buildings and, in particular, of infill masonry walls under seismic activity. The lack of characterization studies of infill walls made by concrete blocks justifies the investigation reported herein, which includes experimental tests on sample sets to evaluate the mechanical properties of masonry components (units and mortar) and assemblages (wallets) made with masonry units from Faial. For the later, normal compressive, diagonal tensile/shear and out-of-plane flexural strengths were obtained according to standard procedures, the results of which are presented in the manuscript. The paper aims to discuss these issues. Design/methodology/approach One experimental campaign was conducted with the aim to mechanically characterize concrete blocks masonry samples. Several experimental tests were carried out in full-scale masonry concrete wallets according to the constructive methodology used. Findings Based on the data obtained from the mechanical characterization tests of the concrete masonry blocks, it can be seen that under simple compression, the masonry specimens’ average resistance is about 6 times superior than the average resistance to diagonal shear/tension, while the stiffness is almost doubled. In simple compression tests, it was observed that the masonry specimens cracked in areas of higher drilling of the blocks. In the tensile tests by diagonal compression, it was found that the test specimens were mainly fissured by the block/mortar joint interfaces, following the delineation of settlement and top joints. Originality/value There are no experimental results available in the literature for this type of bricks that can contribute to the development of numerical studies.

scholarly journals Energy efficient building envelope using waste PET in concrete

2020 ◽  
Vol 307 ◽  
pp. 01022
Author(s):  
Gitanjali Thakur ◽  
Mohamad Asalam ◽  
Mohammed El Ganaoui
Keyword(s):  
Thermal Conductivity ◽  
Energy Efficient ◽  
Chemical Resistance ◽  
Concrete Block ◽  
Building Envelope ◽  
Environmental Threat ◽  
Concrete Blocks ◽  
Global Threat ◽  
Partial Weight ◽  
Energy Efficient Building

One of the major environmental threat in the world today is the increased production of plastic and its usage. The inept plastic waste management system with regard to its recycling and energy recovery in the developing countries creates a global threat as a major land and water body pollutant. However, its durability, thermal properties, and chemical resistance make plastics an alternate choice as a building material. This study investigates the use of plastic in concrete mixture with an objective to improve the thermal performance of the building. The shredded plastic fibers from plastic bottles (polyethylene terephthalate, PET) were used as a partial weight replacement (2.5%, 5%, and 7.5%) of coarse aggregate in concrete blocks. The cubes were cast using the Indian standards (IS 456) and the essential tests were performed. Additionally, experiments were designed to investigate the change in the thermal conductivity of the concrete block due to the varying amount of plastic. It was found that the use of PETs affected the compressive strength and also decreased the thermal conductivity of the concrete blocks. The experimental results suggest that PETs can be used in the construction of energy-efficient building to handle the environmental concerns because of its abundance.

Performance Study on Masonries of Different Aerated Concrete Blocks

2014 ◽  
Vol 633 ◽  
pp. 299-302 ◽  
Author(s):  
Peng Fei Peng ◽  
Xian Ming Qin ◽  
Yu Sheng Wu
Keyword(s):  
Water Absorption ◽  
Natural Condition ◽  
Crack Width ◽  
Concrete Block ◽  
Performance Study ◽  
Shrinkage Cracking ◽  
Concrete Cracking ◽  
Concrete Masonry ◽  
Concrete Blocks ◽  
Aerated Concrete

The masonries with a square of 2m×3m of 3 different aerated concrete blocks were built respectively, and plastered with plastering mortar. The shrinkage-cracking property and other performances of different aerated concrete masonries were studied in natural condition. The results showed that, there were less cracks and smaller crack width in the masonry of aerated concrete with low water absorption, the condition of aerated concrete cracking can be improved by plastering with plastering mortar; the shrinkage of aerated concrete block masonry with low water absorption is smaller, the shrinkage of aerated concrete masonry plastered by special plastering mortar is smaller.

Rapid Prototyping of Full Scale House Structures

2011 ◽  
Author(s):  
Sangju Lee ◽  
Eberhard Bamberg ◽  
Charles Eason
Keyword(s):  
Compressive Strength ◽  
Rapid Prototyping ◽  
Construction Material ◽  
Construction Materials ◽  
Full Scale ◽  
Good Surface ◽  
Concrete Blocks ◽  
Good Surface Finish ◽  
Aerated Concrete ◽  
Cutting Speeds

This paper reports on the machining of a construction material (aerated concrete) with a rapid prototyping device, Shapemaker III, which is based on waterjet technology. Preliminary machining tests were carried out to investigate machining conditions (speed and pressure) of separation cuts. Cutting speeds for the waterjet were investigated for two aerated concrete construction materials; autoclaved aerated concrete (AAC) in two strengths (348 and 580 psi compressive strength) and a non-autoclaved, fiber reinforced aerated concrete (FRAC) with a 450 psi compressive strength. Cutting samples were prepared in four thicknesses (0.5, 1, 2, and 3 inches) and cut at two pressures (40 and 60 ksi). The 0.5 and 1 inch specimens were cut with good surface finish at over 600 in/min at 40 ksi. The 2 and 3 inch specimens could be cut at 320 and 80 in/min at 40 ksi, respectively. The experimental data was used in the fabrication of rapid prototyping houses with a pure waterjet machine. As results, full scale houses were fabricated with FRAC and Styrofoam. Additionally, a sub-mold of an outdoor fireplace was manufactured with Styrofoam for casting of customized aerated concrete blocks.

Preparation of TiO2 and SiO2 Nanoparticles and their Effect on Epoxy Resin Nanocomposites

2020 ◽  
Vol 12 (2) ◽  
pp. 135-141
Author(s):  
Gagi Tauhidur Rahman ◽  
Moumita Tasnim Meem ◽  
Md. Abdul Gafur ◽  
Abu Mahmud ◽  
Md. Asadul Hoque
Keyword(s):  
Polymer Matrix ◽  
Epoxy Matrix ◽  
Sol Gel ◽  
Sio2 Nanoparticles ◽  
Silica Sand ◽  
Epoxy Nanocomposites ◽  
Nano Sio2 ◽  
Sem Image ◽  
Comparable Performance ◽  
Xrd Patterns

Background: Polymer matrix-based composites are the workhorse of the composite industries. Besides, the idea of modifying the polymer matrix by various inorganic fillers has greatly drawn the attention of materials engineers due to their diversified applications and advanced properties. Objective: The objective of this work was to prepare and characterize Titania (TiO2) and Silica (SiO2) nanoparticles and develop 1wt%, 3wt%, 5wt% and 10wt% TiO2 and SiO2 incorporated epoxy-based nanocomposites. Here, we used TiO2 incorporated epoxy composites as a model to compare the effectiveness and contribution of locally available nano SiO2 in the epoxy matrix. Method: The TiO2 nanoparticles were prepared by most famous and conventional sol-gel method and SiO2 nanoparticles were extracted from Padma river (silica) sand obtained from Rajshahi city, Bangladesh from a very easy and inexpensive route. Both TiO2/epoxy and SiO2/epoxy nanocomposites (approximately 1.3-1.5 mm thick) were prepared via a solution casting method incorporating the TiO2 and SiO2 nanofillers in the epoxy matrix. Results: The XRD patterns and SEM image ensure the formation of TiO2 and SiO2 nanoparticles. A number of tests reveal that mechanical properties especially hardness and young’s modulus of the nanocomposites have increased while decreasing the tensile and flexural strength than neat epoxy due to the incorporation of nanofiller. It is visible that, TiO2/epoxy nanocomposites have shown better performance than the virgin epoxy but surprisingly in most cases, nano SiO2 exhibited comparable and even better contribution than TiO2/epoxy nanocomposites. This indicates that the use of TiO2 in epoxy might be replaced by inexpensive nano SiO2 to be used in various structural sectors. Conclusion: The TiO2 and SiO2 nanoparticles were synthesized successfully. The preliminary experiments predict that the addition of nanoparticles (TiO2, SiO2) converts the composite from being ductile into a brittle material where SiO2/epoxy shows comparable performance with TiO2/epoxy nanocomposites.

Thermo-Physical Behaviour and Mechanical Properties of Experimentally Enhanced Rubberised Concrete Block

2014 ◽  
Vol 925 ◽  
pp. 169-174
Author(s):  
Khalid B. Najim ◽  
Ibrahim A. Al-Jumaily
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Concrete Block ◽  
Crumb Rubber ◽  
Concrete Wall ◽  
Normal Concrete ◽  
Physical Behaviour ◽  
Concrete Blocks ◽  
Rubber Concrete

The aim of the presented study is to investigate the thermo-physical behaviour and mechanical properties of mortar pre-coated crumb rubber concrete block. For this purpose, thermal conductivity, emissivity and effusively will be tested in addition to the specific heat capacity. Thereafter, dynamic calculator software will be used to study the behaviour of a wall that constructed using the suggested concrete block and a comparison with a normal concrete wall will be made. Compressive, splitting tensile and flexural strength were tested as well. The results show that concrete blocks which meet the requirement of strength can be produced with about 300 kg/m3 of crumb rubber aggregate.

Characterization of a Limestone Powder Residue for Recycling as a Concrete Block Incorporation

2014 ◽  
Vol 798-799 ◽  
pp. 3-8 ◽  
Author(s):  
Jonas Alexandre ◽  
Afonso Rangel Garcez de Azevedo ◽  
Gustavo de Castro Xavier ◽  
Leonardo Gonçalves Pedroti ◽  
Carlos Maurício Fontes Vieira ◽  
...  
Keyword(s):  
Chemical Analysis ◽  
Physical Properties ◽  
Construction Material ◽  
Concrete Block ◽  
Limestone Powder ◽  
Small Particles ◽  
Microstructural Characteristics ◽  
Physical Chemical ◽  
Concrete Blocks

The mining and processing of limestone in the state of Rio de Janeiro, southeast of Brazil, generates a considerable amount of small particles, like a powder ,which is commercialized as a by product. In principle, this inert limestone powder could be recycled as part of another civil construction material. Thus, the objective of this work was to characterize a limestone powder by its physical properties, chemical analysis and microstructural aspects. The results were compared with the characteristics of a common cement and a conventional sand to be possibly applied in the fabrication of limestone incorporated concrete blocks. It was found that the limestone powder has physical, chemical and microstructural characteristics satisfactory for concrete blocks incorporation.

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