scholarly journals Incipient motion of Armorflex articulating concrete blocks on steep slopes

2021 ◽  
Vol 63 (3) ◽  
pp. 1-15
Author(s):  
K Delport ◽  
G R Basson ◽  
A Bosman
Keyword(s):  
South African ◽  
Concrete Block ◽  
Hydraulic Testing ◽  
Design Guidelines ◽  
National Standards ◽  
Protection Measure ◽  
Lack Of Information ◽  
Block Movement ◽  
Concrete Blocks ◽  
Steep Slopes

Armorflex is an articulating concrete block erosion protection measure that has been used as an alternative to riprap for many years. Even though extensive research and hydraulic testing have been conducted on Armorflex, the principal constraint on the use of concrete blocks has been the lack of information on prototype performance. Furthermore, there are no standards for Armorflex or articulating concrete block revetments in the South African National Standards, and design guidelines from Armorflex manufacturers are insufficient. The aim of this study was to improve the understanding of the critical flow conditions under which Armorflex blocks are lifted and removed by flowing water in open channel flow applications. Scaled laboratory tests were conducted on Armorflex 140 and Armorflex 180 blocks. Liu's theory of 1957 is applied in an attempt to define the point where block movement is initiated.

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.

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.

The Impact of Quality Standards on the Business Performance of Small, Medium and Micro-Sized Enterprises in Kwazulu-Natal: Selected Cases in the Durban Metropolitan Area

2021 ◽  
Author(s):  
Phindile B. Chili ◽  
Noluthando S. Matsiliza
Keyword(s):  
Quality Management ◽  
Small Business ◽  
South African ◽  
Business Performance ◽  
Quality Standards ◽  
National Standards ◽  
Management Systems ◽  
The South ◽  
Quality Management Systems ◽  
Small Business Performance

In the last decade, scholars showed an interest in alluding to compliance as a necessity to support small business performance in the last decades. Over the years, organisations have been frequently criticised for failing to comply with the quality standards such as the South African National Standards (SANS) 9001/ISO 9001 require effective implementation of Quality Management Systems and SANS 342, which provides specifications for diesel fuel products. Quality standards matrix adopted by the South African Bureau of Standards (SABS) is frequently used as a set of detailed specifications, requirements, various guidelines and characteristics to assure that the product, service or process is fit for purpose. Even though public and semi-autonomous institutions understand the value of subscribing and complying with quality standards, there is still a gap in the literature regarding the enforcement and compliance of quality standards in small business practices. There is a relationship between the adoption of quality standards and business excellence. Government can tap on the competitiveness of small, medium and micro-sized enterprises (SMMEs) and address their challenges and barriers that limit SMMEs to acquisition and compliance of statutory quality management systems.

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.

scholarly journals Assessment of Standards and Codes Dedicated to CFRP Confinement of RC Columns

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2390 ◽  
Author(s):  
Stefan Kaeseberg ◽  
Dennis Messerer ◽  
Klaus Holschemacher
Keyword(s):  
Reinforced Concrete ◽  
Cross Sections ◽  
Rupture Strength ◽  
Axial Strain ◽  
Design Guidelines ◽  
International Standards ◽  
National Standards ◽  
Rc Columns ◽  
New Findings ◽  
Cfrp Confinement

Reinforced concrete (RC) columns are often placed under confinement to increase their strength and ductility. Carbon fiber reinforced polymer (CFRP) materials have recently been recognized as favorable confinement systems. At present, a number of national standards and codes dedicated to the design of concrete components strengthened with CFRP in general and CFRP confinement in particular are available. These sets of rules provide design equations for confined reinforced concrete columns with circular and rectangular cross sections. Most of the standards and codes exhibit significant differences, including the used predictive models, limitations, observed effects and covered loading conditions. In this paper, five international standards and design guidelines are introduced and discussed. The purpose is to present a constructive and critical assessment of the state-of-the-art design methodologies available for CFRP confined RC columns and to discuss effects not previously considered properly. Therefore, some recent research efforts and findings from the Leipzig University of Applied Sciences are also introduced. The obtained data is used for a comparative study of the guideline predictive equations. Furthermore, it is shown that some new findings concerning the rupture strength and the maximum strength plus accompanying axial strain of a CFRP confined column are suitable to improve the current guidelines.

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.

Study on the Drafting and Early-Warning of Temperature Double-Control Index of Different Sections & Periods of Concrete Block

2012 ◽  
Vol 188 ◽  
pp. 253-258
Author(s):  
Dong Sheng Shen ◽  
Yao Ying Huang ◽  
Yi Hong Zhou ◽  
Dan Dan Liu ◽  
Xiang Ze Gao
Keyword(s):  
Prediction Model ◽  
Probabilistic Method ◽  
Concrete Block ◽  
Arch Dam ◽  
Maximum Temperature ◽  
Measured Temperature ◽  
Dynamic Feedback ◽  
High Arch Dam ◽  
Concrete Blocks ◽  
Real Time Tracking

Although real-time tracking and feedback were carried out for the dam concrete construction process, there was still certain blindness in the construction units. The temperature double-control index, which is the allowable temperature and temperature gradient under typical age before concrete block reaching its maximum temperature, was proposed in this paper on the basis of the analysis of measured temperature process curves of concrete blocks. The probabilistic method was applied to draft the temperature double-control index of different sections and periods based on the measured temperature process curve of the poured block of a constructing extra-high arch dam in southwest China. Furthermore, the prediction model was also provided and applied in the dynamic feedback of new pouring block. It is demonstrated by the practice that the prediction model proposed in this paper has better pertinence and maneuverability for the construction units to control the maximum temperature of concrete block, i.e. the maximum temperature in high temperature season and in low temperature season are both controllable.

Sign in / Sign up

Export Citation Format

Share Document