scholarly journals EXPERIMENTAL RESEARCH OF PRECAST CONCRETE FLOOR BLOCKS WITH IMPROVED RESISTANCE TO HIGH TEMPERATURE

2016 ◽  
Author(s):  
Dubravka Bjegovic ◽  
Ivana Miličevic ◽  
Nina Štirmer
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Precast Concrete ◽  
Partial Replacement ◽  
Concrete Floor ◽  
Clay Bricks ◽  
Natural Aggregate ◽  
Floor Systems ◽  
Concrete Blocks ◽  
Crushed Brick

The paper presents possibility of usage of crushed clay bricks and roof tiles as an aggregate for concrete in precast concrete floor blocks. According to literature review, concrete with crushed brick and roof tiles as an aggregate has better thermal properties than regular concrete with natural aggregate. Applicability of concrete mixture for precast concrete blocks was tested regarding the requirements set in HRN EN 15037-2 Precast Concrete products – Beam and block floor systems – Part 2: Concrete blocks. Precast concrete blocks with crushed bricks and roof tiles were made and their mechanical properties after exposure to high temperature were tested. Based on experimental results, conclusions are made about usage of crushed bricks and roof tiles as partial replacement of natural aggregate in concrete for precast concrete blocks with improved resistance to high temperatures.

scholarly journals Estudo da produção de pavers para pisos intertravados utilizando resíduos de blocos de concreto

2021 ◽  
Vol 42 (1) ◽  
pp. 21
Author(s):  
Vasni Oliveira da Silva Junior ◽  
Victor Mateus Pavão ◽  
André Camacho Pontremolez ◽  
Bruno de Medeiros Costa ◽  
Gerson Cendes Saragosa ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Precast Concrete ◽  
Physical And Mechanical Properties ◽  
Raw Material ◽  
Technical Knowledge ◽  
Concrete Blocks

This work presents part of a study whose main objective is to observe the behavior of the physical and mechanical properties of the materials (raw material) and of products made for the civil construction from the precast concrete industry, such as concrete blocks and pavers for interlocking floors. Through the investigation, was identified the potential of using the concrete blocks waste of the production as aggregates added to the concretes utilized to produce pavers. Thus, it is expected that this work contributes as a basis for obtaining scientific and technical knowledge regarding the materials and procedures that must be adopted for the manufacture of pavers, allowing their production for commercialization.

Performance of precast concrete floor systems during the 2010/2011 Canterbury earthquake series

2014 ◽  
Vol 66 (11) ◽  
pp. 563-575 ◽  
Author(s):  
Samuel Robert Corney ◽  
Richard Stuart Henry ◽  
Jason Maxwell Ingham
Keyword(s):  
Precast Concrete ◽  
Concrete Floor ◽  
Earthquake Series ◽  
Floor Systems

scholarly journals Evaluation of using crushed brick as coarse aggregate in concrete layer within rigid highway pavement

2018 ◽  
Vol 162 ◽  
pp. 01045
Author(s):  
Ali Alwash ◽  
Fatimah Al-Khafaji
Keyword(s):  
Coarse Aggregate ◽  
Partial Replacement ◽  
Experimental Investigations ◽  
Construction Technique ◽  
Rigid Pavement ◽  
Clay Bricks ◽  
Concrete Layer ◽  
Concrete Mix ◽  
Crushed Brick ◽  
Highway Pavement

Most of the present studies related to the field of highway pavement construction technique tend to make use of the local available materials as substitutes for the imported and necessary materials for some of the practical application. For this reason this research aims at looking for the prospect of used locally available aggregate such as crushed clay bricks for the aim of producing proper concrete with suitable thermal and mechanical properties. Experimental investigations have been carried out to asses the effect of partial replacement of coarse aggregate by free manually crushed Brick with percentages (10, 20, 30 and 40)% of virgin coarse aggregate in concrete mix for highway rigid pavement. While the percentage (0)% replacement represent reference mix. Mix proportion based on the target of compressive strength for all replacement percentage of (33) MPa at (28) days to achieve AASHTO requirement for highway concrete rigid pavement .The results of flexural strength, modulus of elasticity, density and thermal conductivity refers to better performance (less thickness of concrete layer with large spacing between contraction or expansion joints and less stresses due to warping induced concrete layer) for concrete mix with 20% crushed brick as replacement of coarse aggregate.

scholarly journals Effect of high temperature and type of cooling on some mechanical properties of cement mortar

2018 ◽  
Vol 162 ◽  
pp. 02010
Author(s):  
Faisal Abdulhussei ◽  
Waleed Abbas ◽  
Qais Frayyeh
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Flexural Strength ◽  
Cement Mortar ◽  
Construction Materials ◽  
Air Cooling ◽  
Water Cooling ◽  
Crushed Brick

Mortar of cement as construction materials subjected sometimes to high temperature. Some of properties of this mortar being studied after this effect. The effect of high temperature 100, 200, 400 and 700°C (exposed for two hrs.) on some mechanical properties (compressive and flexural strength) of two groups of cement mortar samples (with and without the addition of crushed bricks and superplasticizer as modifying materials) has been studied. Two methods of cooling samples by air and by water for 1/2 hr. was used, then tested after 3, 7 and 28 days. The results showed that the compressive and flexural strength for reference mix exposed to 700°C and water cooling decreased by 65.3 % and 64.7%, respectively, compared with their reference mix tested at 20°C in 28 days. While mixes containing 100% of crushed brick as an additive and air cooling decreases by 12.3% and 9% of their compressive and flexural strength, respectively compared with the mixes tested at 20°C in 28 days. Also showed that the decreases in flexural strength for no sand mixes containing 100% of crushed brick and 4% of superplasticizer exposed to 700°C and then water cooling was 28.2% compared to those for reference mixes tested at 20°C.

Effects of corrosion on the behaviour of precast concrete floor systems

2017 ◽  
Vol 145 ◽  
pp. 411-418 ◽  
Author(s):  
Eduardo S. Cavaco ◽  
Afonso Bastos ◽  
Filipe Santos
Keyword(s):  
Precast Concrete ◽  
Concrete Floor ◽  
Floor Systems

Influence of Selected Pozzolanas on Basic Physical and Mechanical Properties of HSC

2015 ◽  
Vol 824 ◽  
pp. 39-42
Author(s):  
Eva Vejmelková ◽  
Monika Čáchová ◽  
Jaroslava Koťátková
Keyword(s):  
Mechanical Properties ◽  
High Strength Concrete ◽  
Physical And Mechanical Properties ◽  
High Strength ◽  
Partial Replacement ◽  
Replacement Level ◽  
Matrix Density ◽  
The Subject ◽  
Crushed Brick ◽  
Reference Mixture

Crushed brick (CB) used in high strength concrete as partial replacement of cement is the subject of this paper. It is a waste material and so its exploitation is needed to be found. Concrete industry can be proper area as CB is a fine material and is pozzolanic active. Basic physical properties and mechanical properties were investigated. Open porosity and bulk density achieved the best values when 30% of cement was replaced by CB. Matrix density decreased with rising addition ratio. The values of compressive strength was the highest for 30% replacement level and with 60% addition ratio were not lower than for the reference mixture. The conclusion is, that according to studied parameters 30% of cement substituted by CB is the most profitable addition ratio.

scholarly journals Use of Prefabrication, Construction and Demolition Wastes as an Aggregate in Vibropressed Precast Concrete Blocks Production

2022 ◽  
Vol 11 (1) ◽  
pp. 20-28
Author(s):  
Grzegorz Łój ◽  
Wiesława Nocuń-Wczelik
Keyword(s):  
Precast Concrete ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Partial Substitution ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Concrete Technology ◽  
Natural Sand ◽  
Natural Aggregate ◽  
Concrete Blocks

The aim of current study was to determine the recycled concrete aggregate (RCA) applicability in the production of concrete mixture for vibropressed concrete blocks. The experiments were focused especially on the crushed waste material from the same concrete elements producing plant.  For this type of precast elements only some finer fractions can be implemented and the “earth-moist” consistency of fresh mixture is required. The series of samples was prepared in which the mixture of natural aggregates was partially or totally substituted by recycled concrete aggregate. The 0/4 RCA fraction, which is usually rejected in ready mix concrete technology, plays a role of 0/2 sand.  The substitution of sand fraction was from 20% to 100% respectively. The substitution of the coarser aggregate fractions by 4/16 RCA was also done. The standard properties of vibropressed elements, such as the degree of densification, the density of material, the compressive and splitting tensile strength and the water absorption capacity according to the relevant standards were determined. The parameters of materials with the natural aggregate substitution by RCA are affected by the ratio of recycled concrete aggregate. In most cases the results do not decline specially from those for reference samples, when only the natural sand (0/2) fraction is substituted by the 0/4 recycled aggregate. As one could expect, as lower the substitution, as better the test results. The partial substitution of natural aggregate by coarser fractions requires experimental verification; over 20% substitution of natural aggregate by 4/8, 8/16 or 0/16 RCA should be excluded.

Lattice Imaging of Grain Boundaries in Ceramics

1977 ◽  
Vol 35 ◽  
pp. 114-115
Author(s):  
D. R. Clarke ◽  
G. Thomas
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Grain Boundaries ◽  
High Temperature Strength ◽  
Current Interest ◽  
Lattice Imaging ◽  
Special Significance ◽  
Structural Applications ◽  
Refractory Ceramics

Grain boundaries have long held a special significance to ceramicists. In part, this has been because it has been impossible until now to actually observe the boundaries themselves. Just as important, however, is the fact that the grain boundaries and their environs have a determing influence on both the mechanisms by which powder compaction occurs during fabrication, and on the overall mechanical properties of the material. One area where the grain boundary plays a particularly important role is in the high temperature strength of hot-pressed ceramics. This is a subject of current interest as extensive efforts are being made to develop ceramics, such as silicon nitride alloys, for high temperature structural applications. In this presentation we describe how the techniques of lattice fringe imaging have made it possible to study the grain boundaries in a number of refractory ceramics, and illustrate some of the findings.

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