THIN LAYER CONCRETE BLOCKWORK IN COMPRESSION: AN EXPERIMENTAL ANALYSIS

2015 ◽  
Vol 7 (2) ◽  
pp. 91-96 ◽  
Author(s):  
Ayman Trad ◽  
Hassan Ghanem ◽  
Nivine Abbas ◽  
Ziad Hamdan
Keyword(s):  
Compressive Strength ◽  
Research Program ◽  
Concrete Block ◽  
Thin Layers ◽  
Lightweight Aggregates ◽  
Masonry Construction ◽  
Concrete Masonry ◽  
Concrete Blocks ◽  
Compressive Strength Of Concrete ◽  
Set Up

The compressive strength of concrete block masonry is dependent upon the unit compressive strength, the type of unit, the mortar and the form of masonry construction (Mirza et al. 1995). The design codes allow masonry compressive strength to be established (or better: estimated) by calculation, from tests, or from tabulated values. In this way the current European masonry standard EN 1996: Part 1-1 (LST EN 1996-1-1) tabulates the masonry strength for concrete blocks with thin layers of mortar. In France, doubts exist on the validity of these tabulated values for the blocks made with lightweight aggregates. To provide data for an extension of the use of the tabulated values for lightweight aggregates blocks and at the same time to provide input to the development of Eurocode 6, a major research program was set up. The research program aims to evaluate the mechanical strength of the thin joints hollow concrete masonry made with dense or lightweight aggregates. Tests have been carried out on a very large type of hollow blocks. Different geometries of blocks and different types of aggregates are tested. All these tests are based on CEN standards to meet Eurocode 6 requirements. This work proves that the formula proposed by Eurocode 6 to calculate the characteristic compressive strength of hollow concrete masonry are largely safe. It was also found that the strength of masonry depends only on the block resistance and is independent of the nature of aggregate.

scholarly journals Study of brazilian structural concrete block conformity

2018 ◽  
Vol 11 (4) ◽  
pp. 652-672
Author(s):  
W. C. SANTIAGO ◽  
A. T. BECK
Keyword(s):  
Compressive Strength ◽  
Dimensional Analysis ◽  
Concrete Block ◽  
Structural Concrete ◽  
Class A ◽  
Masonry Construction ◽  
Strength Tests ◽  
Concrete Blocks

Abstract This paper presents a study of the conformity of structural concrete blocks manufactured and used in masonry construction in Brazil. It is based on compressive strength tests, on dimensional analysis and absorption tests of over six thousand samples from three classes (A, B and C) and two modular sizes (M-15 and M-20). National results show that blocks tend to have an estimated compressive strength higher than specified, except blocks from class A. Regional results show that blocks manufactured in the northeast (NE) are consistently non-conforming, for all block classes. The study also shows that dimensional variations and absorption tests results are within code tolerances.

scholarly journals Humidity and specimen preparation procedure: influence on compressive strength of concrete blocks

2021 ◽  
Vol 14 (2) ◽  
Author(s):  
Guilherme Aris Parsekian ◽  
André Luis Christoforo ◽  
Amanda Duarte Escobal Mazzú ◽  
Gláucia Maria Dalfré
Keyword(s):  
Compressive Strength ◽  
Concrete Block ◽  
Block Type ◽  
Specimen Preparation ◽  
Standard Procedures ◽  
Strength Tests ◽  
Concrete Blocks ◽  
Compressive Strength Of Concrete ◽  
Average Block ◽  
Best Fit

abstract: It is extremely important that the quality control of the concrete block used in structural masonry is conducted based on standard procedures that allow reliable estimation of the properties of these components. This work aims to analyze and evaluate the influence of the concrete block moisture on the result of the compression test. Hollow concrete blocks were prepared and subsequently maintained in different environments for various periods of time and under different conditions of temperature and humidity to determine the influence of the type of drying on the relative humidity of the block at the time of testing and consequently on its compressive strength. As a conclusion, it can be stated that, because it is necessary to use water in the process, the grinding rectification of the faces of the blocks led them to have high humidity, above 70%. If tested in this condition, the results of the compressive strength tests will be lower than that of blocks under usual environmental conditions. No differences were found in the average block strength when they were kept dry in the controlled environment of the laboratory during periods of 24 or 48 h. After grinding, it is not necessary to dry the blocks inside an oven at 40ºC before the tests; simply leaving them at a usual room temperature of 23ºC and humidity of 40 ± 5% for 24h is sufficient. The attempt to accelerate drying in an oven at 100ºC is not adequate because this leads to an increase in the compressive strength. From the results, it was possible to determine expressions to correlate the compressive strength as a function of the moisture of the block at the time of the test. The best-fit expressions are distinct for each block type, but the formulations are consistent in indicating a considerable difference in resistance as a function of moisture.

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 Compressive strength of masonry constructed with high strength concrete blocks

2017 ◽  
Vol 10 (6) ◽  
pp. 1273-1319 ◽  
Author(s):  
E. S. FORTES ◽  
G. A. PARSEKIAN ◽  
J. S. CAMACHO ◽  
F. S. FONSECA
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
Strain Curve ◽  
High Strength ◽  
Masonry Walls ◽  
Strength Ratio ◽  
Stress Strain Curve ◽  
Strength Concrete ◽  
Concrete Masonry ◽  
Concrete Blocks

Abstract Although the use of high strength concrete blocks for the construction of tall buildings is becoming common in Brazil, their mechanical properties and behavior are not fully understood. The literature shows a gap in experimental studies with the use of high strength concrete blocks, i.e., those with compressive strength greater than 16 MPa. The work presented herein was conducted in order to study the behavior of high strength structural masonry. Therefore, the compressive strength and modulus of elasticity of concrete block walls tested under axial load were assessed. The specimens included grouted and ungrouted walls and walls with a mid-height bond beam; ungrouted walls were constructed with face-shell and full mortar bedding. The walls were built and tested in the laboratory of CESP and in the Structures Laboratory of the UNESP Civil Engineering Department in Ilha Solteira (NEPAE). Concrete blocks with nominal compressive strength of 16 (B1), 24 (B2) and 30 (B3) MPa were used. Ungrouted masonry walls had a height of 220 cm and a width of 120 cm while grouted masonry walls had a height of 220 cm and a width of 80 cm. Traditional Portland cement, sand and lime mortar was used. The testing program included 36 blocks, 18 prisms, 9 ungrouted walls (6 with face-shell mortar bedding and 3 with full mortar bedding), 9 grouted masonry walls, and 12 ungrouted walls with a bond beam at mid-height. The experimental results were used to determine the compressive strength ratio between masonry units, prisms and masonry walls. The analyses included assessing the cracking pattern, the mode of failure and the stress-strain curve of the masonry walls. Tests results indicate that the prism-to-unit strength ratio varies according to the block strength; that face-shell mortar bedding is suitable for high strength concrete masonry; and that 20% resistance decrease for face-shell mortar bedding when compared with full mortar bedding is a conservative consideration. The results also show that using a bond beam at the mid-height of the wall does not lead to a compressive strength decreased but it changes the failure mode and the shape of the stress-strain curve. In addition, the results show that estimating E = 800 fp is conservative for ungrouted masonry walls but reasonably accurate for grouted masonry walls and that there is no reason to limit the value of E to a maximum value of 16 GPa. Furthermore, the results show that, for design purposes, a wall-to-prism strength ratio value of 0.7 may be used for high strength concrete masonry.

NUMERICAL AND EXPERIMENTAL ANALYSIS OF GROUTED HOLLOW BLOCK MASONRY UNDER COMPRESSION / BLOKŲ SU BETONU UŽPILDYTOMIS TUŠTYMĖMIS GNIUŽDOMOJO MŪRO ĮTEMPIŲ BŪVIO SKAITINĖ IR EKSPERIMENTINĖ ANALIZĖ

2013 ◽  
Vol 5 (2) ◽  
pp. 45-53 ◽  
Author(s):  
Robertas Zavalis ◽  
Bronius Jonaitis ◽  
Gediminas Marčiukaitis
Keyword(s):  
Compressive Strength ◽  
Experimental Analysis ◽  
Initial Stresses ◽  
Sound Insulation ◽  
Masonry Construction ◽  
Concrete Blocks ◽  
Hollow Block ◽  
Overall Performance ◽  
Masonry Units

Highly hollow masonry units, which allow reducing the weight of masonry constructions and improving heat and sound insulation qualities, are commonly used in masonry construction. Filling the hollows with concrete, or concrete with light additives, results in complex masonry. Overall performance of such masonry is affected by initial stresses, which are caused by shrinkage deformations of different infill concrete and masonry units. Behaviour of infill concrete and concrete blocks is analysed by applying numerical detailed micro modelling. Experiments revealed that masonry deformations of blocks with concrete filled hollows are similar to those of longitudinal deformations of infill concrete samples. σ-ε relations were received through numerical micro modelling and compressive strength of masonry match values were estimated during experiments. Santrauka Straipsnyje pateikiama betoninių blokų su betonu užpildytomis tuštymėmis gniuždomojo mūro įtempių būvio analizė. Mechaninėms tokio mūro savybėms įtakos turi pradiniai įtempiai, kuriuos sukelia skirtingos užpildymo betonu ir mūro gaminių traukiosios deformacijos. Užpildymo betono ir betoninių blokų elgsena analizuojama taikant tikslų skaitinį mikromodeliavimą. Eksperimentais nustatyta, kad blokų su užpildytomis betonu tuštymėmis mūro deformacijos artimos užpildymo betono deformacijoms. Skaitiniu modeliavimu gautos σ-ε priklausomybės ir gniuždomasis mūro stipris gerai sutampa su eksperimentais nustatytomis reikšmėmis.

scholarly journals Mechanical Properties of Concrete and Hollow Concrete Blocks Containing Steel and Nylon Fibres

2019 ◽  
Vol 8 (6) ◽  
pp. 3162-3168
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Steel Fibre ◽  
Concrete Block ◽  
Concrete Mix ◽  
Different Types ◽  
Concrete Blocks ◽  
Nylon Fibre ◽  
Strength Improvement

An attempt has been made in this paper to study the effect on the mechanical properties of the concrete and hollow concrete block when different types of fibres were added to the mix. The two different types of fibres added include Steel fibres with hooked end and of length 60mm at five different fibre ratios of 2.5%, 2.75%, 3.0%, 3.25% and 3.5% and Nylon fibres having a length of 18mm at the content of 0.5%, 0.75%, 1.0%, 1.25% and 1.50%. The concept of fibre hybridization was also analyzed and the effect was studied by preparing concrete mix with various percentage combinations of steel and nylon fibres at a total fibre ratio of 3% by weight of cement. The investigation focused on finding the optimum values of fibres to be added and also carried out the compressive strength and tensile strength of concrete with and without fibres. The compressive strength of hollow concrete blocks made with and without fibres was also analyzed. The samples of concrete and hollow concrete blocks were cast and immersed in water for a curing period of 28 days. The results on strength of fibre added concrete and hollow concrete block obtained was compared with the control mix result and the study concludes that the steel fibre and nylon fibre added concrete and hollow concrete block showed an improvement in the mechanical properties for each fibre ratio considered. Out of the various combinations of steel and nylon fibre tried, the best compressive strength improvement was exhibited by the concrete mix with 3% of the steel fibre without any addition of nylon fibres while the best tensile strength improvement was shown by the concrete mix with 2.25% of steel fibre and 0.75% of nylon fibre.

scholarly journals EXPERIMENTAL INVESTIGATION OF MECHANICAL PROPERTIES OF SOLID CONCRETE BLOCK MASONRY EMPLOYING DIFFERENT MORTAR RATIOS

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Muhammad Rizwan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Shear Strength ◽  
Research Work ◽  
Concrete Block ◽  
Unit Weight ◽  
Three Samples ◽  
Individual Unit ◽  
Concrete Blocks

This research work aims to investigate experimentally the mechanical properties of solid concrete blocks as an individual unit and assembly (block masonry) employing different mortar mix ratios. The material properties of the concrete block unit, such as compressive strength and unit weight were explored by taking three samples from the four local factories. The block masonry assemblages were subjected to various load patterns for the evaluation of compressive strength, diagonal tensile strength and shear strength. For the bond, four types of mortars i.e., cement – sand (1:4), cement – sand (1:8), cement – sand – khaka (1:2:2) and cement – sand – khaka (1:4:4) were used in the joints of concrete block masonry assemblages. (Khaka is a by-product formed in the stone crushing process). For each type of mortar, three samples of block masonry were fabricated for compressive strength, shear strength and diagonal tensile strength, and tested in the laboratory. It is observed that the replacement of sand by khaka enhanced the mechanical properties of masonry.

Effect of Dimensions on the Compressive Strength of Concrete Masonry Prisms

2015 ◽  
Vol 4 (1) ◽  
pp. 20150001 ◽  
Author(s):  
Reza Hassanli ◽  
Mohamed A. ElGawady ◽  
Julie E. Mills
Keyword(s):  
Compressive Strength ◽  
Concrete Masonry ◽  
Compressive Strength Of Concrete
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