USAGE OF CALCIUM CARBONATE BIODEPOSITION IN MODIFICATION OF CEMENTITIOUS COMPOSITES

2018 ◽  
Vol 172 (52) ◽  
pp. 11-22
Author(s):  
Daniel Zawal ◽  
Krzysztof Górski ◽  
Agnieszka Dobosz
Keyword(s):  
Compressive Strength ◽  
Calcium Carbonate ◽  
Construction Materials ◽  
The Other ◽  
Cementitious Composites ◽  
Historic Buildings ◽  
Effective Solution ◽  
Other Hand ◽  
Compressive Strength Of Concrete ◽  
Durability Of Concrete

Biodeterioration of construction materials is an undesired phenomenon, generating high costs of constraction repairs. On the other hand, occurrence of some bacteria can affect prevention and self repair of fractures formed in concrete. Biodeposition is an effective solution for increasing compressive strength of concrete, extending durability of concrete constructions and renovating limestone elements in facades of historic buildings.

Effects of 0-30% Wood Ashes as a Substitute of Cement on the Strength of Concretes

2022 ◽  
Author(s):  
Theodore Gautier Bikoko ◽  
Jean Claude Tchamba ◽  
Valentine Yato Katte ◽  
Divine Kum Deh
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Greenhouse Gases ◽  
Negative Influence ◽  
Wood Ash ◽  
The Other ◽  
Other Hand ◽  
Strength Tests ◽  
Compressive Strength Of Concrete ◽  
Curing Age

To fight against the high cost and the increasing scarcity of cement and at the same time to reduce the CO2 greenhouse gases emission associated with the production of Portland cement, two types of wood ashes as a substitute of cement in the production of concretes were investigated. In this paper, we substituted cement by two types of species of wood ashes namely, avocado and eucalyptus ashes following the proportions ranging from 0% to 30 % on one hand, and on the other hand, we added these two types of species of wood ashes namely, avocado and eucalyptus ashes following the proportions ranging from 0% to 10 % by weight of cement in the concrete samples. After 7, 14 and 28 days of curing, compressive strength tests were conducted on these concrete samples. The findings revealed that using wood ashes as additives/admixtures or as a substitute of cement in the production/manufacturing of concrete decreased the compressive strength of concrete. Hence, it can be said that wood ash has a negative influence on the strength of concrete. At three percent (3%) and ten percent (10%) of addition, the wood ash from eucalyptus specie offers better resistance compared to the wood ash from avocado specie, whereas at five percent (5%) of addition, the wood ash from avocado specie offers better resistance compared to the wood ash from eucalyptus specie. At thirty percent (30%) of substitution, the wood ash from eucalyptus specie offers better resistance compared to the wood ash from avocado specie. The compressive strengths increase with the increase of curing age.

Effects of Concrete Compositions on the Elastic Modulus

2021 ◽  
Vol 322 ◽  
pp. 41-47
Author(s):  
Rudolf Hela ◽  
Lenka Bodnárová ◽  
Klára Křížová
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Negative Impact ◽  
The Other ◽  
Technological Factors ◽  
Factors Influencing ◽  
Other Hand ◽  
Eurocode 2 ◽  
Compressive Strength Of Concrete ◽  
Reducing Costs

The paper comments on the influence of various technological factors influencing the values of elastic modulus. Today, the composition of concrete combines the classic input components with the significant use of mixed cements, active admixtures and superplasticizers in order to achieve the required compressive strength of concrete and durability while reducing costs. On the other hand, the composition of these concretes has a negative impact on the elastic modulus which are significantly lower than the values derived from compressive strength in Eurocode 2. At the end of the article is a list of measures that are a prerequisite for obtaining the required concrete elastic modulus.

scholarly journals A Cameroonian Study on Mixing Concrete with Wood Ashes: Effects of 0-30% Wood Ashes as a Substitute of Cement on the Strength of Concretes

2021 ◽  
Vol 31 (5) ◽  
pp. 275-282
Author(s):  
Théodore Gautier L.J. Bikoko
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Greenhouse Gases ◽  
Negative Influence ◽  
Wood Ash ◽  
The Other ◽  
Other Hand ◽  
Strength Tests ◽  
Compressive Strength Of Concrete ◽  
Curing Age

To fight against the high cost and the increasing scarcity of cement and at the same time to reduce the CO2 greenhouse gases emission associated with the production of Portland cement, two types of wood ashes as a substitute of cement in the production of concretes were investigated. In this paper, we substituted cement by two types of species of wood ashes namely, avocado and eucalyptus ashes following the proportions ranging from 0% to 30% on one hand, and on the other hand, we added these two types of species of wood ashes namely, avocado and eucalyptus ashes following the proportions ranging from 0% to 10% by weight of cement in the concrete samples. After 7, 14 and 28 days of curing, compressive strength tests were conducted on these concrete samples. The findings revealed that using wood ashes as additives/admixtures or as a substitute of cement in the production/manufacturing of concrete decreased the compressive strength of concrete. Hence, it can be said that wood ash has a negative influence on the strength of concrete. At three percent (3%) and ten percent (10%) of addition, the wood ash from eucalyptus specie offers better resistance compared to the wood ash from avocado specie, whereas at five percent (5%) of addition, the wood ash from avocado specie offers better resistance compared to the wood ash from eucalyptus specie. At thirty percent (30%) of substitution, the wood ash from eucalyptus specie offers better resistance compared to the wood ash from avocado specie. The compressive strengths increase with the increase of curing age.

Influence of Air Content on the Compressive Strength of Concrete

2012 ◽  
Vol 535-537 ◽  
pp. 1790-1793
Author(s):  
Rui Ying Bai ◽  
Ji Wei Cai ◽  
Ji Xu Wu ◽  
Gong Lei Wei
Keyword(s):  
Compressive Strength ◽  
Concrete Strength ◽  
The Other ◽  
Strength Grade ◽  
Air Content ◽  
Other Hand ◽  
Compressive Strength Of Concrete

The influence of air content on compressive strength of C20，C30，C40 and C50 concrete was investigated in this paper. The result shows that this relationship varied with concrete strength grade. For C20~C40 concrete, the air content increases with addition of air entraining agent, while a maximum air content value appears for C50 concrete. The compressive strength of C20 decrease slightly with the air content, on the other hand, that of C40 significantly decreases relatively.

Effect of strain rate, off-axis loading and high-velocity impact damage on the compressive strength of C/SiC composite

2018 ◽  
Vol 53 (4) ◽  
pp. 535-546 ◽  
Author(s):  
M Altaf ◽  
S Singh ◽  
VV Bhanu Prasad ◽  
Manish Patel
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
High Velocity ◽  
Impact Damage ◽  
The Other ◽  
High Velocity Impact ◽  
Fibre Bundles ◽  
Velocity Impact ◽  
Kink Bands ◽  
Other Hand

The compressive strength of C/SiC composite at different strain rates, off-axis orientations and after high-velocity impact was studied. The compressive strength was found to be 137 ± 23, 130 ± 46 and 162 ± 33 MPa at a strain rate of 3.3 × 10−5, 3.3 × 10−3, 3.3 × 10−3 s−1, respectively. On the other hand, the compressive strength was found to be 130 ± 46, 99 ± 23 and 87 ± 9 MPa for 0°/90°, 30°/60° and 45°/45° fibre orientations to loading direction, respectively. After high-velocity impact, the residual compressive strength of C/SiC composite was found to be 58 ± 26, 44 ± 18 and 36 ± 3.5 MPa after impact with 100, 150 and 190 m/s, respectively. The formation of kink bands in fibre bundles was found to be dominant micro-mechanism for compressive failure of C/SiC composite for 0°/90° orientation. On the other hand, delamination and the fibre bundles rotation were found to be the dominant mechanism for off-axis failure of composite.

scholarly journals FOREST IN THE BASHKIRS' VIEW OF THE WORLD

2022 ◽  
pp. 33-40
Author(s):  
Ю. А. Абсалямова
Keyword(s):  
World View ◽  
Construction Materials ◽  
The Other ◽  
Aesthetic Perception ◽  
Food Protection ◽  
Other Hand ◽  
The World ◽  
Other World ◽  
The One ◽  
The Relationship

В статье анализируются особенности восприятия лесного пространства башкирами. На основе языковых, фольклорных материалов сделана попытка раскрыть различные аспекты взаимоотношений лес - человек, образ леса в картине мира башкир. Как и в большинстве традиционных культур, в целом мифологический образ леса носит отрицательный характер. В фольклоре он часто описывается как тёмный, мрачный, неизвестный, таящий опасности, противопоставляясь обжитому и освоенному пространству селений. Лесной пандемониум также представлен в основном отрицательными персонажами. В целом образ леса в традиционной картине мира башкир предстаёт довольно неоднозначным. С одной стороны - это категория, связанная с потусторонним миром, неизведанная, «чужая» территория. С другой - лес издавна являлся источником различных благ - в виде строительного материала, пушнины, различных продуктов питания, укрывал от врагов. The article analyzes the features of Bashkirs' perception of the forest space. On the basis of the materials of the epos, folklore, folk ideas, an attempt was made to reveal the various aspects of the relationship between forest and man, the image of the forest in Bashkirs' world view. As in most traditional cultures, the mythological image of the forest as a whole is negative. In folklore, it is often described as dark, gloomy, unknown, fraught with danger, being contrasted with the inhabited and developed space of the villages. The forest pandemonium is also represented mainly by negative characters. On the other hand, in the domestic perception forest is valued for the benefits derived from it: shelter, food, protection from enemies. In addition, Bashkirs, distinguished by a developed aesthetic perception and contemplative thinking, appreciated its beauty, which is also reflected in folklore. In general, the image of forest in the Bashkirs' traditional view of the world appears rather ambiguous. On the one hand, it is the category associated with the other world, unknown, «foreign» territory. On the other hand, the forest has long been a source of various benefits - in the form of construction materials, furs, various food products, and it sheltered them from enemies.

scholarly journals Social Utopias and Engineering Design

2020 ◽  
Vol 3 (1) ◽  
pp. 570-583
Author(s):  
Waldemar Czajkowski
Keyword(s):  
Engineering Design ◽  
Practical Importance ◽  
The Other ◽  
Effective Solution ◽  
Possible World ◽  
Adequate Knowledge ◽  
Other Hand ◽  
Engineering Sciences ◽  
Global Problems ◽  
The One

AbstractA paradox of our time is identified: on the one hand – the development of one global system (ecological, technological and social), on the other hand – the still increasing “balkanization” of science. The dynamics of this systems is a source of well-known numerous global problems. Its possibly effective solution needs adequate knowledge about the system. For this reason, counteraction to “balkanization” of science is of great practical importance. And this counteraction should comprise not only development of “transboundary” sciences (such as biochemistry or social psychology) but also establishing and developing links between very distant disciplines. This text is intended as a contribution to linking social and engineering sciences. The notion of design plays the central role in this text. Its meaning in the engineering sciences. The notion of utopia has been chosen as a partial counterpart to the term of engineering design. This notion was defined using a concept of possible world – taken from modal logic. It encompasses two ideas: this of design and that of prediction, It is claimed that we need many utopias and that their plurality is of fundamental importance for protecting us against the threats of utopianism. The paper suggests that social utopias can play a heuristic role in engineering design (particularly in the initial phase of defining technological problems), and – on the other hand – that the theory of engineering design can be supportive for, badly needed, development of methodology of utopias creation.

scholarly journals Assessment of Workability and Compressive Strength of Rice Husk Ash-Blended Palm Kernel Shell Concrete

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
K. O. Oriola
Keyword(s):  
Compressive Strength ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Construction Materials ◽  
Palm Kernel ◽  
Lightweight Aggregate ◽  
Strength Properties ◽  
Lightweight Aggregate Concrete ◽  
Palm Kernel Shell ◽  
Compressive Strength Of Concrete

The evaluation of agro-industrial by-products as alternative construction materials is becoming more significant as the demand for environmentally friendly construction materials increases. In this study, the workability and compressive strength of concrete produced by combining Palm Kernel Shell (PKS) and Rice Husk Ash (RHA) was investigated. Concrete mixes using a fixed content of 15% RHA as replacement for cement and 20, 40, 60, 80 and 100% PKS as replacement for crushed granite by volume with the mix ratios of 1:1½:3, 1:2:4 and 1:3:6 were produced. The water-to-cement ratios of 0.5, 0.6 and 0.7 were used for the respective mix ratios. Concrete without PKS and RHA served as control mix. The fresh concrete workability was evaluated through slump test. The concrete hardened properties determined were the density and compressive strength. The results indicated that the workability and density of PKSC were lower than control concrete, and they decreased as the PKS content in each mix ratio was increased. The compressive strength of concrete at 90 days decreased from 27.8-13.1 N/mm2, 23.8-8.9 N/mm2and 20.6-7.6 for 1:1½:3, 1:2:4 and 1:3:6, respectively as the substitution level of PKS increased from 0-100%. However, the compressive strength of concrete increased with curing age and the gain in strength of concrete containing RHA and PKSC were higher than the control at the later age. The concrete containing 15% RHA with up to 40% PKS for 1:1½:3 and 20% PKS for 1:2:4 mix ratios satisfied the minimum strength requirements for structural lightweight aggregate concrete (SLWAC) stipulated by the relevant standards. It can be concluded that the addition of 15% RHA is effective in improving the strength properties of PKSC for eco-friendly SLWAC production..

The Effect of Different Curing Conditions on Compressive Strength of Concrete

2017 ◽  
Vol 60 (3) ◽  
pp. 147-153
Author(s):  
Muhammad Arslan ◽  
Muhammad Asif Saleem ◽  
Maria Yaqub ◽  
Muhammad Saleem Khan
Keyword(s):  
Compressive Strength ◽  
Research Work ◽  
Concrete Structures ◽  
Strength Test ◽  
The Other ◽  
Cylindrical Shape ◽  
Curing Conditions ◽  
Compressive Strength Test ◽  
Different Types ◽  
Compressive Strength Of Concrete

The focus of this research work was to analyse the effect of different types of curing oncompressive strength of concrete structures. For this purpose, 54 test specimens of cylindrical shape wereprepared. These specimens were cured with different methods and were tested on different age days toanalyse the effect of curing on compressive strength. Test specimens cured with conventional water curingmethod gives the highest results as compared to the other adopted methods.

scholarly journals Effectiveness of Calcium Carbonate Whisker in Cementitious Composites

2020 ◽  
Author(s):  
Mingli Cao ◽  
Mehran Khan ◽  
Shakeel Ahmed
Keyword(s):  
Calcium Carbonate ◽  
Large Scale ◽  
Low Cost ◽  
Complex Structure ◽  
Construction Materials ◽  
Physical And Mechanical Properties ◽  
Cementitious Composites ◽  
Toughening Mechanism ◽  
Micro Scale ◽  
Calcium Carbonate Whisker

Cementitious composites are porous material having complex structure system consist of hydration products, un-hydrated cement particles and pore solutions of various scales. Calcium carbonate whisker is a new type of low cost micro-scale filler fiber gaining popularity in the field of construction materials. However, addition of whisker has effect on physical, mechanical and microstructural characteristics of cementitious composites. Also, the low production cost of whisker will make the use of micro fiber more extensive in large scale construction projects. In this study, the effect of calcium carbonate whisker on physical, mechanical and microstructural properties of cementitious composites with different fiber contents are investigated. The fluidity, drying shrinkage, pore structure, impact resistance, compressive, flexural and splitting-tensile strength of whisker-mortar are considered. The scanning electron microscopy analysis is also performed to examine the microstructural and toughening mechanism of whisker reinforced composites. It was concluded that the addition of calcium carbonate whisker up to 10 % improves the physical and mechanical properties of cementitious composites and is suggested to be the optimize content. The calcium carbonate whisker also resists the crack propagation at micro scale and showed the toughening mechanism with better interfacial properties between whisker and matrix.

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