scholarly journals AVALIAÇÃO DE DESEMPENHO DE PAVERS INTERTRAVADO PRODUZIDOS COM REJEITOS GERADOS NOS DESDOBRAMENTOS DE ROCHAS ORNAMENTAIS

2020 ◽  
Vol 15 (2) ◽  
pp. 245-261
Author(s):  
Thais Cristina Bastos De Araujo ◽  
Harerton Dourado

RESUMO: O presente trabalho teve por finalidade estudar a resistência à compressão dos pavers produzidos com rejeitos gerados no desdobramentos de rochas ornamentais. Foram elaborados diversos traços com diferentes porcentagens sendo substituído parte do pó de pedra por lama abrasiva. Os estudos mostraram que a adição da lama abrasiva na confecção dos blocos apresentou um resultado satisfatório, aumentando a resistência à compressão, os traços Padrão, 1 e enquadraram-se nas Normas Australiana e Africana, já o Traço 3 e o Traço 4 alcançaram além das Normas Australiana e Africana também a Norma Brasileira, que exige no mínimo 35MPa para tráfego de pedestres, veículos leves e veículos comerciais de linha. ABSTRACT: The aim of this paper was to study the compressive strength of pavers produced with tailings generated in the development of ornamental rocks. Several strokes with different percentages were elaborated and part of the stone dust was replaced by abrasive mud. Studies have shown that the addition of abrasive sludge in the making of the blocks has shown a satisfactory result, increasing the compressive strength, the Standard strokes, 1 and fit the Australian and African Standards, while the Trace 3 and Trace 4 reached beyond Australian and African Standards also the Brazilian Standard, which requires at least 35MPa for pedestrian, light vehicle and commercial line traffic.

Author(s):  
Divesh Sharma

In this review article, the usage of bitumen, sisal fiber and the sisal fiber for improving the strength parameters of concrete is discussed in detail. Numerous research studies related to the usage of bitumen, sisal fiber and stone dust are studied in detail to determine the results and outcome out of it. Previous research works showed that all, these materials were enhancing the strength and durability aspects of the concrete and depending upon the research studies certain outcomes has been drawn which are as follows. The studies related to the usage of the bitumen or asphalt in concrete so as to produce bituminous concrete or asphaltic concrete, the previous research works conclude that the maximum strength was attained at 5 percent usage of the bitumen and after further usage the general compressive strength of the concrete starts declining. The previous studies related to the usage of the sisal fiber showed that with the usage of the sisal fiber in the concrete, the strength aspects of concrete were improving and the maximum strength was obtained at 1.5 percent usage of the sisal fiber and after his the strength starts declining. Further the studies related to the usage of the stone dust showed that with the usage of stone dust as partial replacement of the natural fine aggregate the compressive strength of the concrete was improving and it was conclude that with the increase in the percentage of the stone dust, the compressive strength of the concrete was increasing.


Wood Research ◽  
2021 ◽  
Vol 66 (4) ◽  
pp. 582-594
Author(s):  
FRANCISCO ANTONIO ROCCO LAHR ◽  
VINICIUS BORGES DE MOURA AQUINO ◽  
FELIPE NASCIMENTO ARROYO ◽  
HERISSON FERREIRA DOS SANTOS ◽  
SERGIO AUGUSTO MELLO SILVA ◽  
...  

The Brazilian standard ABNT 7190 (1997) establishes the strength classes C20, C30, C40 and C60 for the proper framework of the different wood types in the group of hardwoods. Associated with the strength class, which is based on the compressive strength characteristic value parallel to the fibers (fc0,k), the standard stipulates the respective values representing the stiffness (Ec0), with 19500 MPa being the reference value for the class C40, essential variables in structural design. For being the C40 class is the one with the greatest amplitude (20 MPa), it is possible that the value 19500 MPa is not the best representation of stiffness. This work aimed to verify the representativeness the stiffness value established by the Brazilian standard for C40 wood. The result obtained from the average confidence interval indicates the value of 14110 MPa as being the most representative, which may imply structures that are supposedly more rigid than they really are.


Today’s world is always leads to development in technology as well as the economic growth though sometime these will affect the environment badly. That’s why world environmental commission coined the termed called sustainable development where development takes place without hampering the others’ needs. Concrete industry is rapidly growing industry in India which consumes lots of natural resources during the production of concrete. Here Stone dust is used as a sustainable material in place of sand partially. M25 grade of concrete has been chosen for the experiments. Different mechanical properties of concrete like compressive strength, Split tensile, flexural strength etc. and Microstructural features like SEM, EDX have been included in this study. Compressive Strength and flexural strength test results shown the increase in the strength. Sulphate Resistance Properties have been tested by curing the cubes in the MgSO4 solution and increase in weight has been observed. Similarities are found in the SEM pictures


2001 ◽  
Vol 44 (10) ◽  
pp. 273-277 ◽  
Author(s):  
C. Huang ◽  
J.R. Pan ◽  
K.-D. Sun ◽  
C.-T. Liaw

In this study, an attempt was made to use water treatment plant (WTP) sludge and dam sediment as raw materials for brick-making through the sintering process. The sinter of dam sediment fired at 1,050°C had a less than 15% ratio water absorption, and its compressive strength and bulk density met the Chinese National Standard (CNS) for first level brick. The WTP sludge sinter made under the same operating condition exhibited higher water absorption, larger shrinkage, but poorer compressive strength. When fired at 1,100°C, the shrinkage of the WTP sludge sinter was as high as 45%, although its compressive strength and water absorption of WTP sludge brick still met the standard for the first level brick. To reuse WTP sludge in an economical way, mixtures of various proportions of WTP sludge to dam sediment are used as raw materials. A satisfactory result was achieved when the ratio of the WTP sludge was less than 20% of the mixture. Results of tests indicated that the sinter of dam sediments which are fired at a temperature of 1000~1100°C has reached the requirement for tile brick.


2012 ◽  
Vol 5 (6) ◽  
pp. 798-811
Author(s):  
A. B. Rohden ◽  
D. C. C. Dal Molin ◽  
G. L. Vieira

The Brazilian standard NBR 7212 states that the time of transporting the concrete between the start of mixing should be less than 90 minutes so that by the end of the discharge is a maximum of 150 minutes. Yet often, in construction, concrete is used after this period. In order to investigate the behavior of concrete after setting time of cement was cast six concrete mixtures with two types of cement. The mixtures were produced and kept fresh for six hours, adopting a procedure for maintenance of abatement by superplasticizer and agitation. The results show that of the test piece molded over six hours of maintained or increased the compressive strength average.


2013 ◽  
Vol 684 ◽  
pp. 172-176
Author(s):  
Alireza Ghaffari ◽  
Amirreza Ghaffari

To enhance the mechanical and compressive strength of lime mortar(lime-sand ) the fly ash was added to the compound to improved the engineering performance of lime mixture .The addition of fly ash and lime stone dust to clay soils reduce their plasticity characteristics, swell potential and improve their compressive strength (Brooks et al. 2011) .Boardman et al (2001) observed that no significant pozzolonic activity appears to take place until 7 days of curing during their experiments at room temperature .In this research the effect of fly ash at different range from 30 to 70 percent of mix by varying lime percentage from 6 to 20 percent with thermodynamic parameters of their reaction was assessed in normal and raised temperature by curing compacted specimens in the laboratory .The compressive strength of fly ash and lime mixture are determined on curing period up to 28 days in normal state and one days on raised one .The Result portrayed that raised temperature highly boosted the compressive strength of the mix from 30 to 120 percent at different range of fly ash mixture with lime.


2012 ◽  
Vol 5 (6) ◽  
pp. 757-780 ◽  
Author(s):  
E. Pereira ◽  
M. H. F. de Medeiros

To estimate the compressive strength of concrete is necessary in many reinforced concrete structures inspection works. In Brazil, the standard tests for this purpose are: Compressive test in drilled cores, rebound hammer test and ultrasonic test. In the United States and Europe are also regulated other techniques. The aim of this paper is to analyze the use of Pull Off test as an inspection tool of concrete and also disclose the possibility of use of complementary techniques to the standard ones in Brazil. The results show that the Pull Off test results in high correlation (R²> 0.93) with the compressive strength, measured in cylindrical and prismatic specimens. The rebound hammer test did not show satisfactory correlation (R²≅0.6) for the case of cylindrical specimens. The ultrasonic test showed high correlation (R²> 0.98), but behaves differently with the shape changing of the specimens.


Author(s):  
S.O Ajamu ◽  
I.A Raheem ◽  
S.B Attah ◽  
J.O Onicha

Natural river sand is one of the important constituent materials in concrete production while stone dust is a material obtained from crusher plants which is also sometimes being used either partially or fully in replacement of natural river sand in concrete production. Use of stone dust in concrete not only improves the quality of concrete but also conserve the natural river sand. However, due its scarcity and environmental degradation caused resulting from excessive mining of Natural river sand, there is need to investigate an alternative material of the same quality which can replace river sand in concrete production. In the present study, experiments were carried out to study the gradation of aggregates, workability, compressive strength and split tensile strength of concrete made using quarry dust as replacement of fine aggregate at 0, 25, 50, 75, and 100%. Grade M15 of concrete was produced with ordinary Portland cement (OPC) for referral concrete while M25 of concrete was prepared for compressive strength and split tensile strength concrete. Workability and Compressive strength were determined at different replacement level of fine aggregate and optimum replacement level was determined based on compressive strength. Results showed that by replacing 50% of fine aggregate with quarry dust, concrete of maximum compressive strength can be produced as compared to all other replacement levels. The effect of quarry dust on compressive strength and split tensile strength was investigated and from the overall result obtained, it was observed that the compressive strength and split tensile strength increased significantly for all the curing ages from 0% to 50% replacement level of quarry dust. Maximum value obtained for 28day compressive and tensile strength were 25N/mm2 and 2.3N/mm2 respectively and this occurred at 50% replacement.


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