scholarly journals Relations between indirect tensile and flexural strengths for dry and plastic concretes

2013 ◽  
Vol 6 (6) ◽  
pp. 854-874 ◽  
Author(s):  
J. T. Balbo

Indirect tensile strength is not usually used for concrete mixtures proportioning and its technological control; flexural strength tests under third point loads arrangement are the pattern for such goals. Indeed, neither of such tests have the capability to set up the actual strength of a concrete slab since its response is under plane stress state. A critical review of the basic concepts on both kinds of tests allows foreseeing its limitations as well as how to overcome such shortcomings. At last correlations between the two kinds of tensile strength are presented considering dry and plastic concretes typically applied on paving, corroborating to former results achieved for plastic concretes.

2021 ◽  
Vol 3 (1) ◽  
pp. 1-5
Author(s):  
Saad Issa Sarsam

Prediction of the strength properties of roller compacted concrete from mathematical models is significant for rapid decision of the quality of the pavement. In the present assessment, roller compacted concrete slab samples have been prepared in the laboratory using 12 percentage of Portland cement by weight of aggregates. Cube, core, and beam specimens were extracted from the slab samples and tested for compressive, indirect tensile, and flexural strength at the age of 28 days. Strength test results were corelated among each other and mathematical models were obtained. It was observed that low significance of aggregates gradation type on the compressive and tensile strength exists. However, high influence of dense gradation on flexural strength could be detected. The flexural strength of dense graded mixture is higher than that of gap graded mixtures. The compressive strength of gap graded mixture is higher than that of dense graded mixture. It can be concluded that the flexural strength is higher than the tensile strength by (2.17 and 1.24) folds for dense and gap graded mixtures respectively. The compressive strength is higher than tensile strength by (5.72 and 4.87) folds for dense and gap graded mixtures respectively. The compressive strength is higher than the flexural strength by (3.4 and 2.49) folds for dense and gap graded roller compacted concrete respectively. The obtained mathematical models exhibit high coefficient of determination and may be implemented in verification of the specific strength property based on other measured strength properties of roller compacted concrete.


2021 ◽  
Author(s):  
Piotr Zieliński

The effect of using reclaimed asphalt pavements (RAP) to asphalt concrete mixtures besides their utilization is to reduce the amount of the new bituminous binder and aggregate added to hot mix asphalt. This publication presents studies on asphalt mixtures with an increased up to 40% amount of RAP additive with the simultaneous use of 2 types of added bitumen, i.e. 35/50 and PMB 25/55-60. The aim of the paper is the evaluation of the basic mixture properties in a wide range of operating temperatures, as a part of the AC testing at high temperatures, the resistance to rutting at 60° C and indirect tensile strength at 40° C. The assessment of properties at intermediate operating temperatures is based on indirect tensile tests, including: elastic stiffness modulus at 5° C, 15° C and 30° C and static strength at 25° C. The low temperature properties have been tested in water and frost resistance tests by indirect tensile strength ratio. The results of the study were subjected to the analysis of the statistical significance of differences, which showed an improvement in the resistance of AC with the addition of RAP to the formation of permanent deformations and an increase in the stiffness modulus as well as indirect tensile strength. There was no adverse effect of the RAP additive on asphalt mixtures resistance to water and frost action.


2020 ◽  
Vol 12 (10) ◽  
pp. 4243 ◽  
Author(s):  
Eduardo-Javier Elizondo-Martinez ◽  
Piergiorgio Tataranni ◽  
Jorge Rodriguez-Hernandez ◽  
Daniel Castro-Fresno

Alternative materials to replace cement in pavements have recently been widely studied with the purpose of decreasing the environmental impacts that the construction industry generates. In this context, the implementation of sustainable urban drainage systems has grown, especially with porous pavements, with the intention to reduce water and environmental impacts. In the present investigation, the addition of alternative materials to minimize the use of cement in porous concrete pavements is evaluated. Starting from a partial substitution of Portland cement with metakaolin, experimental geopolymer concretes were produced with metakaolin and waste basalt powder according to several dosages. Two sets of mixtures were analyzed to evaluate the Porous Concrete Design (PCD) methodology for porous concrete mixtures with alternative materials. A deep analysis was proposed for the evaluation of the mechanical and volumetric properties of the mixtures. Results demonstrated that replacing 5% of cement with metakaolin can increase both permeability and indirect tensile strength. Geopolymer mixtures can achieve permeability significantly higher than the traditional porous concrete, but this decreases their indirect tensile strength. However, considering the promising results, an adjustment in the mix design of the geopolymer mixtures could increase their mechanical properties without negatively affecting the porosity, making these materials a suitable alternative to traditional porous cement concrete, and a solution to be used in urban pavements.


2021 ◽  
Vol 10 (1) ◽  
pp. 1-10
Author(s):  
Chavan Ravishankar ◽  
M.S. Nagakumar ◽  
H.K. Krishnegowda ◽  
Abhilash R Prasad

Study work on the effectiveness and use of Industrial by-products (IBP) in flexible pavements is restricted. Several factors however need to be analyzed specifically before a greater proportion of industrial by-products can be used in bituminous concrete mixtures with a high level of confidence. Effects of copper slag on volumetric and strength parameters such as Marshall Parameters, static tensile properties, and moisture resistivity of bituminous concrete mixtures using copper slag as mineral fillers need to be examined and thoroughly analyzed. Quantitative analyses of the elements and the morphology of the copper slag have been studied by Energy Dispersive X-ray Analyzer (EDX) and Scanning Electron Microscope (SEM). The use of copper slag as a mineral filler in bituminous concrete grade-2 mixtures showed an increase in stability, indirect tensile strength, and moisture resistance compared to traditional mixtures. Keywords— Industrial by-products (IBP), Indirect Tensile Strength, Moisture resistivity, SEM, EDX


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