nano materials have been widely used in laboratory and industrial scales in order to improve various properties of concrete and concrete mixture. the mainstream practice of the researches in this field is to add metallic nano-particles into the concrete mixture. the present research focuses on adding micro-nano air bubbles (mnab) into water before mixing it with aggregate and cement mixtures. i...

This paper aims at investigating the influence of partial replacement of Portland cement with ultrafine fillers compared to limestone powder on the durability and mechanical characteristics of concrete. For this purpose, ultrafine calcium carbonate materials with different specific surface areas of 9.7 and 15.1 m2/g and limestone powder (0.72 m2/g) were used. The results indicate that the ultra...

There is a worldwide interest in using fibers of different types in concrete mixtures. In this regard, as the use of PET fibers has gradually increased during the last decade, this study aims to investigate the effects of PET fibers on the mechanical properties of hardened concrete and the workability of fresh concrete. To this end, different contents of PET fibers (PC= %0, %0.5, %1 and %1.5) a...

Corrosion of steel is one of the most important potential dangers and threats in concrete structures. Corrosion of steel embedded in reinforced concrete plays a key role in reducing the strength and durability of reinforced concrete. Several studies have proposed that alternative approaches to enhancing the performance of reinforced concrete and its resistance to corrosion. In this study, the r...

an application of aerated concret (foam concrete) was experimentally studied. in this study the compressive strength of the proposed concrete was measured the effect of parameters such as aggregate size of broken stone, quantity of cement and various densities were exprementally studies, and the best mixture was select.these prepared mixtures are practically useful to optimize the consumption o...

In this research, the performance of ultrasonic pulse velocity (UPV) in concrete is examined as a nondestructive experiment in order to estimate mechanical (compressive and tensile strength) and durability (water absorption) properties of fiber-reinforced self-compacted concrete For this purpose 11 mixture designs containing 3 types of fibers (steel: 0.1, 0.2, 0.3 and 0.4 percent by volume, Pol...

Recycling waste tire rubber by incorporating it into concrete has become the preferred solution to dispose of waste tires. In this study, the effect of the volume content of crumb rubber and pretreatment methods on the performances of concrete was evaluated. Firstly, the fine aggregate and mixture were partly replaced by crumb rubber to produce crumb rubber concrete. Secondly, the mechanical an...

this paper describes the effects of reinforcement by randomly distributed nylon fibers and addition of nanoclay on some engineering properties of a typical asphalt concrete. the properties of asphalt concrete reinforced by different percentages of 25 mm nylon fibers have been compared with those of the mixtures containing different percentages of nanoclay and those in which both the fibers and ...

the performance of asphaltic pavements during their service life is highly dependent on the mechanical properties of the asphaltic layers. therefore, in order to extend their service life, scientists and engineers are constantly trying to improve the mechanical properties of the asphaltic mixtures. one common method of improving the performance of asphaltic mixtures is using different types of ...