Oxygen diffusion would not be important for healthy concrete. Once concrete is carbonated, however, oxygen diffusion is very crucial to lead reinforcement corrosion. Therefore, oxygen is always a potential threat of reinforcement corrosion in concrete and oxygen diffusivity is a material parameter for service life determination and durability designing of the concrete. One of the simple approac...

Nanomechanical Properties of Cementitious Materials Paramita Mondal Although cementitious construction materials are mainly used in a large scale and in huge quantities, fundamental properties such as strength, ductility, creep, shrinkage, and fracture behavior depend, to a great extent, on structural elements and phenomena which are effective at the microand nanoscale. This research involves c...

Copper-mine tailings are the residual products after the extraction of precious copper metal from copper ores, and their storage can create numerous environmental problems. Many researchers have used copper-mine tailings for the preparation of geopolymers. This paper studies the enhancement of the cementitious activity of copper-mine tailings in geopolymer systems. First, copper-mine tailings a...

This study was carried out to evaluate the effects of blended ash mixture on mechanical properties of concrete. In this study two reference mixtures were used. One of the mixtures was a no-fly ash mixture, and the other mixture contained 35% unblended Class C fly ash. Additional mixtures were composed of three blends of Class C and Class F fly ash while maintaining a total fly ash content of 40...

This paper addresses the property requirements of repair materials for high durability performance for concrete structure repair. It is proposed that the high tensile strain capacity of High Performance Fiber Reinforced Cementitious Composites (HPFRCC) makes such materials particularly suitable for repair applications, provided that the fresh properties are also adaptable to those required in p...

If we are to monitor the chemical processes in cementitious materials, then pH assays in the pore solutions of cement pastes, mortars, and concretes are of key importance. However, there is no standard method that regulates the sample-preparation method for pH determination. The state-of-the-art of different methods for pH determination in cementitious materials is presented in this paper and t...

This paper presents work toward the studying of a new family of self-healing cementitious material. This innovative system features the design of microcapsules with calcium sulfoaluminate cement (CSA) as healing agent. The aim of this study is to comprehensively monitor the whole crack-healing process of microcapsules based self-healing system by means of X-ray computed tomography (X-ray CT). I...

in spite of the fact that cementitious and concrete materials are mainly used on a large scale and inhuge quantities for roads, dams, bridges and building constructions, the mechanical behavior of thesematerials depends to a great extend on structural elements and phenomena which are effective on amicro and nanoscale. although this is well known by researchers, material producers and engineersf...

In this paper, we present a new method to reconstruct large volumes of nontransparent porous materials at submicron resolution. The proposed method combines fluorescence laser scanning confocal microscopy with serial sectioning to produce a series of overlapping confocal z-stacks, which are then aligned and stitched based on phase correlation. The method can be extended in the XY plane to furth...

The non-steady-state migration test for measuring the chloride migration coefficient was performed on mortar specimens fabricated with supplementary cementitious materials. A careful examination of the test results revealed that the use of more than one specimen with different test durations is recommended for obtaining reliable chloride migration coefficients. Additionally, the voltage applied...