Ali Mardani-Aghabaglou

EFFECT OF CEMENT FINENESS ON PROPERTIES OF CEMENTITIOUS MATERIALS CONTAINING HIGH RANGE WATER REDUCING ADMIXTURE

ABSTRACT The effect of cement fineness on the fresh state and rheological properties as well as compressive strength of cementitious systems was investigated. A CEM I 42.5R portland cement containi...

Water Transport of Lightweight Concrete with Different Aggregate Saturation Levels

This study evaluates the effect of saturation degree of two different lightweight aggregate types with different water absorption characteristics compared to a limestone aggregate in a constant water-cement ratio (w/c) concrete mixture. Water transport properties such as water absorption, water sorptivity, aggregate-based drying shrinkage, and freezing-and-thawing resistance of the mixtures were investigated. Finally, SEM analysis was performed to evaluate the interfacial transition zone characteristics of these concrete mixtures in light of said findings. The test results indicated that the transport properties and freezing-and-thawing resistance of the concrete mixtures were improved at early ages and the total concrete drying-shrinkage was decreased by increasing saturation level of aggregate. However, aggregate moisture content does not have a significant effect on the compressive strength of the concrete mixtures.

Transport properties and freeze-thaw resistance of mortar mixtures containing recycled concrete and glass aggregates

The effects of recycled glass (RG) and recycled concrete (RC) fine aggregates on the compressive strength, ultrasonic pulse velocity, dynamic elastic modulus, transport properties and freeze–thaw resistance of mortar mixture were investigated comparatively. Nine different mortar mixtures were prepared by partial replacement of crushed-limestone fine aggregate with recycled aggregates. Compared to that of the control mixture, the transport properties of RC aggregate-bearing mixtures inversely affected with increasing the replacement level of this aggregate. The opposite results were obtained in RG aggregate-containing mixtures. Frost resistance of mortar mixture improved by using both of the recycled aggregates. Improvement of frost resistance of RC mixtures was attributed to the presence of improved Interfacial transition zone between matrix and coarse aggregate (ITZ) in RC-bearing mixture and to the high number of pores existing in the well-distributed RC aggregates in the mixture. Perhaps, these pores provide additional sites for the water escaped from capillary pores upon ice formation.

DURABILITY PERFORMANCE AND DIMENSIONAL STABILITY OF POLYPROPYLENE FIBER REINFORCED CONCRETE

Abstract In this study, the durability performance and dimensional stability of polypropylene fiber reinforced concrete mixture were investigated. For this purpose, two series of concrete mixtures, including a 0.45 water/cement ratio was prepared both in the absence and presence of fiber. A CEMI 42.5 R type portland cement and crushed limestone aggregate with a maximum particle size of 25 mm were used. In addition to the control mixture without fiber, three different concrete mixtures were prepared by adding polypropylene fiber as 0.4%, 0.8% and 1% of total volume into the mixture. The time-dependent fresh state properties, strength, ultrasonic pulse velocity, transport properties, drying shrinkage and freeze-thaw resistance of concrete mixtures, sodium sulfate attack and abrasion were investigated comparatively. Test results demonstrated that utilization of fiber affected the fresh properties of the concrete mixtures negatively. However, the 0.8% fiber-bearing mixture showed the highest performance in te...

Effect of Cement C3A Content on Properties of Cementitious Systems Containing High-Range Water-Reducing Admixture

AbstractThe effect of cement tricalcium aluminate (C3A) content on the properties of cement paste, mortar, and concrete mixtures containing high-range water-reducing (HRWR) admixture was investigat...