Strength optimization of reactive powder concrete

Otimização da resistência mecânica de concretos de pós reativos

abstract:

Recent reports on reactive powder concrete address important aspects regarding its performance. Several techniques are used to improve the design of such concretes. Ultra-high compressive strengths have been reported with the application of pre-setting pressure and autoclave curing. The objective of this work is to evaluate the use of very fine quartz powder to replace fine aggregate, nanosilica, and inorganic pigments to optimize mechanical properties of reactive powder concrete. The experimental work was developed in three distinct phases. In the first phase, mix-proportions of reactive powder concrete have been developed, considering different maximum aggregate sizes (1.2, 0.6, 0.075, and 0.045 mm). In the second phase, the influence of nanosilica on the properties of reactive powder concrete was evaluated. In the third phase, the effect of the addition of yellow, green, orange, and blue inorganic pigments to the reactive powder concrete mix-design was evaluated. Results show that the maximum aggregate size influences the compressive strength of the reactive powder concrete. A decrease from 1.2 mm to 0.045 mm in the maximum aggregate size resulted in 156 MPa increase in the compressive strength. The type of pigment did not significantly influence the compressive strength of the reactive powder concrete. The mix-proportion that resulted in the highest compressive strength (310.7 MPa) was designed using yellow pigment.

Keywords:
powder-reactive concrete; quartz powder; inorganic pigments; nanosilica