No abstract

No abstract

No abstract

No abstract

No abstract

Abstract.Pozzolanicity is a very interesting issue regarding building materials, as a way to enhance mortars and concrete durability. This property results from the reaction between calcium hydroxide and silica and alumina based materials. Different types of natural and artificial pozzolans show pozzolanic activities that differ depending on the materials characteristics. Therefore, the study of this property, namely its reactivity with calcium hydroxide, reveals itself to be important in the selection of the type and content of these materials. This paper presents the results of several pozzolanic reactivity methods, applied to different pozzolanic materials. The selected pozzolanic methods include Chapelle method, Fratinni method and Strength Activity Index. Those tests have been applied to evaluate the reactivity of various kinds of artificial pozzolans. The correlation between the test methods are presented and discussed.

No abstract

This research analyses the shrinkage and creep performance of concrete with recycled aggregates from various Portuguese construction and demolition waste recycling plants, studying the influence of the properties and composition of each recycled aggregate source on the characteristics of concrete produced with them. Recycled aggregates from four plants were used in the concrete mixes produced in this research, of which two were coarse recycled aggregates and two were fine recycled aggregates. During this experimental campaign, the behaviour of the mixes with recycled aggregates was evaluated by three fresh-state concrete tests (slump using the Abrams cone, density, and air content) and two hardened-state concrete tests (shrinkage and creep). It was found that the incorporation of recycled aggregates caused a qualitative drop in the concrete's properties. The properties of the concrete mixes were significantly dependent on the source (and composition) of the recycled aggregates.