h i g h l i g h t sIt is feasible to incorporate crushed concrete powder in order to achieve maximum use of the recycled concrete. The influence of admixtures must be studied not only in fresh mixtures but also in hardened concrete. Petrographic studies revealed that the incorporation of crushed concrete powder makes the mortar matrix denser. a b s t r a c tRecycled aggregates are made from crushed waste concretes and can be used as a replacement of natural aggregates in concrete production. Despite having lower density and higher absorption than natural aggregates, they can be used to manufacture conventional concretes with good performance if they are added in the proper amounts. To make self-consolidating concretes, the same aggregates used to manufacture conventional concretes can be used, but in order to increase segregation resistance and keep mix cohesion, a large amount of fine aggregates and a suitable admixture are required. The main goal of this work is to study the influence of recycled aggregates on self-consolidating concrete. Concretes were mixed with 50% of the coarse aggregate replaced by recycled aggregates (Patagonia gravel) and with 20% of the fine aggregate (natural sand) replaced by crushed concrete powders. Fresh concrete properties were tested, and physical and mechanical properties were determined in the hardened state. The petrographic composition of the concrete was examined to assess the interfacial transition zone and the contribution of the powders to the mortar microtexture. The results vary depending on the type of admixture and aggregate. However, it is shown that the inclusion of these crushed aggregates to make good selfconsolidating concrete is feasible.
Over their lifetime, concrete structures can suffer from different pathologies, one of them is exposure to high temperatures, which diminishes their load‐bearing capacity. This study describes how different concrete types were exposed to high temperatures. To simulate fire extinction, where the temperature of the overheated concrete descends suddenly, different cooling systems were applied: slowly cooling in the open air and fast cooling by spraying different water volumes. Several physical–mechanical characteristics were analyzed such as compressive strength, splitting tensile strength, porosity, capillary suction, and carbonation depth. Ultrasound nondestructive tests were conducted to quantify deterioration. A petrographic study using a stereomicroscope and microscopy of polarization was performed on thin sections to evaluate aggregate composition and concrete characteristics, focusing on interface areas. Physical and mechanical properties were affected by the increase in temperature, with damage worsening through the appearance of cracks and microcracks when water is used as a cooling system.
Concrete structures can suffer different pathologies, one of which may be due to exposure to high temperatures. In this briefing paper, different concrete types were exposed to high temperatures. To simulate fire extinction, where the temperature of the overheated concrete descends suddenly, different cooling systems were applied: slowly cooling in the open air and fast cooling by spraying different water volumes. Physical and mechanical properties were affected by the increase of the temperature, making the damage worse, when water was used as the cooling system. Sclerometer and ultrasound non-destructive tests were conducted to quantify deterioration and a relationship with the compressive strength results was established.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.