Amaia Santamaría

Early Concrete Structures: Patented Systems and Construction Features

ABSTRACT Reinforced concrete structures came to Spain in the late-19th century, somewhat after the development of this new construction material elsewhere in Europe. Their introduction was pioneered in industrialized areas, especially Northern Spain, under systems first patented in other European countries. Local constructors built structures under patents with little or no explanations to account for calculation, design, and construction technique. Some of these buildings from the recent past are now listed buildings. This study centres on three construction projects under patented systems: Our Lady of “La Antigua”, Orduña (Monier system), “La Ceres” flour mill, Bilbao (Hennebique system), and Alhóndiga, Bilbao (Blanc system). Preliminary structural studies analyzed morphology, reinforcements, concrete strength and pathological processes in each structure. Their results are compared with information taken from the patent systems in use at the time. This useful information on the structures, which may be expanded in future research, clearly describes the relationship between patent specifications and reality.

Fiber Reinforced Concrete Manufactured with Electric Arc Furnace Slag

The use of electric arc furnace slag (EAFS), a by-product of the steelmaking industry, as an aggregate in concrete has been demonstrated to be a good practice in its manufacture. Furthermore, the incorporation of fibers in concrete provides a more ductile behavior, increasing their tenacity and load capacity, improving the flexotraction strength and controlling shrinkage cracking. The purpose of this research was to study the performance improvement by reinforcing steel-slag concrete with metallic or synthetic fibers added in different amounts. Some of the properties evaluated were: consistency of freshly mixed concrete by Abrams cone, compressive strength, flexotraction strength and indirect tensile strength. The results show a substantial improvement of the performance of the steel-slag concrete when it is reinforced with fibers. It also fulfils the requirements of “depth of water penetration under pressure” test, even in the worst environmental exposure case.

Performance of Hydraulic Mixes Manufactured with Electric Arc Furnace Slag Aggregates

Electric arc furnace slag (EAFS) has for many years simply been dumped in landfill sites; over the past few decades many researchers have investigated its reuse in cement mortar and concrete. By doing so, a waste product may be converted into a useful material with added value as a substitute for natural resources, the consumption of which is also minimized. Hydraulic mixes manufactured with EAFS normally have similar or even better hardened properties than mixes manufactured with natural aggregates. One disadvantage in the use of EAFS has been the poorer workability of the mixes, due to its higher density, porosity and water absorption levels. In this research, different EAFS mixes are manufactured and their properties in the fresh and the hardened state are closely analyzed; the results were very promising. The aim of this research is to demonstrate that EAFS concrete can achieve an acceptable workability at the correct dosages.