Publicaciones científicas CTCON

Abstract The study evaluates self-compacting concretes where part of the limestone aggregate is replaced with granulated blast furnace slag (GBFS) at 0–60%. Early-age mixes with higher GBFS show lower compressive strength due to poorer aggregate compaction, but long-term strength increases as the slag hydrates/reacts, improving the aggregate–paste interface.

Abstract The paper evaluates concretes made with several types of recycled demolition aggregates, focusing on pore structure and sound absorption. Although recycled aggregates generally lower mechanical strength due to higher porosity, that same porosity can significantly enhance acoustic absorption. Using an image-analysis methodology (novel in this context) alongside density and acoustic measurements, the study shows recycled-aggregate concretes can match or outperform conventional concretes in sound absorption, offering an environmentally beneficial alternative for noise-mitigating elements.

Abstract Experimental study on vibro-pressed precast concretes (e.g., pipes) where part of the Portland cement is replaced by natural diatomite and recycled diatomites from beer/wine filtration, both uncalcined and calcined. Mechanical strength, capillary absorption, carbonation, and chloride ingress were assessed. The results show industrial feasibility of both natural and recycled diatomites, with potential improvements in long-term properties; calcination enhances performance versus uncalcined material.

Abstract Se estudia el uso de dos agentes “self-healing” en morteros—nitrato cálcico (NC) y silicato sódico (MSS)—para promover la mineralización en fisuras y mejorar la durabilidad. El programa incluye caracterización de materiales, resistencia a compresión (7/28/90 días), carbonatación acelerada, penetración de cloruros y análisis microestructural (SEM y porosimetría por intrusión de mercurio). Los resultados muestran que el NC (3–6% s/cemento) incrementa la resistencia a compresión y favorece la formación de productos de curado (p.ej., etringita y carbonatos) que sellan fisuras, con mejoras asociadas de durabilidad. El MSS potencia la autocuración pero penaliza las resistencias mecánicas respecto al testigo. En conjunto, el NC se perfila como el agente más efectivo para compatibilizar autocurado y prestaciones mecánicas..

Abstract Industrial-scale paving blocks were produced using four recycled construction-and-demolition aggregates (C&DW) under standard factory conditions, with optimized dosages and three mix designs. Mechanical evolution, service properties and ionic leaching were assessed; data were analyzed with principal component analysis (PCA). Results indicate that most recycled aggregates can replace ~25% of natural aggregate in vibro-pressed precast concrete while meeting UNE-EN 1338 performance requirements. All blocks were environmentally safe per the Netherlands Soil Quality Decree (no leaching risk), supporting industrial uptake of recycled aggregates in non-structural concrete.

Abstract The work studies recycled aggregates that contain gypsum—common in C&DW—and their effect on mortar performance when combined with different binders: Portland cements (CEM I, CEM III/B, CEM IV) and alkali-activated slag (AAS). Gypsum contents of 2%, 5%, 10%, and 20% (replacing natural aggregate) were assessed via compressive and flexural strength, ultrasonics, and dimensional stability. Up to ~2% gypsum, behavior is comparable to reference mixes across all binders. Above that threshold, responses diverge by cement type; with CEM III/B and CEM IV the measured properties are least affected, whereas higher gypsum tends to be more detrimental in other systems