Self-Compacted Clay Based Concrete (SCCC): Proof-of-Concept

ISSN:0959-652

Alkali-activated binder containing wastes: A study with rice husk ash and red ceramic

In addition to several positive aspects in technical properties, geopolymeric binders have considerable advantages in the environmental point of view, with lower energy consumption and lower CO2 emission. In this study, it was conducted an overview about the utilized materials by some Brazilian researchers in geopolymers production, and also an experiment employing two types of wastes (red ceramic waste and rice husk ash). The compressive strength of the resulting material developed very fast, reaching a value of 11 MPa after one day. The microstructure was evaluated by scanning electron microscopy, revealing a compact microstructure and the presence of starting materials from the red ceramic waste that not completely reacted. The results indicated the feasibility of producing geopolymeric material without using commercial sodium silicate and cured at room temperature, showing an option for building materials production with lower environmental impacts.ISSN:0366-691

Effect of fluorite addition on the reactivity of a calcined treated spent pot lining in cementitious materials

Treating SPL by the low caustic leaching and liming process generates an inert nonhazardous residue called LCLL Ash and a fluorite byproduct Calcined LCLL Ash that is ground into a fine powder demonstrates pozzolanic behavior in cement. The effect of the calcination temperature and fluorite byproduct addition on the reactivity of LCLL Ash was studied by the compressive strength activity index, Frattini test and Rilem R3 tests followed by XRD analysis. At 800°C, the formation of nepheline causes alkali uptake, the LCLL Ash showed a slightly lower reactivity with 10% fluorite addition. At 1000°C, calcined LCLL Ash/CF showed a better amorphization of phases and increasing reactivity due to reactions between fluorite and sodium oxide. Unlike LCLL Ash, no delay in hydration or hydro reactivity was observed with calcined LCLL Ash/CF

Combined Experimental and Computational Prediction of the Piezoresistivity of Alkali-Activated Inorganic Polymers

The incorporation of smart building materials into construction will improve the working life of structures and infrastructure around the globe. Unfortunately, conventional smart building materials are cost-prohibitive because of the self-sensing additives required. Alkali-activated inorganic polymers are a promising low-cost and environmentally friendly alternative that exhibit intrinsic self-sensing properties, without the need for self-sensing additives. An improved methodology has been developed to quantify the self-sensing piezoresistivity of these materials. Experimental measurements reveal a strong intrinsic piezoresistivity up to 12%. The results agree with a first-principles model of the theoretical piezoresistivity of an alkali-activated inorganic polymer from the quantum mechanical perturbation theory. This first-of-its-kind computation provides a mechanistic explanation for the origin of intrinsic piezoresistivity in inorganic polymers

Robust Superhydrophobic Cotton Fibers Prepared by Simple Dip-Coating Approach Using Chemical and Plasma-Etching Pretreatments

The preparation of superhydrophobic textiles with high mechanical and chemical durability is challenging. Here, facile and fluorine-free methods, using alkali and plasma-etching treatments, followed by the addition of silica nanoparticles and tetraethyl orthosilicate (TEOS), were used to prepare superhydrophobic cotton surfaces. With different input variables and etching techniques, superhydrophobic cotton fabrics with high chemical and mechanical durability were successfully prepared, with contact angles up to 173°. A control of the surface architecture at the nanoscale in combination with a homogeneous repellent layer of TEOS in the cotton surface was achieved. The repellent properties of the as-prepared cotton remain stable under accelerated laundering and abrasion test conditions. The etching pretreatment by alkali or plasma plays a key role in obtaining superhydrophobic cotton surfaces

Carbon footprint assessment of a wood multi-residential building considering biogenic carbon

Wood and other bio-based building materials are often perceived as a good choice from a climate mitigation perspective. This article compares the life cycle assessment of the same multi-residential building from the perspective of 16 countries participating in the international project Annex 72 of the International Energy Agency to determine the effects of different datasets and methods of accounting for biogenic carbon in wood construction. Three assessment methods are herein considered: two recognized in the standards (the so-called 0/0 method and −1/+1 method) and a variation of the latter (−1/+1* method) used in Australia, Canada, France, and New Zealand. The 0/0 method considers neither fixation in the production stage nor releases of biogenic carbon at the end of a wood product's life. In contrast, the −1/+1 method accounts for the fixation of biogenic carbon in the production stage and its release in the end-of-life stage, irrespective of the disposal scenario (recycling, incineration or landfill). The −1/+1 method assumes that landfills offer only a temporary sequestration of carbon. In the −1/+1* variation, landfills and recycling are considered a partly permanent sequestration of biogenic carbon and thus fewer emissions are accounted for in the end-of-life stage. We examine the variability of the calculated life cycle-based greenhouse gas emissions calculated for a case study building by each participating country, within the same assessment method and across the methods. The results vary substantially. The main reasons for deviations are whether or not landfills and recycling are considered a partly permanent sequestration of biogenic carbon and a mismatch in the biogenic carbon balance. Our findings support the need for further research and to develop practical guidelines to harmonize life cycle assessment methods of buildings with bio-based materials.This publication has received funding from the Swiss Federal Office of Energy (grant number SI/501549-01); the European Union’s Interreg 2 Seas 2014–2020 Programme under grant number 2S05-036 CBCI; the French Agency for Ecological Transition (ADEME); in Germany, from Project Management Organisation Jülich (Projekttr¨ ager Jülich: PtJ) and the German Federal Ministry for Economic Affairs and Energy (Bundesministerium für Wirtschaft und Energie: BMWi) (grant number 03ET1550A); the Danish Energy Agency under the Energy Technology Development and Demonstration Programme (grant 64012-0133 and 64020-2119);in Austrian by the Austrian Ministry for Transport, Innovation and Technology (BMVIT) via IEA Research Cooperation via the Austrian Research Promotion Agency (FFG) Grant #864142; the Czech Ministry of Education, Youth and Sports within and within project Interexcellence No. LTT19022; Natural Resources Canada and Quebec Wood Export Bureau (QWEB)