Optimal performance characteristics of mortar incorporating phase change materials and silica fume

This paper examines, the thermal performance of 20 different mortar mixes, which were prepared in order to study the behaviour of mortar incorporating Phase Change Materials (PCM). The PCM were was used at a rate of 10, 20 and 30% by weight of total solid materials. Silica fume was added to the mixes by 10, 20, 30 and 50% by weight of cement to enhance the mortar properties. Mortars which incorporate phase-change materials (PCM) have the capability to help regulate the temperature inside buildings, contributing to the thermal comfort while decreasing the amount of mechanical heating and cooling energy required, therefore they have the potential to reduce building carbon emissions. The mechanical characteristics and physical properties of the mortar with PCM were studied. The results show that mortar with Phase Change Materials up to PCM20% can be used with an optimal compressive strength. Silica fume (SF), up to a 20% SF addition, enhanced the mechanical properties of the mortar

Comparison between Utilization of Industrial Waste Steel Slag as Aggregate and Natural Aggregate in Underwater Self-compacting Concrete

An environmentally friendly approach to the disposal of waste materials, a difficult issue to cope with in today’s world, would only be possible through a useful recycling process. Steel slag is a byproduct of metal smelting and hundreds of tons of it are produced every year all over the world in the process of refining metals and making alloys. Coarse aggregate is one of these factors that have a significant influence on underwater self-compacting concrete (UWSCC). The work involves three groups with the total number of twenty seven underwater-concrete mixes. First group uses gravel, the second group uses steel slag, and the third group uses crushed dolomite. The test program was designed and arranged to consider the effect of four different parameters as follows; water binder ratio (w/p), high range water-reducing (HRWR) dosage, fine to coarse aggregate ratio and maximum size aggregate. The concrete mixtures were tested for slump, slump flow, slump flow time (T-500), V-funnel, L-box, GTM screen stability, washout loss method that is the plunge test CRDC61 which is widely used in North America, and compressive strength. The results show that UWSCC with industrial waste steel slag as aggregate has higher values of compressive strength and unit weight compared to UWSCC with natural aggregate

Enhancement of concrete surface by coating with cement-based alkaline activator

The exterior surface damage of concrete is a major problem for sub-structures and super-structures which are manufactured from concrete. In recent years, the protection of concrete exterior surfaces has attracted the attention of many researchers. This paper shows that alkaline activator coating materials (AACM) are used for curing concrete exterior surfaces. The curing of the concrete exterior surface with AACM helps to significantly reduce porosity in most products of building construction materials like hardened concrete and mortar plasters when they applied to their exterior surface. A chemical reaction occurs with unreactive Portland cement on the concrete exterior surface that always binds silicates to the concrete surface which in turn leads to decrease sucking of water into the concrete exterior surface. AACM can penetrate with the concrete exterior surface which helps to increase the deepness of waterproofing applied to the concrete exterior surface. The operation is simple to use, leaves no remnant and dries in a short time. It is ideal when it’s used on the concrete exterior surface and additionally it is appropriate for types of concrete exterior faces. The results presented the positive effect of alkaline activator coating materials AACM on the visual appearance, water-absorption, water-penetration, and sulfate attack. Alkaline activator coating has the same performance, but it would be cheaper when compared to the oil-based products

Simulation of the behavior of pressurized underwater concrete

Under-Water Concrete (UWC) contains Anti-Washout Admixtures (AWA) (0.0%, 0.2%, 0.3%, 0.4% and 0.5%) by weight of cement with cement contents (400, 450, 500 and 550 kg/m3). All concrete mix contains silica fume and high-range water reducing (15% and 4%) respectively by weight of cement. The fine to steel slag coarse aggregate was 1:1. The concrete mix was tested for slump, slump flow, compressive strength and washout resistance using two test methods based on different principles. The first method is the plunge test CRDC61 which is widely used in North America, and the second method is the pressurized air tube which has been manufactured for this research and developed to simulate the effect of water pressure on washout resistance of underwater mix. The results of compressive strength test were compared to concrete cast underwater with that cast in air. Test results indicated that the use of an AWA facilitates the production of UWC mix with the added benefit of lower washout resistance. New technique of simulating pressurized UWC is reliable for detecting UWC properties. Adding AWA (0.3–0.5%) by weight of cement makes all mix acceptable according to Japanese Society of Civil Engineers

Disposal of wooden wastes used as heavy metal adsorbents as components of building bricks

The recovery of wastes is the basis of the Circular Economy. In recent years, there is an increased interest in the use of agro-industrial wastes as simple and ?low-cost? adsorbents in the removal of heavy metals from wastewaters. However, the fate or reuse of such adsorbents saturated with pollutants has not been discussed deeply. The novelty of this paper is the valorization of pine sawdust waste and pine sawdust char, previously used as adsorbents for Ni(II), Zn(II), Cd(II) and their mixture, in the manufacture of porous fired clay bricks, which are an important kind of bricks due to their low weight and low thermal conductivity. Initially, both residues were evaluated as potential adsorbents for the heavy metals under study. The obtained results were much better for biochar with adsorption efficiencies close to 100%, both in individual and mixed systems, the later closer to real wastewater cases. Finally, 20% by volume of the contaminated biomass waste was incorporated into ceramic matrices, increasing the apparent porosity with respect to a brick of reference. The evaluation of the physical properties and their mechanical characterization, determined a decrease in the quality of these bricks even still within the current regulations for construction purposes. The s-s curves showed differences in the mechanical behavior associated with the type of waste material, being those obtained for bricks with biochar similar to those of the bricks of reference. Heavy metals immobilized in the clay matrix did not introduce significant changes in the physical and mechanical properties checked. Therefore, it is possible to take advantage of wood waste used as heavy metal adsorbents in wastewater treatment, with an option for its proper disposal.Fil: Simón, Daiana Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Gass, Sebastian Emiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Palet, Cristina. Universitat Autònoma de Barcelona; EspañaFil: Cristobal, Adrian Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin