Abstract

Cigarette butts are one of the most common waste worldwide. The toxic and non-biodegradable components make cigarette butts a hazardous waste and one of the causes of pollution. This paper presents some of the results of a study on the re-cycling cigarette butts in the manufacture of clay bricks. Four mixtures were made, these include a control clay brick, with a clay content of 100% (LADRICOL 0%) and three additional mixtures incorporating cigarette butts in different percentages by weight (LADRICOL 2.5%, LADRICOL 5.0% and LADRICOL 7.5%). The mixtures were fired at different temperatures and these were tested to determine the physical and mechanical properties of the bricks. The results showed that the samples incorporating 2.5% cigarette butts content and fired at 850 °C are in compliance with the standard normative for this type of product (NTC 4205-2). Furthermore, this brick can improve the environmental quality and can reduce energy consumption during firing, by 19.75%.

Abstract

The elimination of metal waste generated during the initial manufacturing processes of industrial plants and workshop machines still a big problem.  The current investigation dealt with adding the metal wastes produced by machinery processing such as iron filings powder, iron turning lathe, and aluminum turning lathe to improve the structural performance of oneway ribbed slab (RS) panels. Two types of concrete were considered in this work; Ferro cement (FER) and self-compacting concrete (SCC). The reinforced concrete panels with iron filings powder and iron turning lathe showed an increase in the ultimate load and a decrease in the central deflection, while the panels with aluminum turning lathe revealed an opposite behavior.  The significant effect of using metal wastes is the superior resistance to crack propagation by increase the bond between fibers and cement mortar across the cracks. Adding the metal wastes with fine particles improves the concrete strength providing the workability must be controlled. Using the lathe as an iron fiber with a specific shape factor has a side effect due to fiber balling in the concrete mix. Also, high percentages of filings iron powder cause agglomerate the powder particles due to magnetic attraction forces.

Abstract

Subgrade moisture variation monitoring and control is important due to its influence on road pavement performance and service life. The precise application of non-invasive techniques such as time domain reflectometry (TDR) and ground penetration radar (GPR) in compacted tropical soils depend on calibration models, that consider their mineralogical composition and geotechnical properties. The present work aims to determine calibration models that relate dielectric permittivity with moisture variation in compacted tropical soils. TDR technique was used with low-cost probes and soil calibration columns developed at laboratory for reading dielectric permittivity and define its relationship with moisture. Results showed that through laboratory standardized procedures, it is possible to determine calibration models according to the required accuracy in moisture control in the subgrade. It was found that the high density and magnetic properties of tropical soils significantly influenced the determination of dielectric permittivity and consequently in moisture estimates, hence reaffirming the need of specific calibrations for these types of soils.

Abstract

The use of Portland cement is considered a very good material for making concrete. This is because many are found in building shops and it's high performance in making concrete. Research on alternative Portland cement is a worldwide priority for reducing CO emissions to the atmosphere. Alternative Portland cement is a material containing aluminosilicate which is dissolved with an alkaline solution to produce strong pozzolanic properties and replace the function of Portland cement. Natural aluminosilicates can be found in agricultural and industrial wastes. For example fly ash (FA), roof tile ash (RTA), rice husk ash (RHA), sugar cane bagasse ash (SCBA). This method estimates the development of mechanical properties of concrete with alternative portland cement with concrete with  portland  cement throughout the treatment process. The mechanical properties that will be seen are setting time and compressive strength. Alternative Portland cement uses the basic ingredients of fly ash aluminosilicate with an alkaline activator solution (NaOH, Na2SiO3) of 12 Molar. This study is based on experimental studies by replacing FA by 5% and 10% with RHA and RTA where the development of several mechanical properties will be investigated. The results show that several alternative portland cement mixes have similar mechanical properties to portland cement.

Abstract

This paper presents the evaluation of lightweight concrete masonry blocks, incorporated with tire rubber and metakaolin, aiming reduce its bulk density and obtaining dimensional values of compressive strength and water absorption in according to the Brazilian standard ABNT NBR 6136: 2016. Three mixtures of concrete were produced by the replacement of 9%, 18% and 27% (by volume) of the fine aggregate by tire rubber, and one mixture without rubber (reference). In all mixtures the procedure of replacing 10% (by weight) of cement to metakaolin was adopted. Family M-15x30 of concrete blocks were performed using an entirely manual process, with PVC molds and PET bottle devices to casting the hollow characteristic of blocks. The results indicated that the concretes produced with rubber and metakaolin provided bulk density values lower than 2000 kg/m³, thus featuring lightweight concrete characteristics. In the dimensional verification, all the blocks series produced reached of requirements of the current standard. Although only the R0, R1 and R2 series had structural function, however all mixtures achieved water absorption ratio lower than 13%. Therefore, the tire rubber as fine aggregate in concrete masonry blocks is thought to be a good alternative for reuse of this waste material.

Abstract

Originality/value: Energy efficiency and environmental friendliness, as important principles of sustainability for multifunctional complexes, are here considered in the context of the international experience, enabling an identification of the main aspects that are applicable when designing such buildings in Ukraine. Purpose: The purpose of this article is to study the principles of improving energy efficiency and environmental friendliness of multifunctional complexes in Ukraine and thereby enrich the national experience in designing sustainable architecture. Results: On the basis of the study, scientific principles and recommendations are developed that contribute to improving the energy efficiency and environmental friendliness of such complexes. Conclusion: It is concluded that the use of alternative energy sources can cover at least 15-20% of the total energy consumption, and by optimizing the plan it is possible to increase the energy efficiency of a building by up to 14%.

Abstract

This article shows the results of a study on the evaluation of the use of the TDI (Traffic Densification Index) for the prediction of the behavior of a conventional asphalt mixture and two nano-modified asphalt mixtures (one with 2% of carbon nanotubes, CNTs, and another with 3% of organophilic nanoclay, NA) against permanent deformation. The mixtures were designed with equivalent granulometries and different asphalt binders (a conventional and two nano-modified binders). The design of the mixtures was made according to the Superpave method, and the TDI of the mixture was determined from the curves obtained in the compaction test (%Gmm vs number of cycles). For each mixture under study, two slabs measuring 50 x 18 x 5 cm were compacted on the BBPAC slabs compactor of IFSTTAR (Institut Français des Sciences et Technologies des Transports, de L'Aménagement et des Réseaux). These slabs were subsequently subjected to the permanent deformation test in the French traffic simulator, Orniéreur. The TDI obtained was compared with the performance of the mixtures in the permanent deformation test. The results obtained show that the TDI was not effective in predicting the behavior, in terms of permanent deformation, of asphalt mixtures with asphalt binders different from the conventional binder (nano-modified).

Abstract

Ferrocement panels are thin section comprised of hydraulic mortar reinforced with steel wire mesh, and are susceptible to micro cracks at service conditions. The moisture and rainwater may infiltrate through these cracks and cause the reduction in capacity due to the corrosion of steel wire mesh.  In the present study, a polypropylene (PP) wire mesh has been used to overcome this problem. The main objective of the study is to investigate the punching shear and bending capacity of the ferrocement panels using PP wire mesh. Experimental tests conducted on 32 simply supported square slabs panels of 450x450 mm subjected to concentrated load for punching shear and four-point loading to investigate the bending capacity. The test variables were the number PP layers (volume fraction ratio) and slab thickness i.e., 20, 30 and 40 mm. Test results showed that punching capacity improved by increasing both the number of PP layers and panel thickness. However, bending strength the function of tension membrane action provided by exterior PP layers. Moreover, panels with 20 mm thickness are to flimsy and do not show sufficient capacity. In general, PP wire mesh provide adequate resistance against punching and bending for slab thickness 30mm and 40mm, and can be used as replacement of conventional steel wire mesh.

Abstract

The applicability of nonlinear analysis methods: pushover (NSP) and multimodal pushover (MPA) is verified for torsionally – flexible structures whose natural vibration period is larger than 1sec. The results are confronted with a nonlinear response history analysis (NLRHA). The procedure is applied to an irregular 10-story concrete framed structure, built in the 70’s. A mathematical three-dimensional finite element-based model was developed using material properties based on Mander (1984) concrete model and Park (1975) steel model. Seismic hazard is established for the design basis earthquake with 10% probability of exceedance in 50 years; and, for 3 pair of ground motions properly matched and scaled to DBE. It was determined that for structures with 1sec or more natural vibration period, NSP underestimates the maximum displacement capacity, since it does not consider the contribution of higher vibration modes to the total response of the system. MPA fits more to NLRHA and is mainly applicable to regular framed buildings, since inconsistences are generated when a considerable percentage of torsion occurs in translational vibration modes.