Stormwater Harvested from Permeable Pavements as a Means to Save Potable Water in Buildings

The main objective of this work is to analyse the potential for potable water savings in university buildings by using stormwater collected from permeable pavements. Six buildings located on the campus of the Federal University of Santa Catarina (UFSC) were selected to obtain monthly water consumption patterns and parking lot areas. The same six buildings were then evaluated considering their location in eight different cities in Brazil, with different rainfall patterns. Simulations using the computer programme Netuno were run to obtain the potential for potable water savings in each building and city combined. The structural design of permeable pavements was also assessed using two methods available in the literature, that is, the American Association of State Highway and Transportation Officials (AASHTO) and Brazilian Portland Cement Association (ABCP). The hydrological-hydraulic design of the permeable pavement was also carried out. The designed thicknesses were compared with the thicknesses obtained using the computer programme Permeable Design Pro. The potential for potable water savings between 18.4% and 84.8% was obtained, depending on the city, building and non-potable water demand considered. For the structural design, the thicknesses obtained by using both methods were similar; however, it was observed that the AASHTO method better represents the pavement model. Regarding the hydrological-hydraulic design, the differences obtained show that the simplification performed for the pavement drainage was in favour of safety. In conclusion, the use of permeable pavements in stormwater harvesting systems is promising, aligning the drainage aid, structural capacity and potential for saving potable water.

Portland clinker with civil construction waste: influence of pellet geometry on the formation of crystalline phases

Efforts to reduce greenhouse gas emissions in the context of sustainable development have intensified, with the development of research aimed at the production of new materials and binders for construction. This article analyzes the influence of pellet geometry in the production of clinkers, with the incorporation of construction waste (CCW). Procedures adapted from the method proposed by Brazilian Portland Cement Association were adopted in studies of laboratory clinkers, in an attempt to simulate the stages of the industrial process. Pellets were prepared with the same formulation, however, with four different geometries: spherical, with diameters of 1 cm, 2 cm and 3 cm, with manual molding, and semi-spherical, with a diameter of 2 cm, using molds of PLA (polylactic acid) printed on a 3D printer to facilitate the molding of the clinkers in a standardized way. Clinkers were characterized mineralogically by x-ray diffraction (XRD) and the Rietveld method was used to quantify the phases. Variations in the quantities of the alite and belite phases were observed depending on the geometry of the pellets, although the same calcination conditions were used. This is probably due to the variation in the surface area (exposure area) and the gradients of the cooling rate.

Análisis comparativo de mezclas suelo cemento modificadas con materiales no biodegradables. Metodología de la portland cement association

Este artículo presenta el análisis comparativo de investigaciones realizadas en la Universidad de La Salle – Colombia desde el año 2012, referente a mezclas suelo cemento modificadas diseñadas con la metodología de la Portland Cement Association [PCA] (ACI, 1997), y guiadas por el artículo 350 del Instituto Nacional de Vías [Invías] del año 2013, que refiere a las características que debe cumplir una mezcla granular mejorada con cemento para control de calidad en obra, de aplicación nacional en Colombia. Inicialmente se recopila y organiza la información de manera que se identifiquen criterios comparativos de los resultados obtenidos de mezclas suelo cemento modificadas con materiales no biodegradables, como vidrio templado, poliestireno expandido [EPS], tereftalato de polietileno [PET], polietileno de alta densidad [PEHD] y grano de caucho. Enseguida se evaluaron los resultados obtenidos de dicho análisis comparativo, cuyas variaciones en los contenidos óptimos de cemento discrepan de los rangos sugeridos de la PCA, lo que lleva a plantear una discusión sobre la aplicación de esta metodología para mezclas suelo cemento modificadas, proponiendo nuevos rangos de parámetros de control para futuras investigaciones, los cuales servirán como punto de partida para proponer una nueva metodología de diseño en mezclas suelo cemento empleando dichos materiales. Sin embargo, el análisis aquí mostrado evidencia la necesidad de enriquecer con un mayor número de datos las recomendaciones que se presentan, para dar validez soportado en un procesamiento estadístico suficiente.

FLEXURAL STRESS ANALYSIS OF RIGID PAVEMENTS USING AXI-SYMMETRIC AND PLANE STRAIN FEM

The design of pavement involves a study of soils and paving materials, their response under load for different climatic conditions. In the present study, an attempt has been made to compare stresses predicted using two finite element analyses. First analysis is based on the twodimensional plane strain assumption where as in second approach axi-symmetric condition is assumed to consider three-dimensional behavior of rigid pavement. The results are compared with flexural stresses obtained from conventional Portland Cement Association method. The computed flexural stresses obtained from axi-symmetric condition are found to be in close agreement with PCA method. Results of plane strain analysis show a fair agreement after application of an appropriate multiplication factor

BETON STRUKTURAL MENGGUNAKAN AGREGAT PASIR - BATU ALAM

<p>Kuat tekan beton, selain dipengaruhi oleh mutu perekat (semen), juga ditentukan oleh mutu agregat yang digunakan sebagai bahan pengisinya. Hal ini terlihat dari komposisi agregat dalam campuran beton mencapai 60% – 75% dari total volume beton. Penggunaan agregat pasir-batu alam (sirtu) tidaklah lazim dalam pembuatan beton struktural. Namun demikian, pada pembangunan beberapa ruko/toko berlantai 2 dan 3 di kota Lhokseumawe ditemukan penggunaan sirtu sebagai agregat untuk beton.Sirtu adalah jenis batuan sedimen yang merupakan campuran kerikil dan pasir yang terjadi secara alami. Penelitian ini ditujukan untuk mendapatkan faktor air semen (FAS) pada campuran beton agregat sirtu agar dicapai mutu beton struktural minimal 17 MPa dan memiliki kemudahan pengerjaan yang baik (workability). Sirtu yan g digunakan berasal dari desa Paya Rabo, kecamatan Sawang, Kabupaten Aceh Utara, dengan ukuran maksimum 19 mm. Sirtu ini terdiri dari 73% - 86% pasir dan 14% - 27% kerikil. Semen yang digunakan merek Andalas tipe I. Jumlah sampel beton agregat sirtu yang di uji pada umur 28 hari adalah sebayak 15 buah sampel silinder(150x 300)mm, yang terdiri dari 5 sampel untuk masing-masing FAS 0,58; 0,54; dan 0,47. Sebagai pembanding digunakan 5 buah sampel yang dibuat untuk beton normal dengan FAS 0,58. Rancangan campuran digunakan metode absolute volume dari Portland Cement Association (PCA). Dari hasil pengujian diperoleh kuat tekan beton normal pada umur 28 hari mencapai 24,57 MPa. Pada umur pengujian yang sama, untuk beton sirtu, kuat tekan yang diperoleh untuk masing-masing FAS 0,58; 0,54; dan 0,47 adalah sebesar 17,09 MPa, 23,37 MPa, dan 27,61 MPa. Pada FAS 0,58 dan 0,54 beton agregrat sirtu mengalami penurunan kuat tekan masing-masing sebesar 33,4% dan 4,90% dibanding beton normal. Untuk memperoleh beton agregat sirtu dengan kekuatan 17 MPa, dilakukan interpolasi linier dari hasil pengujian tersebut dan didapat FAS sebesar 0,55. Dari hasil pengujian menggunakan FAS 0,55 didapat kuat tekan rata-rata beton agregat sirtu sebesar 21,60 MPa, dengan slump sebesar 79mm</p><p><br /><strong>Kata kunci:</strong> sirtu (pasir-batu), faktor air semen, slump, kuat tekan, beton struktural</p>

A novel finite element method for designing floor slabs on grade and pavements with loads at edges

<p class="Abstractandkeywordscontent">In the present paper a methodology to design slabs on grade for industrial floors and pavements using bi-dimensional finite elements and integrating the subgrade in the design is presented. The suggested method to design slabs on grade for industrial floors and pavements has been called the Camero Finite Element Method. An example of an industrial floor designed to be capable of sustaining an infinite number of load applications (or a 50 years lifespan period) is here presented in order to be compared with the results of the Camero Finite Element Method, the PCA (Portland Cement Association), and the WRI’s (Wire Reinforcement Institute) simplified methods. In this example, an industrial floor is designed to be capable of sustaining an infinite number of load applications comparing the results of the Camero Finite Element Method and the simplified methods of the PCA and WRI. The industrial floor or pavement will be able to resist an infinite number of load applications if it is designed with the Camero Finite Element Method. On the other hand, if it is designed using the PCA and the WRI methods, it will last a few years (in this example, in one year period, the number of axle load applications is equal to the number of allowable repetitions). To conclude, if an industrial floor o pavement is designed with the Camero Finite Element Method, it will be able to sustain an infinite number of load applications (up to 50 years lifespan period).</p>