Microstructural Study of the Interfacial Transition Zone in Concrete using Optical Microscopy

This paper presents an overview on the optical microstructural features in concrete. Microstructure is the small scale structure of a material, defined as the structure of a prepared surface of material as revealed by a microscope. The concrete specimens with the manipulation of water/cement ratio 0.3-0.7 (increment of 0.1) in the concrete mix design were used to study the optical microstructural features in concrete and to validate the existence of an interfacial transition zone (ITZ) in concrete. USB Digital Microscope is used to analyse the formation mechanism of microstructure in concrete where the optical microstructural images is analyse via respective curing periods of 1, 7, 28 and 56 days. The microstructure features are discussed with respect to their influence on the strength development of concrete

Exploring OpenMP Accelerator Model in a real-life scientific application using hybrid CPU-MIC platforms

Proceedings of: Third International Workshop on Sustainable Ultrascale Computing Systems (NESUS 2016). Sofia (Bulgaria), October, 6-7, 2016.The main goal of this paper is the suitability assessment of the OpenMP Accelerator Model (OMPAM) for porting a real-life scientific application to heterogeneous platforms containing a single Intel Xeon Phi coprocessor. This OpenMP extension is supported from version 4.0 of the standard, offering an unified directive-based programming model dedicated for massively parallel accelerators. In our study, we focus on applying the OMPAM extension together with the OpenMP tasks for a parallel application which implements the numerical model of alloy solidification. To map the application efficiently on target hybrid platforms using such constructs as omp target, omp target data and omp target update, we propose a decomposition of main tasks belonging to the computational core of the studied application. In consequence, the coprocessor is used to execute the major parallel workloads, while CPUs are responsible for executing a part of the application that do not require massively parallel resources. Effective overlapping computations with data transfers is another goal achieved in this way. The proposed approach allows us to execute the whole application 3.5 times faster than the original parallel version running on two CPUs.This research was conducted with the support of COST Action IC1305 (NESUS), as well as the National Science Centre (Poland) under grant no. UMO-2011/03/B/ST6/03500. The authors are grateful to the Czestochowa University of Technology for granting access to Intel Xeon Phi coprocessors provided by the MICLAB project no. POIG.02.03.00.24-093/13 (http://miclab.pl)

Cement and concrete production using white waste glass from recycled bottles

Większość badaczy skupia się na wykorzystaniu szkła odpadowego jako częściowego zamiennika kruszywa drobnego do materiałów o matrycy cementowej. W pracy zaproponowano alternatywny sposób zagospodarowania szkła odpadowego w przemyśle betonowym, a mianowicie jako dodatek do betonów w postaci drobno zmielonej mączki szklanej oraz jako składnik cementów. Rozdrobnione do postaci mączki szklanej odpadowe szkło dozowano do betonów w ilościach 5 i 10% masy cementu, redukując równocześnie taką samą ilość kruszywa drobnego. Wykonano dla trzech betonów (w tym beton referencyjny) badania: wytrzymałości na ściskanie, głębokości penetracji wody oraz nasiąkliwości. Wstępnie rozdrobnione szkło odpadowe, pochodzące z białych butelek wspólnie, zmielono także z wcześniej wypalonym klinkierem portlandzkim. Szkło było dozowane w ilościach 6 i 12% masy klinkieru. Uzyskano w ten sposób dwa rodzaje cementów z dodatkiem szkła odpadowego oraz cement referencyjny, dla których wykonano badania: wytrzymałości na ściskanie po 2, 7, 14, 28 i 90 dniach, początku czasu wiązania cementu oraz jego stopnia zmielenia. Przeprowadzona analiza uzyskanych wyników badań potwierdziła możliwość innego zagospodarowania stłuczki szklanej niż dotychczas w większości proponowane. Betony z udziałem rozdrobnionego szkła z butelek uzyskały zadowalające wyniki wytrzymałości na ściskanie, nasiąkliwości oraz penetracji wodą. Cementy uzyskane ze wspólnego zmielenia ze szkłem odpadowym charakteryzowały się znacznie lepszymi parametrami mechanicznymi w porównaniu do cementu referencyjnego.Most researchers focus on using waste glass as a partial replacement for fine aggregate in the cement matrix. This article proposes an alternative method of managing waste glass in the concrete industry, as an addition to concrete in the form of finely ground glass powder and as a component of the cement. Waste glass ground into a glass powder was dosed into concrete in quantities of 5 and 10% of the weight of cement while reducing the same amount of fine aggregate. Tests that were carried out on three concretes (including a control concrete) included compressive strength, water penetration depth and water absorption. Pre-shredded waste glass from white bottles was also ground together with previously burned Portland clinker. The glass was dosed in quantities of 6 and 12% of the weight of clinker. In this way, two types of cement were obtained: cement with the addition of waste glass and the control cement. Tests carried out included compressive strength after 2, 7, 14, 28 and 90 days, the beginning of cement setting time and its grinding degree. An analysis of the obtained test results confirmed the possibility of using waste glass in a way other than previously proposed. Concretes including fragmented glass from bottles have obtained satisfactory results of compressive strength, water absorption and penetration. Cements obtained as a ground mixture with waste glass were characterized by much better mechanical parameters compared to the control sample cement

Designing the composition of concrete with fly ashes and their influence on increment rate of strength

W pracy przedstawiono wyniki badań oceniających wpływ popiołów lotnych na parametry mieszanek betonowych i betonów. Na podstawie przeprowadzonych badań stwierdzono, że popioły lotne są wartościowymi dodatkami do kompozytów betonowych. W przypadku zastosowania ich jako częściowego zamiennika cementu powodują spowolnienie tempa przyrostu wytrzymałości betonów w pierwszym etapie ich dojrzewania. Zastosowanie popiołów lotnych jako dodatkowego składnika betonów prowadzi do uzyskania już po 2 dniach kompozytów betonowych o wyższych wytrzymałościach w stosunku do betonów niemodyfikowanych popiołami.This paper presents guidelines for design of concrete with fly ash. Four series of concrete have been designed. Investigations of compressive strength after 2, 28 and 56 days of hardening have been conducted for each of the concrete series

Evaluation of freeze resistance of concretes modified with waste ceramics

W artykule przedstawiono analizę wpływu ceramiki odpadowej, dokonując oceny jej wpływu na wytrzymałość na ściskanie oraz odporność na cykliczne zamrażanie i rozmrażanie badanych kompozytów betonowych, wykonanych na bazie kruszywa łamanego. Badanie odporności na zamrażanie i rozmrażanie przeprowadzono tradycyjną metodą dla 150 cykli oraz przy wykorzystaniu urządzenia do automatycznej analizy obrazu, oznaczając strukturę porowatości betonu. Ceramika odpadowa była dozowana w postaci rozdrobnionego pyłu (tzw. mączki) w ilościach 5 i 10% masy cementu. Pozyskana do badań ceramika została rozdrobniona w młynie oraz dezintegratorze i pochodziła z recyklingu ceramiki sanitarnej, ściennych płytek ceramicznych oraz ceramicznych dachówek. Dodanie tak rozdrobnionej ceramiki wpłynęło na uzyskanie lepszej urabialności mieszanek betonowych.The paper presents the analysis of the impact of waste ceramics on compressive strength and resistance to cyclic freezing and thawing of tested concrete composites, made on the basis of broken aggregate. The freeze–thaw test was carried out using the traditional method for 150 cycles and using an image automatic analysis device determining the porosity structure of the concrete. The waste ceramics were dosed in the form of ground dust (so–called flour) in quantities of 5 and 10% of the cement mass. The ceramics for testing were ground in a mill and disintegrator and were obtained from the recycling of sanitary ceramics, ceramic wall tiles and ceramic roof tiles. The addition of such shredded ceramics influenced obtaining better workability of concrete mixtures

A Proposition of an In Situ Production of a Blended Cement

Many byproducts and waste materials with pozzolanic properties can substitute natural raw materials in cement production. Some of these waste materials like fly ash and blast furnace slag are commonly harnessed by cement industry. Others are of seldom use due to limitations of the very centralized cement production systems currently in use. In the authors opinion, it is necessary to change this system to enable efficient utilization of various waste materials that are available locally (e.g., white and red ceramics). In this study, a new partially centralized system of cement production is proposed. The adoption of a new system would significantly reduce the volume of long-distance transportation and enable utilization of numerous locally available waste materials that are currently dismissed. The last stage of production of the ready-to-use cement would take place in situ. The cement would be produced on demand and be immediately used for concrete production on-site. The research program was conducted considering the importance of the quality of cements obtained in the new way, substituting up to 12% of its mass by white ceramics. The research program was proof of concept of the proposed cement production system. It was shown that the quality of “in situ cement” does not differ from standard cements

Analiza wpływu popiołów lotnych na tempo przyrostu wytrzymałości i mrozoodporność betonów

The article presents the analysis of the influence of different content of fly ash on concrete durability and frost-resistance growth rate. Durability research was conducted after 2, 28 and 56 days of concrete maturation. Frost-resistance examination was conducted for 150 cycles of freezing and thawing. Frost-resistance was examined for concrete samples after 28 and 56 days.W pracy przedstawiono analizę wpływu różnej zawartości popiołów lotnych na tempo przyrostu wytrzymałości betonów oraz ich mrozoodporność. Badanie wytrzymałości wykonano po 2, 28 i 56 dniach dojrzewania. Badania mrozoodporności wykonano dla 150 cykli zamrożeń i rozmrożeń. Mrozoodporność badano dla betonów w wieku 28 i 56 dni

Application of waste from utilitarian ceramics for production of cement mortar and concrete

Preliminary results of utilization of ceramic waste for the produce of ceramic mortars and concrete have been presented. Currently, ceramic wastes from the production of ceramic flower pots and covers are not used in any form. The chemical composition of this waste materials was determined using X-ray fluorescence (spectrometer ARL Advant 'XP). Cement mortar and concrete were made using CEM I 42.5 R. The results showed that the compressive strength (after 28 days) of cement mortar increased with the increase of size reduction of the ceramic waste. The highest compressive strength (increased by 5.0% compared to the control sample) was found for cement mortars in which waste pottery with fragmentation of less than 0.2 mm were used. These mortars also showed the highest frost resistance (after 150 freeze and unfreeze cycles), whereas the largest decrease the compressive strength (over 17%) after the frost resistance test showed samples of the cement mortar with the ceramics waste fragmentation in range 1.0–3.0 mm. Studies have also shown that the compressive strength of concretes increase with added the ceramic waste (10–30%) instead of natural aggregate. The highest compressive strength (approximately 12.3%) compared with the sample control show the concrete in which 30% of the natural aggregates were replaced by the ceramics waste. Furthermore, using up to 30% of ground ceramic in the concrete reduces its water absorption capacity