Este trabalho apresenta uma análise do comportamento da frente de carbonatação em vigas de concreto armado sob tensão, em escala natural e reduzida, com a máxima condição de subarmação. As vigas foram construídas com e sem adição da sílica da casca de arroz e sílica de ferro silício ou silício metálico. Para cada viga em escala natural (agregado graúdo com D máx. = 19 mm) foi moldada uma em escala reduzida com o mesmo traço de concreto para estabelecer os mesmos parâmetros de comparação. As vigas foram curadas durante 7 dias e posteriormente submetidas à flexão, com o carregamento aplicado nos terços (L/3 da viga). Realizou-se o pré-condicionamento para a estabilização da umidade interna das vigas que foram expostas durante 28 dias em um ambiente com concentração de 50% de dióxido de carbono, umidade relativa de 65 \'+ OU -\' 5% e temperatura ambiente. Foram determinados: resistências à compressão simples axial, resistência à tração por compressão diametral, módulos de elasticidade e profundidade da frente de carbonatação em corpos-de-prova cilíndricos. A profundidade da frente de carbonatação em corpos-de-prova foi determinada para diferentes concentrações de dióxido de carbono. Também foi verificada a carbonatação ao longo das vigas em escala natural e reduzida e nas posições das fissuras. Para a previsão da profundidade da frente de carbonatação nas vigas, foram ajustadas equações para a representação da carbonatação na região das fissuras. Os resultados obtidos mostraram a eficiência da espessura do cobrimento, a eficácia dos modelos físicos reduzidos para realizar estudos de carbonatação e a tendência da carbonatação em elementos estruturais na condição de serviço. A frente de carbonatação difere na posição das fissuras, evidenciando um comportamento diferente quando comparado com corpos-de-prova. A análise microestrutural ilustrou o comportamento da frente de carbonatação em vigas de concreto armado, complementando o estudo experimental. Com base nos resultados obtidos pode-se afirmar que a simples adoção de concretos de alto desempenho para construção de elementos estruturais não é suficiente nas peças que contenham fissuras e que sejam submetidas a atmosferas ambientais agressivas. / This work reports on the behavior of carbonation in reinforced concrete beams under stress regime on full and small scales having the lowest possible frame. The beams were made with and without adding silica from rice husk and silica fume (Fe-Si). For each beam on a full scale (coarse aggregate with D máx. = 19 mm) another beam on a small scale was made with the same mix of concrete to maintain the same comparison parameter. The beams were cured for 7 days and subsequently submitted to flexure by applying a two-point loading (L/3 of beam). Humidity stabilization to stabilize internal humidity of beams exposed for 28 days in an environment with a concentration of 50% carbon dioxide, 65 \'+ OR -\' 5% of relative humidity and room temperature was carried out. The following was determined: axial compression strength, tensile splitting strength, young\'s modulus and carbonation depth in cylindrical specimens. The carbonation depth was determined in specimens with unlike carbon dioxide concentration. Moreover, carbonation along beams on full and small scales and in cracks was observed. To estimate the carbonation depth of the beams, equations were adjusted to represent the carbonation in cracks. The results show the efficiency in the thickness of the cover, efficiency of small-scale models for studies concerning carbonation and behavior of carbonation in the serviceability of structural elements. The carbonation depth differs in the position of cracks, showing behavior which is unlike the one compared to specimens. The microstructure analyses show the behavior of carbonation depth in reinforced concrete beams complementing the experimental study. The results show that it is not sufficient to use high performance concretes in structural elements for elements with cracks and in aggressive atmospheres.

Com este projeto obteve-se informações sobre o comportamento de pilares submetidos à compressão excêntrica, executados com concreto de alta resistência, com resistência média à compressão de 80 MPa. Os pilares tinham seção transversal retangular de 15 cm x 30 cm, com altura livre de 174 cm. A excentricidade da força foi de 38 cm com plano de ação do momento paralelo ao menor lado. Foram ensaiados seis pilares, onde as variáveis foram as taxas de armaduras transversais e longitudinais. Os pilares foram ensaiados sob a ação de duas forças aplicadas de modos independentes, para maior precisão e controle do posicionamento da força excêntrica. Uma força era aplicada na direção do eixo longitudinal do pilar e outra, paralela a esse, com excentricidade definida. Foram montados dispositivos de vinculações e mecanismos de transferências de forças nos pilares, procurando aproximar as situações de ensaios às do modelo teórico pretendido. As rotações eram liberadas nas extremidades dos pilares, e a seção localizadas na meia altura comportava-se sob flexo compressão reta com pequena excentricidade. Os pilares com menor taxa de armadura transversal, tiveram ruptura frágil da seção transversal central com flambagem das barras das armaduras longitudinais. Os pilares com maior taxa de armadura transversal, apresentaram ruptura com boa ductilidade e esmagamento do concreto do lado mais comprimido. As deformações lidas nas barras das armaduras do lado mais comprimido, no instante da ruptura, ficaram entre 2,3% e 3%. Utilizaram-se modelos teóricos propostos na literatura para obter os valores estimados das forças normais últimas e momentos fletores últimos, comparando-os com os encontrados experimentalmente. / This work presents a study of the behavior of high strength columns under eccentric compression, with concrete cylinder compressive strength of around 80 MPa. The columns studied had cross section area of 15 cm x 30 cm at the test region, and an effective length of 174 cm. The eccentricity of the load was 380 mm and the plan of action of the moment was parallel to the smallest side of the cross section. Six columns were tested. The main variables were the stirrup volumetric ratio and the longitudinal steel ratio. The columns were tested under the action of two independent loads, an axial load and an eccentric load, so that could be precise the positioning of the eccentric load and the control of this action. The axial load was applied on of the longitudinal axis of the columns and the eccentric load was applied with the defined eccentricity. Articulation devices and load application devices were mounted such as to approach the proposed theoretical model as much as possible. The rotations were liberated in the extremities of the columns, and the section behaved under eccentric compression. The columns with smaller stirrup volumetric ratio showed a brittle mode of failure occurring at the central cross section accompanied by the buckling of the longitudinal reinforcement. On the other hand, the columns with larger stirrup volumetric ratio presented ductile failure accompanied by crushing on the most compressed side of the column. The measured longitudinal reinforcement strain on the most compressed side of the columns at the instant of failure were between 2,3% and 3%.Theoretical models proposed in literature were used to obtain values of the maximum axial load and ultimate flexural moment and the result compared with experimental results obtained in the tests.

A premissa básica para se ter concreto armado é a existência de aderência entre o concreto e o aço. Vários fatores influenciam o comportamento da aderência, o que torna o fenômeno complexo. Em contraste como nível de informações sobre o comportamento da aderência, não existem resultados suficientes quanto à aderência em concreto de alto desempenho (CAD) e o efeito da adição repetida no comportamento da ligação aço-concreto. Neste contexto, o objetivo principal deste trabalho foi analisar a aderência em CAD sob ação repetida. Foram realizados ensaio das quatro barras e arrancamento e desenvolvido método de instrumentação interna de barras. Foram analisadas duas séries de ensaios de arrancamento, que diferiam no grau de confinamento máximo da amplitude. Outro ponto que teve especial atenção foi a distribuição de tensões de aderência. Verificou-se que o comportamento da aderência em CAD é qualitativamente o mesmo de concretos usuais. Entretanto, devido à natureza frágil do CAD, mesmo em concreto confinado, a pintura dos modelos foi por fendilhamento. Quanto à distribuição de tensões de aderência, a aplicação de um carregamento repetido prévio não afeta a distribuição de tensões, alterando somente a ordem de grandeza das tensões alcançadas durante o andamento do ensaio. / The basic premise for having reinforced concrete is the existence of bond between concrete and steel. Various factors influence the behaviour of the bond, which makes the phenomenon complex. In contrast with the level of information about the behaviour of the bond, there are insufficient results concerning bond in High Performance Concrete (HPC) and the effect of repeated action on the behaviour of the steel-concrete ligation. In this context, the main objective of this work was to analyse the bond in HPC under repeated action. Controlled tests were carried out, four bars and pullout and a method of internal instrumentation of the bars was developed. Two series of pull-out test were analysed, which differed in the degree of bar confinement. In reference to repeated action, the number of cycles and the level of maximum load of amplitude were analysed. Another aspect which had special attention was the distribution of bond stress. It was verified that the behaviour of the bond in HPC is qualitatively the same as normal concrete. However, due to the brittle nature of HPC, even in confined concrete, the failures of the models were by splitting. In reference to the distribution of bond stress, the application of a previously repeated load does not affect the distribution of stress, altering only the order of magnitude of the reached stress during the testing.

O uso de adições minerais no concreto como substituição parcial ao cimento Portland ajuda a preservar os recursos naturais poupando a matéria-prima, reduzindo o consumo de energia necessária para a produção do cimento e reciclando rejeitos que se lançados no meio ambiente causariam problemas ambientais e de saúde pública. A adição mineral que vem tendo muito destaque devido à sua alta reatividade, considerada por vários pesquisadores como uma superpozolana, é a sílica ativa (SA), um subproduto da fabricação de silício metálico ou ligas de ferro-silício. A sílica ativa se caracteriza por uma elevada finura e alta área específica e um alto teor de sílica vítrea, estes fatores somados garantem à SA a alta reatividade com o hidróxido de cálcio, transformando-o em silicato de cálcio hidratado. A casca do arroz vem sendo pesquisada como uma fonte alternativa de sílica ativa. A sílica ativa extraída da casca de arroz contém um alto teor de SiO2 e, dependendo do processo de extração, possui propriedades adequadas para a utilização na confecção de concretos de elevado desempenho. Este trabalho visa estudar a atividade pozolânica da sílica da casca de arroz produzida no laboratório de materiais avançados à base de cimento. Para avaliar as características das sílicas, foram realizados ensaios tanto para determinação das suas propriedades físicas quanto para a determinação de sua composição química e pozolanicidade. Os ensaios realizados foram:composição química, pozolanicidade (método Chapelle modificado), área superficial B.E.T., distribuição granulométrica, distribuição do tamanho de partículas via MEV, amorficidade (por difratometria de raio X), massa específica e determinação do índice de atividade pozolânica com cimento Portland (NBR-5752). Os ensaios de caracterização demonstraram que a sílica da casca de arroz possui um alto grau de amorficidade e elevada área superficial, que garantiram uma maior reatividade nas idades iniciais, porém em idades avançadas apresentou a mesma eficiência que a sílica de ferro-silício. / The use of mineral additions in concrete in order to partially replace Portland cement helps to protect natural resources by saving raw material, reducing energy consumption in cement production and recycling industrial waste that could otherwise cause environmental and public health hazards. One mineral addition that has drawn considerable attention due to its high reactivity is silica fume (SF), a byproduct of the manufacturing process of metallic silicon or iron-silicon alloys and considered by many researchers as a superpozzolan. Silica fume is characterizated by high fineness, high specific area and high content of vitreous silica. The sum of these factors provides SF high reactivity with calcium hydroxide, which is transformed into hydrated calcium silicate. Rice husk ash has also been investigated as an alternative source of silica fume. The silica from rice husk ash contains a high percentage of SiO2 and, depending on the extraction process, has adequate properties to be employed in the manufacturing of high-performance concrete. The objective of this work is to study the pozzolanic activity of silica from rice husk ash produced at the Laboratório de Materiais Avançados à Base de Cimento. In order to evaluate the characteristics of silica samples from rice husk, assays were performed to determine their physical properties as well as their chemical composition and pozzolanicity. The assays performed were: chemical composition,pozzolanicity (modified Chapelle method), B.E.T. surface area method, granulometric distribution, particle size distribution by Scanning Electron Microscope (SEM), amorphicity by X-ray diffractometry (XRD), specific mass and pozzolanic activity index determination with Portland cement (NBR-5752). The characterization assays showed that the silica from rice husk ash has a high amorphicity level and a high surface area, which yield higher reactivity at initial ages. However, at advanced ages it pesented the same efficiency as that of silica from iron-silicon.

Made available in DSpace on 2014-07-29T15:03:41Z (GMT). No. of bitstreams: 1 Dissertacao Simone Ataide Beserra.pdf: 2438283 bytes, checksum: abbcdf2cacf8c82fb112904e30a3c176 (MD5) Previous issue date: 2005-06-07 / In the case of conventional concrete, small constructive defects, variations of mix proportion or even inadequate curings can not compromise significantly the material. No longer HPC demands a severity in the control since its dosage until the execution, therefore any imperfection can bring serious damages to the material or the structure. Amongst the relative aspects most important to the total quality of any concrete it is the curing, that becomes basic when is about HPC. The curing of the high performance concrete constitutes in a controversial subject in the technician area as well as the type and duration of it, therefore the necessity of a deeper refined study on this subject. This research verifies the influence of the type and time of duration of curing in the mechanical properties of the HPC (compressive strength, flexion tensile strength and module of deformation), produced in Goiânia in hot period (t>25ºC) and of low relative humidity of air (h<50%) situation this considered critical for NBR 14931/2003 and predominant in the months of May the September in this region. In the experimental study were produced HPC of target compressive strength 60, 80 and 100MPa, from the Furnas Mix Proportion Method, using cement CP II-F-32, silica fume, polycarboxylate based superplasticizer, natural sand and crushed stones nº 0 of the granulite. 14 cures of different type and times of duration had been applied: curing with permanence of 1, 3, 7, 14, and 28 days inside of the humid chamber; curing with aspersion of water during 1, 3, 7, 14 and 28 days; chemical curing based on paraffin and chemical curing based on chloride rubber; cure for aspersion of water during 7 days and later sealing of the part with membrane of curing based on chloride rubber and air curing. For concretes of target compressive strength to the 28 days of 60 MPa and 80 MPa, the best type of curing was "saw humid" (curing in humid chamber and curing with aspersion of water) and the best time of duration humid was 7 days. For the one of 100 MPa the best type of curing also was "saw humid", however the duration time was 14 days. According to the chemical curing, some times the results had been even though less than to the one of reference (air curing). Among the two types of used chemical curing, difference in the results of compressive strength was not verified, despite the chemical membrane based on paraffin has an inferior cost to the chloride rubber base. / No caso de concreto convencional, pequenos defeitos construtivos, variações de dosagem ou mesmo curas inadequadas podem não comprometer significativamente o material. Já no CAD exige-se um rigor no controle desde sua dosagem até a execução, pois qualquer falha pode trazer sérios prejuízos ao material ou a estrutura. Dentre os aspectos mais importantes relativos à qualidade total de qualquer concreto está a cura, o que se torna fundamental quando se trata de CAD. A cura do concreto de alto desempenho constitui assunto polêmico no meio técnico assim como o tipo e duração desta, por isso a necessidade de um estudo mais apurado sobre este tema. Esta pesquisa verifica a influência do tipo e tempo de duração de cura nas propriedades mecânicas do CAD (resistência à compressão, resistência à tração na flexão e módulo de deformação), produzidos em Goiânia em período quente (t>25ºC) e de baixa umidade relativa do ar (h<50%), situação esta considerada crítica pela norma NBR 14931 (ABNT, 2003) e predominante nos meses de maio a setembro na região. No estudo experimental foram produzidos CAD de resistência à compressão estimada 60, 80 e 100MPa, a partir do Método de Dosagem de Furnas, utilizando cimento CP II-F-32, sílica ativa, superplastificante à base de éter carboxilato, areia natural e brita 0 de granulito. Foram aplicados 14 curas de diferentes tipos e tempos de duração: cura com permanência de 1, 3, 7, 14, e 28 dias dentro da câmara úmida; cura através de aspersão de água durante 1, 3, 7, 14 e 28 dias; cura química com membrana à base de parafina e à base de borracha clorada; cura através de aspersão de água durante 7 dias e depois selagem da peça com membrana de cura à base de borracha clorada e cura ao ar. Para os concretos de resistência estimada aos 28 dias de 60 MPa e de 80 MPa, o melhor tipo de cura foi via úmida (cura em câmara úmida e cura através de aspersão de água) e o melhor tempo de duração foi 7 dias. Para o de 100 MPa o melhor tipo de cura também foi via úmida , porém o tempo de duração foi 14 dias. Quanto à cura química, algumas vezes os resultados foram até mesmo inferiores ao de referência (cura ao ar). Dentre os dois tipos de curas químicas utilizados não verificouse diferença nos resultados de resistência à compressão, salientando-se que a membrana química à base de parafina tem custo inferior à base de borracha clorada.

A presente pesquisa trata da investigação experimental do comportamento de pilares por meio de encamisamento com concreto de alta resistência. Os principais objetivos da pesquisa são estudar o comportamento ao longo do tempo e o efeito de précarregamento nos pilares reforçados. Foram ensaiados vinte modelos experimentais, variando-se a forma da seção transversal (circular e quadrada), a taxa de armadura transversal da camisa de reforço e a existência ou não de pré-carregamento. Foram também realizados ensaios complementares sobre pilares curtos de seção circular para observação dos efeitos de confinamento. Ensaios de caracterização dos concretos utilizados sob ações de longa duração foram realizados. Para estudar a influência da deformação lenta, simulou-se nesta pesquisa pilares de concreto armado submetidos a pré-carregamento, os quais foram mantidos durante um certo período de tempo numa câmara climatizada. Estes pilares foram reforçados sem que fosse retirada a força de pré-carregamento.Todos os pilares foram submetidos ensaios à compressão axial de curta duração por meio de uma máquina universal de ensaios servo-hidráulica, em modo de controle de deslocamento. Na análise dos resultados foram aplicados modelos de cálculo do efeito de confinamento, análise numérica pelo Método dos Elementos Finitos e outras formulações teóricas, para efeito de confrontação de resultados teóricos e experimentais. As principais conclusões são de que, no reforço por encamisamento de pilares, uma vez garantidas adequadas condições de confinamento: a capacidade resistente do pilar original pode ser totalmente considerada na avaliação da resistência do elemento reforçado; o efeito de pré-carregamento de um pilar reforçado não afeta a resistência última do elemento reforçado, mas pode afetar a sua deformabilidade. Além disso, na análise do comportamento dos pilares ao longo do tempo, pôde-se perceber que houve transferência de esforços entre o pilar original e a camisa de reforço, mas seu efeito foi pouco significativo em termos de alteração da capacidade resistente / The thesis presents an experimental investigation on the behavior of RC columns strengthened by high-performance concrete jackets. The main objectives are to analyze the immediate and time-dependant behavior of the elements and the preloading effect in its load capacity and deformability. Twenty columns were tested varying the transversal section shape (circular and square), transversal reinforcement ratio of the jacket and the preloading condition. Also complimentary tests were made on short circular section columns to observe confinement effects. A set of long-term tests was made to characterize the concrete immediate and time-dependant properties. To analyze the influence of time-dependant deformations, original columns were submitted to preloading forces and they were kept in a weather-controlled chamber during a certain period. The high-performance concrete jackets were applied to the original columns without removing the preloading forces. Every column was subjected to a monotonic axial compression test in a servohydraulic universal machine, in the displacement-controlled mode. In the analysis of the results theoretical models of concrete confinement, Finite Element Method simulations and other formulations were applied to examine the experimental results. The main conclusions are that, if adequate confinement conditions are maintained in the strengthened columns: the load capacity of the original column can be totally considered in strength evaluation; the preloading effect does not affect the ultimate load of the rehabilitated member, but it may affect the column deformability. Moreover, in the long-term behavior analysis, load transfer between the original column and jacket was observed. However, its effect was not significant in the load capacity of the strengthened member

Most of the moveable bridges use open grid steel decks, because these are factory assembled, light-weight, and easy to install. Open grid steel decks, however, are not as skid resistant as solid decks. Costly maintenance, high noise levels, poor riding comfort and susceptibility to vibrations are among the other disadvantages of these decks. The major objective of this research was to develop alternative deck systems which weigh no more than 25 lb/ft2, have solid riding surface, are no more than 4-5 in. thick and are able to withstand prescribed loading. Three deck systems were considered in this study: ultra-high performance concrete (UHPC) deck, aluminum deck and UHPC-fiber reinforced polymer (FRP) tube deck. UHPC deck was the first alternative system developed as a part of this project. Due to its ultra high strength, this type of concrete results in thinner sections, which helps satisfy the strict self-weight limit. A comprehensive experimental and analytical evaluation of the system was carried out to establish its suitability. Both single and multi-unit specimens with one or two spans were tested for static and dynamic loading. Finite element models were developed to predict the deck behavior. The study led to the conclusion that the UHPC bridge deck is a feasible alternative to open grid steel deck. Aluminum deck was the second alternative system studied in this project. A detailed experimental and analytical evaluation of the system was carried out. The experimental work included static and dynamic loading on the deck panels and connections. Analytical work included detailed finite element modeling. Based on the in-depth experimental and analytical evaluations, it was concluded that aluminum deck was a suitable alternative to open grid steel decks and is ready for implementation. UHPC-FRP tube deck was the third system developed in this research. Prestressed hollow core decks are commonly used, but the proposed type of steel-free deck is quite novel. Preliminary experimental evaluations of two simple-span specimens, one with uniform section and the other with tapered section were carried out. The system was shown to have good promise to replace the conventional open grid decks. Additional work, however, is needed before the system is recommended for field application.

Ultra-high performance concrete (UHPC) was evaluated as a potential material for future bridge deck designs. Material characterization tests took place to identify potential challenges in mixing, placing, and curing UHPC. Biaxial testing was performed to evaluate behavior of UHPC in combined tension and compression stress states. A UHPC bridge deck was designed to perform similarly to a conventional concrete bridge deck, and a single unit bridge deck section was tested to evaluate the design methods used for untreated UHPC. Material tests identified challenges with placing UHPC. A specified compressive strength was determined for structural design using untreated UHPC, which was identified as a cost-effective alternative to steam treated UHPC. UHPC was tested in biaxial tension-compression stress states. A biaxial test method was developed for UHPC to directly apply tension and compression. The influence of both curing method and fiber orientation were evaluated. The failure envelope developed for untreated UHPC with random fiber orientation was suggested as a conservative estimate for future analysis of UHPC. Digital image correlation was also evaluated as a means to estimate surface strains of UHPC, and recommendations are provided to improve consistency in future tests using DIC methods. A preliminary bridge deck design was completed for untreated UHPC and using established material models. Prestressing steel was used as primary reinforcement in the transverse direction. Preliminary testing was used to evaluate three different placement scenarios, and results showed that fiber settling was a potential placement problem resulting in reduced tensile strength. The UHPC bridge deck was redesigned to incorporate preliminary test results, and two single unit bridge deck sections were tested to evaluate the incorporated design methods for both upside down and right-side up placement techniques. Test results showed that the applied design methods would be conservative for either placement method. / Ph. D.

When compared to traditional concrete, steel fibre reinforced concrete (SFRC) shows several enhancements in performance, including improved tensile resistance, toughness and ductility. One potential application for SFRC is in columns where the provision of steel fibres can improve performance under axial and lateral loads. The use of SFRC can also allow for partial replacement of transverse reinforcement required by modern seismic codes. To improve workability, self-consolidating concrete (SCC) can be combined with steel fibres, leading to highly workable SFRC suitable for structural applications. Recent advances in material science have also led to the development of ultra-high performance fibre reinforced concretes (UHPFRC), a material which exhibits very high compressive strength, enhanced post-cracking resistance and high damage tolerance. In heavily loaded ground-story columns, the use of UHPFRC can allow for reduced column sections. This thesis presents the results from a comprehensive research program conducted to study the axial behaviour of columns constructed with highly workable SFRC and UHPFRC. As part of the experimental program, twenty-three full-scale columns were tested under pure axial compressive loading. In the case of the SFRC columns, columns having rectangular section and constructed with SCC and steel fibres were tested, with variables including fibre content and spacing of transverse reinforcement. The results confirm that use of fibres results in improved column behaviour due to enhancements in core confinement and cover behaviour. Furthermore, the results demonstrate that the provision of steel fibres in columns can allow for partial replacement of transverse reinforcement required by modern codes. The analytical investigation indicates that confinement models proposed by other researchers for traditional RC and SFRC can predict the response of columns constructed with SCC and highly workable SFRC. In the case of the UHPFRC columns, variables included configuration and spacing of transverse reinforcement. The results demonstrate that the use of appropriate detailing in UHPFRC columns can result in suitable ductility. Furthermore, the results demonstrate the improved damage tolerance of UHPFRC when compared to traditional high-strength concrete. The analytical investigation demonstrates the need for development of confinement models specific for UHPFRC.

This research project has been undertaken to produce and characterize the behavior of High Strength Cementitious Mix (HSCM), which has considerably higher compressive strength compared to conventional concrete. Components of HSCM are cement, silica fume, sand, water, and high range water reducer. The material is tested for compressive strength and impact energy absorption capacity while the amount of above mentioned components are varied parametrically. The effect of these parameters are extensively studied and trends are reported. Finally, this research projects attempts to find correlations among compressive strength, compressive toughness, and impact toughness. Limitations of the experimental program are discussed and future direction for improvement and expansion of the research program is suggested.