concrete materials
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Abstract Floating houses can be utilized in coastal areas as they are equipped with platforms made from expanded polystyrene system (styrofoam) and lightweight concrete covers. A lightweight concrete cover on a floating house platform made from styrofoam can improve the feasibility of housing in terms of strength, comfort and cleanliness. This research aims to obtain mixture that meet the weight and compressive strength requirements of lightweight concrete and produce them as covers on floating houses platform. The compositions of lightweight concrete materials in this research use volume ratios of 1 Pc: 2 Sand: 3 Styrofoam, 1 Pc: 1.5 Sand: 2.5 Styrofoam and 1 Pc: 1.25 Sand: 2.75 Styrofoam. The research results show that the concrete made with styrofoam qualifies as lightweight concrete with average volume weight of concrete produced between 1000-1300 kg/m3. The lightest concrete weight (1097.88 kg/m3) could be obtained from variations of mixture of 1 Pc: 1.25 Sand: 2.75 Styrofoam, The highest concrete compressive strength results were obtained from the mixture of 1 Pc: 2 Sand: 3 Styrofoam (119.26 kg/cm2). The variations of concrete mixture of 1 Pc: 2 Sand: 3 Styrofoam can be considered as lightweight concrete (≤ 1900 kg/m3).

In this paper, a parallel homogenization model for recycled concrete was proposed. A new type of finite element method, the base force element method, based on the complementary energy principle and the parallel homogenization model, is used to conduct meso-level damage research on recycled concrete. The stress–strain softening curve and failure mechanism of the recycled concrete under uniaxial compression load are analyzed using the nonlinear damage analysis program of the base force element method based on the parallel homogenization model. The tensile strength and destructive mechanisms of recycled concrete materials are studied using this parallel homogenization model. The calculation results are compared with the results of the experiments and meso-level random aggregate model analysis methods. The research results show that this parallel homogenization analysis method can be used to analyze the nonlinear damage analysis of recycled concrete materials. The tensile strength, stress–strain softening curve, and crack propagation process of recycled concrete materials can be obtained using the present method.

Infrastructure development is one of the important aspects of the progress of a country where most of the constituents of infrastructure are concrete. The most important constituent of concrete is cement because its function is to bind other concrete materials so that it can form a hard mass. The large number of developments using cement as a building material will leave quite a lot of cement bags.In this study, the authors conducted research on the effect of adding cement waste to the compressive strength of concrete. This study used an experimental method with a total of 24 test objects. The test object is in the form of a concrete cylinder with a diameter of 15 cm and a height of 30 cm and uses variations in the composition of the addition of cement waste cement as a substitute for fine aggregate, namely 0%, 2%, 4% and 6%. K200). The compressive strength test was carried out at the age of 7 days and 28 days.The test results show that the use of waste as a partial substitute for fine aggregate results in a decrease in the compressive strength of each mixture. at the age of 7 days the variation of 2% is 16.84 MPa, 4% is 11.32 MPa and for a mixture of 6% is 6.68 MPa. Meanwhile, the compressive strength test value of 28 days old concrete in each mixture decreased by ± 6 MPa. So the conclusion is cement cement waste cannot be used as a substitute for fine aggregate in fc 16.6 (K200) quality concrete because the value is lower than the specified minimum of 16.6 MPa.

Abstract The characteristics of asphalt concrete materials (ACM) composing the surfacing layer of a bituminous pavement must fulfil a requirement to maintain a level of operational capability demanded by national standards of a given country. ACM’s are a subject to significant stress caused by traffic load and climate conditions, this leads to changes in their physico-mechanical properties. The loss of physico-mechanical properties causes deterioration of road surface characteristics. Since these changes occur throughout the ACM’s life cycle, it is necessary to know the deterioration curves related to loading and time in mathematical terms, i.e. functions describing the initiation and progression of pavement’s defect in time. Pavement Performance Models (PPM) ascertained by non-destructive testing are used to objectively express the surface properties of pavements and their deterioration. The methodology consists of an analytical method to ascertain physico-mechanical characteristics of ACM’s and the use of experimental accelerated pavement testing (APT) facilities.

Concrete is a material with the ability to withstand a fairly high pressure, yet it has a low ability to withstand tension. To be utilized as a structure material, improvements need to be made to increase its tensile strength. Addition of fiber in the concrete mixture is recognized to be one among the existing methods to increase the tensile strength. Considering its high tensile strength, This study aimed to examine the compressive strength, the split tensile strength, the flexural and elastic modulus of the normal concrete with Menjalin fibers. The examination was conducted using a cylinder with the diameter of 15 cm and the height of 30 cm and a beam with the size of 15x15x60 cm. Fiber addition was 0.65% of the total concrete materials with various fiber lengths ranging from 2.5 cm, 5 cm, 7.5 cm to 10 cm. The experiment was made by the means of a concrete cylinder compressive test and a flexural test of unreinforced concrete blocks. Results of the study showed, at the age of 21 days, the highest average compressive strength value of 194.37 kg/cm2 and the split tensile strength of 30.43 kg/cm2 in the concrete with fiber of 5 cm long were obtained. The highest flexural modulus value of concrete occurred in the specimen with the fiber length of 7.5 cm (55.7 kg/cm2), while the highest elasticity of concrete occurred in the specimen with the fiber length of 5 cm (2.45x105 kg/cm2).

It is well-known that concrete is the most widely utilised construction material in the world [...]

Abstract Riparian vegetation along urban streams and wetlands is frequently dominated by invasive weeds. Elevated nitrogen and phosphorous in urban waters and soils are well-known to encourage invasive urban weeds, but this research demonstrates that other urban geochemical contaminants may also be influential. Previous studies have demonstrated that the dissolution of urban concrete is a poorly recognised source of modified water and soil geochemistry, which may enhance the growth of some invasive weeds. This study investigated the relationship between urban water quality and the growth of an invasive urban riparian weed, willow (Salix spp.) to examine the contribution of concrete materials. The study used water from a wetland in the Greater Blue Mountains World Heritage Area. These wetlands have a unique biodiversity but are fragile and susceptible to degradation from human activity. Many are in urban catchments and are frequently dominated by invasive weeds, including Salix spp. In this study, willow cuttings were grown in a laboratory using four water treatments: pristine, urban, and pristine water exposed to two different concrete materials. The urban and concrete water treatments had higher pH, salinity, calcium, potassium, and higher concentration of several metals and were associated with increased growth of Salix spp. We suggest that the modification of urban water and riparian soil chemistry by urban concrete materials may contribute to the success of invasive species in urban wetlands and riparian zones. Some metals (barium, strontium) were present in urban water and in pristine water exposed to concrete and bioaccumulated in plant tissue.