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Steel-fibre reinforced polymer (FRP) composite bar (SFCB) is a novel form of rebar. The main technique for SFCB manufacturing, which is described briefly in this paper, is a manual technique, and this study cast eight slabs using this procedure to investigate the flexural behavior of SFCB-reinforced concrete slabs by comparing them with concrete slabs reinforced with ordinary steel bars. The study included an investigation of changes in the thickness of slab, the effects of the CFRP sheet length wrapped around the steel bars, and concrete compressive strengths. The outcomes showed that, increasing the slab thickness from 80 to 100 mm led to an increase in the ultimate load capacity of 55%, while utilising SFCB reinforcement enhanced the ultimate load capacity, with maximum percentage increases ranging from 23% to 41%. Furthermore, the results showed that replacing NC with RPC offered slight enhancements in the ultimate load: this was about 12% in the control slab, while when SFCB was used, the improvement was 16%. Finally, a length of reinforcement two-thirds of the full length of the bar was found to be the optimum length when used for strengthening. Within this paper, the methodology and results are first outlined, then a brief conclusion offered with regard to the investigation overall. [ABSTRACT FROM AUTHOR]

Waste rubber tires have been used in building materials to support the environment and green construction. There is a growing demand for rubberized materials as they are cost-effective and useful from a sustainable standpoint. There are several properties of the rubber tire that could be applied usefully such as low density, and waterproofing properties. Rubberized concrete has composed of waste rubber as natural aggregate and is an alternative solution to the use of tire rubber particles in the production of concrete. It has been proven that the addition of waste rubber tires to concrete starts to low strength and this restriction its application in structural elements but benefits to enhance the ductility, impact resistance, thermal conductivity, and acoustic properties. This paper presents a review of the recent studies on the application and development of artificial neural networks (ANNs) to predict the compressive strength of rubberized concrete. From this review, predicting the compressive strength of rubberized concrete by ANNs is generally more accurate, and their development is inexpensive and time-saving. In this review, the advantages, and limitations of ANNs to predict the compressive strength of rubberized concrete, as well as some new research trends have been addressed. [ABSTRACT FROM AUTHOR]

This paper aims to determine the workability and compressive strength of geopolymer using silica sand as a fine aggregate. Eight different mixtures were mixed with different ratios of geopolymer paste-to-silica sand and different percentages of superplasticizer. The water-to-so ratio was kept constant at 0.35. The ratio of Na2SiO3/NaOH is constant at 2 with 10 Molarity of NaOH. The percentages of superplasticizer varied from 1%, 1.5%, and 2%. The results show that the less silica content in the geopolymer mortar results in higher workability. The flow table test result in this research (180-250 mm) can be classified as high-workability geopolymer mortar. Adding superplasticizer in the range of 1-2% from fly ash does not affect the workability and the compressive strength of geopolymer mortar. The highest compressive strength of geopolymer mortar is more than 40 MPa at sample S2 with 1% superplasticizer. [ABSTRACT FROM AUTHOR]

Melaleuca Cajaputi (Kayu Galam) is a type of tree that grows very fertile in swampy areas. This wood is commonly used in natural conditions (barked) in construction work. Meanwhile, other woods are generally used in a processed condition (without bark). For this reason, this paper compared galam wood with bark and without bark. This research was conducted by testing the physical characteristics and compressive strength in the laboratory. The compressive strength samples consisted of natural conditions (irregular round shape) with variations in length of 10 cm, 15 cm and 30 cm. Furthermore, each variation is made into a barked and peeled bark. All samples amounted to 126 units. The results of specific gravity and water content were not significantly different between barked and without bark. The water absorption in the shelled galam was 49.25% greater than that without the bark. Furthermore, the effect of the galam bark layer reduces the average strength by 24.92% and undergoes compression and shear failure. The failure of the test object with a ratio of length to diameter greater than 5 is indicated to have a buckling effect. [ABSTRACT FROM AUTHOR]

This paper deals with the thermal activation of brick clays. The main aim was to assess the possibility of their activation and afterwards also the applicability of such clays as supplementary cementitious materials. Three different brick clays were examined, varied in origin localities, and mainly in chemical and mineralogical composition. Their thermal activation was done at two different temperatures, namely exposure to 550 °C and 600 °C were investigated. The impact of temperatures was found to be of great importance. Clays exposed to 600 °C showed extremely higher specific surface area, and somewhat lower bulk density compared to those treated at 500 °C. Afterwards, blended cement pastes containing 10% of particular thermal activated clays were produced, and at the age of 28 days bulk density, bending strength and compressive strength were measured. The impact of temperature was indisputable. The exposure to 600 °C led to the blended cement pastes which showed better performance than the one treated at the lower temperature. However, the studied properties showed suitable values, and thus this study confirmed, that the thermal activation of brick clays is possible. [ABSTRACT FROM AUTHOR]

Beams of reinforced concrete with flanges have been utilized extensively in a lot of applications in structural engineering. The total behavior of this type of member has been studied experimentally and analytically. In this paper, a finite element method-based numerical analysis was used to presented the reinforced concrete's behavior with flanges during the pre-and post-cracking level of loading up to their ultimate stress. Different types of flanged reinforced concrete beams were analyzed, and the results from finite element (F.E.M) were compared with experimental and analytical data. The impact of concrete's compressive strength has been examined. In general, excellent agreement has been obtained between the results of finite element and experimental tests. Also studied numerically is the distribution of concrete longitudinal compressive stresses and tensile stresses along the steel reinforcement. It is found that for high-strength concrete, the ACI Code 318M-14 underestimates the collapse moment of flanged reinforced concrete beams. [ABSTRACT FROM AUTHOR]

Amazing advances in concrete technology and the accessibility of a wide range of materials such as high-range water-reducing admixtures and silica fume have been made these days. It can be said there is high probability to obtain the production of ultra high performance fiber reinforced concrete (UHPFRC) that can provide compressive strength up from 120 MPa to 185 MPa. Because of its remarkable improvement in durability, UHPFRC usage in concrete columns have increased lots of interest in the strengthening and retrofitting of concrete structures. The aim of this study is to investigate the effect of cross-sectional shape properties of fire damaged concrete on the confinement of UHPFRC in which the key parameters relative to its performance are cross sectional area, aspect ratio, and side to corner radius ratio (B/r) of concrete. This study proposes to use UHPFRC as jacketing material for fire damaged concrete columns. However, its application for fire damaged concrete columns is very limited. Numerical study by Leonardi et al. (2010) found that UHPFRC has very promising potential for jacketing material for fire damaged square concrete columns, but experimental study is required for verification. Thereafter, thorough investigations were carried out in this paper in order to explore the confinement efficacy of UHPFRC jackets using various parameters as mentioned. In which, the investigated cross-sectional shape properties of concrete are critical factors in determining the successfulness of repair material used in rehabilitant of fire damaged reinforced concrete. Therefore, the results from this research can be used by engineers to predict the improvement made by UHPFRC confinement on fire damaged. It is believed that this research able to increase the human capital with the knowledge and expertise in strengthening work for fire damaged concrete structures. [ABSTRACT FROM AUTHOR]

Most of the studies have done on fiber reinforced polymer (FRP) wrapped RCC columns are on the columns having circular cross section. But on the site most of the RCC columns are of rectangular or square cross section. This paper presents experimental strength evaluation of RCC square column wrapped with and without carbon fiber reinforced polymer wrapping. This study presents the insight into comparison of compressive strength of RCC square column which are without CFRP wrapped, centrally CFRP wrapped and three sided CFRP wrapped columns which are cast using M15 and M20 grade of concrete. The effect of wrapping of carbon fiber reinforced polymer with different conditions was studied by testing 18 RCC columns. The specimens are of dimension 150mm x 150mm x 1524 mm and having square cross section. [ABSTRACT FROM AUTHOR]

Magnesium-Carbonate Apatite (Mg-CA) is an alternative biodegradable magnesium metal-based material that has the potential to be developed for temporary bone implants. As reinforcement, CA bioceramic is interesting to use because it has a composition like bone and has better osteoconductivity than hydroxyapatite (HA), so it is expected that it will help heal traumatized bones more quickly. Besides that, the CA used is a local product. This research on the development of Mg-xCA is a series of studies being carried out, one of which aims to improve its mechanical properties. Previous studies have shown that efforts to improve the mechanical properties of powder-based Mg-xCA using a sintering process are considered less effective, so other methods are needed. This paper contains further efforts to improve the mechanical properties of Mg-xCA, especially Mg-10CA resulting from initial compaction by warm compaction process. The method used is a deformation strengthening process through a hot extrusion process with an extrusion ratio (R) of 1.44. Characterizations were carried out including hardness, compressive strength, and microstructure. As a comparison, the characteristics of the previous sinter research results were used. The results showed that the compressive strength of extruded Mg-10CA (R1.4) increased 44.3% compared to the initial compaction condition with warm compaction (WC) or 68.3% greater than the further compaction with conventional sintering (CS). [ABSTRACT FROM AUTHOR]

The findings of a study on concrete mix design using calcined clay pozzolona from (Lasjan) Pampore in Jammu and Kashmir (India) as a partial replacement for cement in structural applications are presented in this paper. Many scientific studies have looked into the impact of calcined clay on the strength qualities of typical Portland cement concrete. In our work, a part of cement is being replaced by calcined clay with 0 to 30% to form binder pastes and concrete. The M25grade concrete was prepared and compressive strength was investigated against the plain concrete. The various other testslike setting time tests and normal consistency tests were also implemented for blended concrete and compared with plain concrete. Concrete with calcined clay pozzolona as a partial replacement for cement had a long time to set. It also shows a drop in compressive strength growth at early periods like 7 and 28 days. However, when compared to plain concrete, the compressive strength increases dramatically after 28 days. This study recommends up to 20% replacement of cement in M25 grade concrete by calcined clay, for effective results in compressive strength. [ABSTRACT FROM AUTHOR]

The soil under any foundation should be capable enough to support the transmitted loads so that the structure– foundation–soil system is stable and safe against any settlement. Any change in the unconfined compressive strength is one of the principal causes of settlement. In this paper, an approach to forecast the unconfined compressive strength of gypseous soils based on basic soil properties was developed using the Artificial Neural Networks technique. An equation was developed to estimate the unconfined compressive strength using a backpropagation algorithm to train multi-layer perceptron, in which good agreements were achieved. The model inputs were; the depth, gypsum content, liquid limit, plastic limit, plasticity index, passing sieve #200, dry unit weight, water content and initial voids ratio. The output was the forecasted unconfined compressive strength. A parametric study was conducted to investigate the generalization and robustness of the model. The findings indicated that the model was reliable within the range of utilized data. The sensitivity analysis of the model revealed that the water content had the highest relative effect, followed by passing sieve #200, dry unit weight, liquid limit, plastic limit and gypsum content, while depth, initial voids ratio and plasticity index have lower relative effects. [ABSTRACT FROM AUTHOR]

In the present paper includes an experimental investigation to study the effect of steel fiber ratio (1 to 2%) on the flexural behavior of tubular continuous Ultra High-Performance Concrete beams and the effectiveness of longitudinal reinforcement bars on the flexural behavior of UHPC continuous beams. Therefore, eight continuous tubular beams consisting of two-span were tested under one-point loading for each span. In each group, two groups were constructed, four beams, three beams are tubular, and the fourth was solid to comparison. All beams had the matching overall length of 3000 mm, the clear span distance equal to 1400 mm for each span, the same height of 200 mm, and the same width of 150 mm. The results exhibit clear improvement in the first cracking load when increasing the steel fiber ratio from 1 to 1.5% and 2% at about 11.1 and 66.6% and increasing the ultimate load at about 5.2 and 18.4%. Then when compared MXB-5 (1.5% steel fiber) with reference solid (RE.S, 1.5% steel fiber), the increase in ultimate failure load was 20%, in addition to increasing compressive strength. The ultimate load was increased at about (2.6, 15.78, and 20.1%) as the positive reinforcement ratio increased from 1% to 1.12%, 1.71%, and 1% solid beam, and the optimal ratio of steel fiber was 2%. [ABSTRACT FROM AUTHOR]