High Compressive Strength Concrete Research Articles

Investigation of the Impact of Glass Waste in Reactive Powder Concrete on Attenuation Properties for Bremsstrahlung Ray

Reactive Powder Concrete (RPC) is one of the most advanced recent high compressive strength concrete. This work explored the effects of using glass waste as a fractional replacement for fine aggregate in reactive powder concrete at levels of 0%, 25%, 50%, and 100%. Linear and mass attenuation coefficients have been calculated as a function of the sample's thickness and bremsstrahlung energy. These coefficients were obtained using energy selective scintillation response to bremsstrahlung having an energy ranging from (0.1-1.1) MeV. In addition, the half-value thickness of the samples prepared has been investigated. It was found that there is a reversal association between the attenuation coefficient and the energy of the bremsstrahlung ray.
 The results showed that, with the exception of the specimen with a partial replacement of 25% glass waste, adding fine aggregate in part by glass waste had a negative impact on the reactive powder concrete's attenuation properties. That means the sample’s density can be improved with the glass waste content ratio to 25%. Also, the bremsstrahlung radiation shielding capabilities of reactive powder concrete can be enhanced using glass waste of not more than 25%.

Planning For The Construction of Cikeas River Bridge Wiht-Prestressed Beam Structure Method. of Housing Crv Residence Case Study

Along with the development of the times and technological advances, present a concept that is slightly different from the concept of ordinary reinforced concrete. The combination or active combination of high compressive strength concrete and steel with high tensile strength or prestressed cables produces a concept called Prestressed Concrete. Prestressed concrete is basically concrete in which the internal stresses of a suitable magnitude and distribution are given in such a way that the stresses caused by the external loads are resisted to a desired level. In reinforced concrete bars, prestress is generally provided by pulling the reinforcing steel. In this study, I as a researcher will plan the construction of the Cikeas River Bridge with the Strategic Prestressed Beam Structure Method. Case Study of CRV RESIDENCE Housing, located on Jalan Parpostel Raya, Jatiluhur Village, Jati Asih District, with a land area of 7.5 hectares. On the south side the housing is located in Jatiasih Village area with a land area of 2.3 hectares, and the remaining 5.2 hectares is located in Bojong Kulur Village, Bogor Regency. The two housing sites are separated by the Cikeas River flow. Based on the condition of the housing area which is divided into two, to connect the two areas a connecting bridge development plan is made. In the construction of this bridge it is planned to use strategic concrete which is installed on the bridge girder beam. Since this bridge has a long stretch with a width of 9 meters and a length of 23 meters, the bridge is planned with three supports each with a pedestal distance of 11.50 meters. The reasons and objectives of the writing of the final project Assess the load planning on the bridge structure, study the strategic beam profile planning, and study the planning of Tendon requirements and the location of the Tendon position on the strategic beam The method used in calculating the PCI Girder type prestressed concrete and the Post-tensioning system is based on the design and Calculation of prestressed girder beams (Precast) using the Post-tensioning method is obtained with a beam profile with a height of H = 90 cm and a width of 70 cm with a girder span of 11.50 meters consisting of 2 VSL Ø ½ inch tendons, Uncoated type 7 wire super strands ASTM A- 416 grade 270 with 27 strands and using main reinforcement Ø 13 mm, shear Ø 12 mm, and shear connector Ø 12 mm.

Experimental investigation on the stress-strain behavior of unsaturated polyester polymer concrete subjected to monotonic and cyclic loadings

The use of polymer concrete (PC) in construction requires the development of an accurate stress-strain relationship that can accurately predict the mechanical properties of PC. Given that no constitutive equation for cyclic loading of unsaturated polyester PC (UPPC) is available in the literature, the goal of the current research has been to propose a rational analytical model for estimating the mechanical characteristics of UPPC under tensile and compressive loading. Compressive and tensile cyclic and monotonic tests were performed on specimens which had been cured for 28 days and the average monotonic stress-strain curve was obtained for the monotonic tests. The average maximum stress and strain were determined for both the compressive and tensile tests and the elastic modulus and energy absorption capacity were computed and compared with the values for normal concrete (NC) and high strength concrete (HSC) materials. Analytical models for the monotonic and skeleton curves for both tensile and compressive tests have been provided, and the proposed models were compared to experimental findings and other research results for validation. Stress-strain relationships have been proposed for the unloading and reloading paths and were compared with the cyclic test results. The ultimate stress and strain for the UPPC were three and five times higher, respectively, than for the NC in tension testing. The ultimate strain for UPPC was almost 150% greater than the final strain of HSC in compression. Under compressive loading, the UPPC absorbed to 2.33 and 5.3 times more energy, respectively, than the HSC and NC. The results showed that the skeleton curves agreed well with the monotonic curves for the compressive and tensile tests. All of the proposed models agreed well with the available experimental data and previous study results.

Behavior of precast hollow slabs with different ratios of shear span to effective depth

This study presents an experimental work to examine the effect of shear span to effective depth (a/d) ratio on the behavior of precast hollow slab. For this purpose, tests were performed under the effect of four lines loading of different shear span values to effective depth (a/d) ratios (1.5, 2, 3.5 and 5). This test program involved four full-scale precast prestressed hollow core slabs, with width of 1200 mm, length of 2000 mm, and thickness of 160 mm. The entire set of hollow-core slabs was cast using a high compressive strength concrete of about 79.5 MPa at the age of 28 days. Based on the experimental results, the four failure mode patterns were highly dependent on the (a/d) ratio. These modes include, shear compression failure, flexural failure, and flexure-shear failure. While the fourth failure mode was represented as a combination of anchorage failure and tension shear, this failure pattern was accompanied by slippage of strand reinforcement in concrete. It has been found that a decrement percentage of 19.58% was recorded for different failure loads, whereas the percentage of (a/d) ratio was increased by 233.3%. In addition, the highest first crack load of 110 kN was obtained by sample HCS 1.5 that had the lower (a/d) ratio.

Irradiation Duration Effect of Gamma Ray on the Compressive Strength of Reactive Powder Concrete

Reactive Powder Concrete (RPC) could be considered as the furthermost significant modern high compressive strength concrete. In this study, an experimental investigation on the impact of micro steel fiber volume fraction ratio and gamma ray irradiation duration influence upon the compressive strength of RPC is presented. Three volume fraction ratios (0.0, 1.0 and 1.5) % was implemented. For each percentage of the adopted fiber ratios, six different irradiation duration was considered; these are (1, 2, 3, 4, 5 and 6) days. Gamma source (Cs-137) of energy (0.662) MeV and activity (6) mci was used. In a case of zero volume fraction ratio, the experimental results showed that gamma ray had a significant influence on the reducing of the compressive strength varies between (1.2-8.6)% for a period of (1-6) days, respectively. Although there was a decrease in the compressive strength for a state of non-zero volume fraction ratio (1 and 1.5) % varies between (1.0-3.1 and 0.4-1.6) %, respectively, the attained results indicated that gamma ray had no significant effect to reduce the compressive strength of the RPC that’s included micro steel fibers as a volume fraction.

Derivation of Complete Stress–Strain Curve for SSTT-Confined High-Strength Concrete in Compression

Abstract For concrete structural behavior analysis, the complete axial stress–strain curves in compression can be determined by using a closed-loop servo-controlled hydraulic testing machine. The applied loading as well as the axial deformation reading of the loaded concrete specimen is recorded from the built-in displacement transducers or externally installed transducers placed between the machine platens. However, the recorded axial strain in the ascending branch is not purely concrete deformations but includes some additional deformation because of machine flexibility and specimen’s end restraint. Strain gauges can be diametrically installed at the middle of specimen for a more precise deformation reading but additional costs are required for the gauges and data acquisition system. Moreover, the concrete stress–strain curve and ductility performance beyond its ultimate is difficult to be recorded without special strain measuring devices. Hence, a correction equation is needed to account for these effects to obtain the complete stress–strain curves for unconfined and confined concrete. In this paper, a total number of 84 unconfined and steel strapping tensioning techniques (SSTTs) confined high-strength concrete cylinders of compressive strength ranging from 62.48 MPa to 184.85 MPa were tested in compression in accordance with ASTM C39/C39M-11. The details for the testing setup, testing machine, strain measuring instruments, loading rate, loading patterns, etc. are described and at the same time a correction factor equation is proposed in this paper.

Prestressed Precast Hollow-Core Slabs with Different Shear Span to Effective Depth Ratio

Four full scale precast prestressed hollow-core slabs were tested under the influence of four lines loading with various values of shear span to effective depth ratio (a/d) (1.5, 2, 3.5 and 5). The dimensions of the hollow-core slab were 2000 mm, 1200 mm and 150 mm (length, width and thickness, respectively). All slabs were cast with a high compressive strength concrete of approximately 79.5 MPa. Experimental test results showed four patterns of failure mode depending on the ratio of (a/d). They were flexural failure, flexure-shear failure and shear compression failure. In addition to combination failure between tension shear and anchorage failure, accompanied by sliding strand in concrete. The failure loads decreased about 19.6% as (a/d) increased by 233.3%. Finally, the highest first crack load, 110kN, was recorded for sample, HCS 1.5, having the lowest (a/d) ratio.

Experimental Investigation on Self-Compacting Self-Curing Concrete Incorporated with the Light Weight Aggregates

ABSTRACT Self-Compacting Concrete (SCC) flows around obstructions by its self-weight to fill entirely and self-consolidate (without any need for vibration), without any part of disconnection and chunking. The eradication of the need for consolidation leads to better quality concrete and substantial improvement of running conditions. The fresh state of SCC mixes will usually have huge amount of fine fillers, including cement, and produce excessively high compressive strength concrete. In order to overcome the workability problem Super Plasticizer (SP) and Viscosity Modifying Agent (VMA) are used. Here, the workability admixtures are fixed at a constant rate of 2% based on the weight of cement. This technique examines special applications in cases of bottleneck reinforced sections, rafts, tunnel linings, highly reinforced columns, underwater repairs, bridge piers and placements. LECA and Vermiculite have high porosity, and are added to concrete mixtures to create a lightweight concrete mix. An attempt has been made to develop a combination of self-compacting and self-curing concrete with each 5% and 10% of LECA and Vermiculite as a partial replacement to fine aggregate. As there was no proper mix design for the development of this modern concrete, the design has been carried out based on EFNARC specifications for the design strength of M40 grade concrete. The porosity of light weight aggregate provide source of water for internal curing of concrete which enhances concrete strength and durability. Based on more trials, it was noticed that the concrete with 10% of LECA and Vermiculite in individual provides good results.

Medium strength self-compacting concrete containing fly ash: Modelling using factorial experimental plans

Fresh self-compacting concrete (SCC) flows into place and around obstructions under its own weight to fill the formwork completely and self-compact, without any segregation and blocking. The elimination of the need for compaction leads to better quality concrete and substantial improvement of working conditions. SCC mixes generally have a much higher content of fine fillers, including cement, and produce excessively high compressive strength concrete, which narrows its field of application to special concrete only. To obtain maximum benefit from SCC, it has to be adopted in general concrete construction practice. Such practice requires inexpensive and medium strength concrete. This investigation aims to develop medium strength SCC (MS-SCC). The cost of materials will be decreased by reducing the cement content and by using pulverised fuel ash (PFA) with a minimum amount of superplasticizer (SP). A factorial design was carried out to mathematically model the influence of five key parameters on filling and passing abilities, segregation and compressive strength, which are important for the successful development of medium strength self-compacting concrete incorporating PFA. The parameters considered in the study were the contents of cement and PFA, water-to-powder (cement+PFA) ratio (W/P) and dosage of SP. The responses of the derived statistical models are slump flow, fluidity loss, Orimet time, V-funnel time, L-box, JRing combined to the Orimet, JRing combined to cone, rheological parameters, segregation and compressive strength at 7, 28 and 90 days. Twenty-one mixes were prepared to derive the statistical models, and five were used for the verification and the accuracy of the developed models. The models are valid for mixes made with 0.38 to 0.72 W/P, 60 to 216 kg/m 3 of cement content, 183 to 317 kg/m 3 of PFA and 0% to 1% of SP, by mass of powder. The influences of W/P, cement and PFA contents, and the dosage of SP were characterised and analysed using polynomial regression, which can identify the primary factors and their interactions on the measured properties. The results show tha MS-SCC can be achieved with a 28-day compressive strength of 30 to 35 MPa by using up to 210 kg/m 3 of PFA.

The use of advanced polymer composites to form an economic structural unit

An advanced polymer/continuous fibre composite (APC) and concrete system is an example in which two very dissimilar materials can be joined to form a composite structure. In the current investigation a duplex beam will be analysed where the high-compressive strength concrete is placed above, and the high strength and stiffness fibre/polymer composite is placed below the neutral axis; in this form the two materials will be used to their best advantage. When this structural duplex Tee beam is under load, two failure criteria of the system have been identified. These are the failure of the shear bond between the APC permanent shuttering and the concrete, and failure by buckling of the composite web of the beam. The experimental test results show that the shear bond is not critical. Buckling occurs in the specified panels at 20% of the ultimate load. On increasing the load, the beam continues to perform conventionally and fails in the concrete by crushing. In addition, the paper shows that the performance of the APCs are not impaired by long-term creep and fatigue loading whilst the concrete element shows a typical reduction in stiffness for these types of loading regimes.

Statistics of High-Strength Concrete Cylinders

The results of a statistical analysis on steam-cured, plant-produced high-strength concrete in compression based on about 2,200 cylinders obtained from several concrete producers in the United States is summarized. The statistical analysis considers the actual-to-specified concrete strength ratio, coefficient of variation, and probability distribution function. The seasonal effect on the statistical properties of the strength is also included. The results of the analysis showed that both the mean-to-nominal and the coefficient of variation are higher for normal strength concrete than for high-strength concrete. The mean-to-nominal ratio varies between 1.078 and 1.255, whereas the coefficient of variation is in the range of 0.06528-0.1353, depending on the specified 28-day concrete strength. Also, the analysis showed that the mean-to-nominal ratio and the coefficient of variation for concrete produced in the cold season are both lower than the corresponding statistics for concrete produced in the warm season. The study will help code developers in generating probabilistic resistance models for concrete structures that can be used in the development of load resistance factor design codes.

Stress-Strain Relationship of High-Strength Concrete in Compression

An experimental investigation was carried out to generate the complete stress-strain curves of concrete in compression with a strength range of 50–120 MPa. The variation in concrete strength was achieved by varying the water-to-binder ratio of the mix, types of cement replacing admixture, replacement percentages, and the age at testing. The effects of these parameters on the shape of stress-strain curves are presented and discussed. The accuracy of predictions of a number of analytical models available in the literature are also discussed. Based on present test data, a simple model is proposed to generate the complete stress-strain relationships for high-strength concrete. The proposed model has been found to give a good representation of the actual stress-strain response.

Statistical Properties of Plant-Produced High Strength Concrete in Compression

The determination of resistance reduction factors to account for material variability in the development of Load and Resistance Factor Design (LRFD) codes depends on the statistics of the materials involved. This paper summarizes the results of a statistical analysis on steam-cured plant-produced high strength concrete in compression based on 399 specimens obtained from concrete producers in Pennsylvania. The seasonal effect on the mean-to-nominal ratio, coefficient of variation, and probability distribution shape is also considered. Statistics on cylinder strengths are used to predict the variability of in-situ concrete. The results of the analysis show that high strength concrete has superior statistical properties compared to conventional concrete due to better quality control measures. The study will help code developers and engineers in the generation of probabilistic resistance models for structures made with high strength concrete.

A la recherche d'un béton de 150 MPa

It is possible to make in 1983 a field concrete in the Montreal area having a 28-day compressive strength of 120 MPa, using locally available materials.To obtain such a high compressive-strength concrete, it has been necessary to study the overall performances of 8 different cements, 3 types of sand, 16 types of aggregates, 3 types of superplasticizers, 9 grain-size distributions of the coarse aggregate, and 5 different ways of batching. An ultra high strength concrete is not obtained by chance, but through a long research effort planned in a laboratory as well as in the field.Such a concrete is feasible using: (1) high cement dosage of type 10, 20, or 30, according to the desired rate of compressive strength development; (2) a cubical coarse aggregate having a high compressive strength and an elastic modulus as near as possible as that of the mortar; (3) a manufactured sand having a high fineness modulus made from the same rock as the coarse aggregate; (4) a very high dosage of superplasticizer; and (5) 5 to 8% of condensed silica fume. The limited efficiency of the present industrial mixers (tilt mixers) for the very special mixes of this study is actually the main limitation for reaching a strength of 150 MPa. Keywords: high compressive strength concrete, superplasticizer, condensed silica fumes, manufactured sand, grain-sizes, aggregates, retarder, ready-mix concrete, precast plants.