Compressive Strength Variability in High Performance Concrete with Steel Fiber Addition

In this study, an evaluation was conducted on the influence of specimen geometry on high performance concrete (HPC) with steel fiber addition with a view of monitoring the variability that exists. Strict mix design protocols were carried out in the production of the HPC based on the relevant standard, and strict procedures were ensured in the casting, consolidation, and curing of the specimens to produce viable specimens for testing. Standard 150 x 300 mm cylinder and 150 mm side cubes were utilized. There is an observed strength increase for both type of specimens and aspect ratios, as well as a noticeable wall effect especially in the cylindrical specimens at higher aspect ratio of fiber. Variability of the results is more prominent in lower aspect ratio of the fiber irrespective of the specimen type due to data range. At the end, due to strict quality control, the range of the data has been successfully reduced to about 2-3 MPa in most cases

Statistical Evaluation of Compressive Strength in High Performance Concrete (HPC) with Steel Fiber Addition

In this study, statistical analysis of High performance concrete (HPC) with steel fiber addition at 0.50, 0.75, 1.00, 1.25, & 1.50 % was evaluated each with a sample size (N) of 50 using 100 mm side cubes. Normality test and screening was done on the data set, frequency histogram with superimposed normal distribution curve plotted, as well as P-value compared with the significance level. Other parameters investigated were confidence interval and probability plot. It was seen that the data does not follow the normal distribution because the data float around the ideal normal curve, P-value is less than the significance level and Anderson-darling is high. An attempt was made to transform the data set for Goodness of fit using Johnson Transformation, and it was seen that the P-value significantly improved. Overall, an improvement in the mean compressive strength is observed with increase in fiber addition by utilizing large sample size

Properties of Concrete using Tanjung Bin Power Plant Coal Bottom Ash and Fly Ash

Coal combustion by-products (CCPs) have been around since man understood that burning coal generates electricity, and its utilization in concrete production for nearly a century. The concept of sustainable development only reawaken our consciousness to the huge amount of CCPs around us and the need for proper reutilization than the current method of disposal which has  severe consequences both to man and the environment. This paper presents the result of utilization of waste from thermal power plants to improve some engineering properties of concrete. Coal bottom ash (CBA) and fly ash were utilized in partial replacement for fine aggregates and cement respectively. The results of compressive strength at 7, 28, 56 & 90 days curing are presented because of the pozzolanic reaction. Other properties investigated include physical properties, fresh concrete properties and density. The results showed that for a grade 35 concrete with a combination of CBA and fly ash can produce 28 day strength above 30 MPa

Potential Use of Malaysian Thermal Power Plants Coal Bottom Ash in Construction

As Malaysia focuses its attention to the call for a “greener” culture, so did the engineers and those in the scientific community especially the construction industry who is a major contributor to the depletion of green house gases. The engineering and construction community has now taken up the challenge for the use of “green and recycled by-products” in construction. One of those by-products is the Coal Bottom Ash (CBA) from thermal power plants that faces an increasing production running into hundreds of thousand tonnes in Malaysia alone, and its method of disposal is relegated to landfills alone with no other commercial usage. The construction industry is now forced to rethink on the utilization of the industrial by-products as supplementary materials due to the continuous depletion of natural aggregates in construction. A significant amount of research has been conducted elsewhere on CBA to ascertain its pozzolanic activity, compressive strength in concrete and mortar, durability, water absorption characteristics and density, in order to ensure its usage as a construction material. In this paper, a critical review of the strength characteristics of concrete and mortar as influenced by CBA as partial replacement of fine aggregate is presented based on the available information in the published literatures. Diverse physical and chemical properties of CBA from different power plants in Malaysia are also presented. The influence of different types, amounts and sources of CBA on the strength and bulk density of concrete is discussed. The setting time, workability and consistency as well as the advantages and disadvantages of using CBA in construction materials are also highlighted. An effective utilization of CBA in construction materials will significantly reduce the accumulation of the by-products in landfills and thus reduce environmental pollution

Prediction of Compressive Strength in High Strength Concrete with Steel Fiber Addition using Support Vector Machine Algorithm

In this study, a support vector machine model available in Weka Algorithms, was utilized to test the predictive capacity of compressive strength in high performance concrete (HSC) with steel fiber addition. To test the performance of the algorithm, a certain percentage were allocated for training of the algorithm, and the rest for test. This was done from 60-40 percent split up to 90-10 percent split for training and testing respectively. Results generated from the model include mean absolute error, root mean squared error, and relative absolute error for each model. It was observed that there was a good correlation between the actual and predicted values, and that errors were relatively low. Utilization of free algorithms in civil engineering construction will enhance the optimization of concrete mixtures. &nbsp

Customized Design of a Proposed Alignment at MAU Yola Campus in Civil 3D Using Nigerian Federal Ministry of Works Highway (FMWH) Manual

This study is aimed at testing the ability of Civil3D to design a carriageway using FMWH Manual, customizing it to suit that purpose. For this purpose, input commands in Civil3D were modified to reflect and accommodate the guidelines outlined in the manual. The route under consideration is a proposed dual carriageway alignment at Modibbo Adama University (MAU) Yola, Adamawa State in the North Eastern part of Nigeria. Scope of work carried out includes both field work (focusing on route survey) and roadway alignment design, subdivided into route location, data acquisition method and geometric design. Data for this project was obtained directly from the field using conventional ground survey method. Google Earth was used to select preliminary control points, GARMIN GPSMAP64 Hand Held GPS Phone was use to record the easting and northing of the control points onsite which serves as a baseline. Theodolite traversing by an analogue theodolite (Kern-Swiss K1-M 292272) was used to tie the control points and to range intermediate points at 25m interval longitudinally along the centerline and perpendicular offset points that were 6m & 12m on both Left and Right of the Centre. Natural Ground Level (NGL) was established from first principle by taking Field Short Data (FSD) of elevation of established point along the baseline using a dumpy level (SUN DSC232) to obtain the true level of the alignment. Plate vial test was carried out on the instruments to ensure accuracy of data recorded. Reduce level was computed using Microsoft excel and the output was imported into the design software (Autodesk Civil 3D V.2023) as a dot csv (.csv) data file known as PENZD.csv. The design of the alignment was carried out using criteria-based design by applying Federal Republic of Nigeria Federal Ministry of Works Highway Manual Part 1 Design Volume 1 Geometric Design (2013). A simple horizontal circular curve with a radius of 200m was designed at chainage 0+268.55 to 0+290.41 between two tangents. Two Sag curves; a crested-sag curve towards the beginning of the alignment at chainage 0+160.95 and a sag curve towards the ends of the alignment at chainage 0+655.33 were designed for the vertical alignment. A trapezoidal channel with a base-width of 0.5m, top-width of 1.1m & a depth of 0.8m was provided alongside the proposed road alignment to discharge storm water. Volume of earthworks was computed as 5548.18m3, and that of fill was found to be 1688.43m3 with a net cut-volume of 3859.75m3. A single cell box culvert was proposed to be sited at chainage 0+524 to 0+532.5. Equally, a pipe culvert was proposed to be sited at 0+722 to 0+723. The results indicate that the designed alignment was adequate and economical based on the proposed data

Characterization of Some Portland Limestone Cements in Nigeria Using Fourier-Transform Infrared Spectroscopy (FTIR)

In Nigeria, the most widely used cement strength class are 32.5 and 42.5 Portland limestone cement. However, due to lack of awareness, scientists and researchers are reporting the use of PLC as Ordinary Portland Cement (OPC). The study presents the characterization of PLC using absorption spectroscopy as well as oxide composition. Ratio between 7 - and 28 - day strengths of some selected PLCs are presented. It is seen that the Brands investigated conforms to the specifications of Portland composite cements in compliance with ASTM C150 and NIS 444-1. Absorption spectrum for the two brands were similar to that of OPC and exhibited similar characteristics. Concrete strength was within the designed concrete specification, and the ration between the two curing ages is 0.6 for both brands

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Progress on the Use of Rice Husk Ash (RHA) as a Construction Material in Nigeria

Research on the use of Rice Husk Ash (RHA) in cement, concrete and mortar has been explored in different fronts in Nigeria with encouraging results. RHA is composed of silica, alumina, iron oxide, calcium oxide and some traces of other compounds. The combustion of RHA at optimum temperature established by researchers produces either amorphous or crystalline ash depending on the combustion temperature and type of burning. This paper tries to bring under one umbrella documented research reported in literature on the use of RHA in construction in Nigeria. Physical and chemical properties; consistency, setting time and flow of mixed paste are reported. Combustion process and optimum temperature has also been exclusively reported. Cement replacement with RHA, strength results on concrete, mortar, bricks and blocks; other properties reported are flexural and tensile strength, sorptivity and coefficient of water absorption

Impact Resistance of High-Performance Steel Fiber Concrete under Long Term Exposure to Environmental Conditions

An investigation is presented here that studied the influence of long-term environmental conditions exposure on cylindrical specimens after initial 28 day moist curing. The specimens were tested after six months subjected to Mediterranean weather elements in North Cyprus. Specimens with 150 mm diameter by 60 mm long cylinders were tested under impact load using a modified version of the testing equipment described in ACI 544.2R. Numbers of blows to create first and damage cracks were determined, and subsequently the impact energies calculated. It was seen that there is as much as twenty times improvement in impact energy of fibered concretes at fiber volume of 2% when compared with plain concrete. This will goa long way to improve the impact resistance of industrial floors and slabs on grade