Scheffe's Simplex Optimization of Flexural Strength of Quarry Dust and Sawdust Ash Pervious Concrete for Sustainable Pavement Construction

Pervious concrete provides a tailored surface course with high permeability properties which permit the easy flow of water through a larger interconnected porous structure to prevent flooding hazards. This paper reports the modeling of the flexural properties of quarry dust (QD) and sawdust ash (SDA) blended green pervious concrete for sustainable road pavement construction using Scheffe's (5,2) optimization approach. The simplex mixture design method was adapted to formulate the mixture proportion to eliminate the set-backs encountered in empirical or trials and the error design approach, which consume more time and resources to design with experimental runs required to evaluate the response function. For the laboratory evaluation exercise, a maximum flexural strength of 3.703 N/mm² was obtained with a mix proportion of 0.435:0.95:0.1:1.55:0.05 for water, cement, QD, coarse aggregate and SDA, respectively. Moreover, the minimal flexural strength response of 2.504 N/mm² was obtained with a mix ratio of 0.6:0.75:0.3:4.1:0.25 for water, cement, QD, coarse aggregate and SDA, respectively. The test of the appropriateness of the developed model was statistically verified using the Student' t-test and an analysis of variance (ANOVA), and was confirmed to be acceptable based on computational outcomes at the 95% confidence interval. Furthermore, the scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) were used to evaluate the morphological and mineralogical behavior of green prior concrete samples with various additive mixture compositions. The addition of QD and SDA, on the other hand, aided the creation of porous microstructures in the concrete matrix due to fabric changes in the concrete mixture, potentially aided by the formation of cementitious compounds such as calcium aluminate hydrate and calcium silicate hydrate.

Concrete Performance Attenuation of Mix Nano-SiO2 and Nano-CaCO3 under High Temperature: A Comprehensive Review

Fire and extreme heat environmental changes can have an impact on concrete performance, and as climate change increases, new concrete structures are being developed. Nano-silica and nano-calcium carbonate have shown excellent performances in modifying concrete due to their large specific surface areas. This review describes the changes in concrete modified with nano-silica (NS) and nano-calcium carbonate (NC), which accelerate the hydration reaction with the cementitious materials to produce more C-S-H, resulting in a denser microstructure and improved mechanical properties and durability of the concrete. The mechanical property decay and visualization of deformation of mixed NS and NC concrete were tested by exposure to high temperatures to investigate the practical application of mixed composite nanomaterials (NC+NS) to concrete. The nano-modified concrete had better overall properties and was heated at 200 °C, 400 °C, 600 °C and 800 °C to relatively improve the mechanical properties of the nano concrete structures. The review concluded that high temperatures of 800 °C to 1000 °C severely damaged the structure of the concrete, reducing the mechanical properties by around 60%, and the dense nano concrete structures were more susceptible to cracking and damage. The high temperature resistance of NS and NC-modified nano concrete was relatively higher than that of normal concrete, with NC concrete being more resistant to damage at high temperatures than the NS samples.

Pavement maintenance management framework for flexible roads: a case study of Pakistan

Roads play a pivotal role in the overall economic growth of any country. Developed countries allocated sufficient budget to make new roads and to maintain the existing roads. They also have a proper pavement management system (PMS) in practice to manage roads, whereas developing countries suffer from budgetary issues to make new roads and maintain the existing road network. Therefore, this paper explores the awareness of PMS via direct and indirect methods in Pakistan with a proposed framework of the low-cost model and pavement maintenance indicators for developing countries. This paper also performs a scientometric assessment of PMS. A detailed literature review has been carried out for this study, followed by a quantitative study from experienced professionals. The scientometric data is collected from the Scopus database from 1975 to 2020, whereas the data for PMS awareness assessment has been collected using questionnaires from different experts working directly and indirectly in the road management sector. The data has been analyzed using the arithmetic mean because of the nature of the questions and scope of the study. The direct method results show that experts are aware of PMS for a new road, but they have no PMS to rehabilitate roads. The indirect method results show that the authorities are applying various components of PMS, but there is no proper PMS in practice. This paper helps decision-makers to make better decisions and policies for improved road maintenance and rehabilitation. The proposed framework in the study can significantly assist the UN-SDG 9 (Facilitate Sustainable Infrastructure in Developing Countries) and 11 (Affordable and Sustainable Transport System).

Evaluation and Comparison of Mechanical Properties of Polymer-Modified Asphalt Mixtures

Polymer modification is extensively used in the Kingdom of Saudi Arabia (KSA) because the available asphalt cement does not satisfy the high-temperature requirements. It was widely used in KSA for more than two decades, and there is little information regarding the differences in the performance of different polymers approved for binder modification. Pavement engineers require performance comparisons among various polymers to select the best polymer for modification rather than make their selection based on satisfying binder specifications. Furthermore, the mechanical properties can help select polymer type, producing mixes of better resistance to specific pavement distresses. The study objective was to compare the mechanical properties of the various polymer-modified asphalt (PMA) mixtures that are widely used in the Riyadh region. Control mix and five other mixes with different polymers (Lucolast 7010, Anglomak 2144, Pavflex140, SBS KTR 401, and EE-2) were prepared. PMA mixtures were evaluated through different mechanical tests, including dynamic modulus, flow number, Hamburg wheel tracking, and indirect tensile strength. The results show an improvement in mechanical properties for all PMA mixtures relative to the control mixture. Based on the overall comparison, the asphalt mixture with polymer Anglomk2144 was ranked the best performing mixture, followed by Paveflex140 and EE-2.

A cross sectional study of newborn care practices in Gilgit, Pakistan

OBJECTIVE

The purpose of this article is to explore the traditional newborn-care beliefs and practices and to identify factors that affect newborn health, aiming to design an appropriate, culturally-sensitive and acceptable intervention to reduce neonatal morbidity and mortality.

METHODS

A cross sectional study was conducted in the district of Gilgit in Pakistan. A structured questionnaire was administered to 708 mothers who gave birth to a live child in the past one year. Descriptive and inferential analysis was performed to identify socio-economic and health care factors associated with newborn care practices.

RESULTS

Illiterate mothers were more likely to use harmful newborn care practices, while those seeking health care from private sector were less likely to use harmful newborn care practices. Ninety-four percent of the newborns were given a bath soon after birth, likelihood to be 2 times more amongst illiterate mothers. Cord application was a very common practice, mostly with matti (crashed apricot seed), and a majority of the mothers reported newborn massage generally with mustard oil. The administration of colostrum as the first feed was relatively common in the study area. Twenty-seven percent of mothers reported giving pre-lacteals; from which prominent feeds included salt water (44%) and cow's milk (26%). Initiation of breastfeeding within 1 hour after birth was (71%), while (29%) reported to breastfeed their newborn within 24 hours. Thirty-seven percent newborns were exclusively breastfed for six months.

CONCLUSION

This study underscores the existence and predominance of risky practices in newborn care; that stresses the need for health education programs to ensure safety of the newborn.

A cross sectional survey of newborn care practices in rural Sindh, Pakistan: implications for research and policy

INTRODUCTION

Of annual four million neonatal deaths, majority in the developing world, approximately three-quarters die within the first week of life. Pakistan has one of the highest newborn mortality rates.

STUDY DESIGN

We conducted a cross sectional study to assess knowledge, attitudes and practices of women of reproductive age in rural Pakistan.

RESULTS

Of 1490 mothers interviewed, prevalence of newborn care practices ranged between 32% (early bathing of newborn) and 69% (use of traditional cord applications). Uptake of antenatal care services was identified as a strong predictor of good newborn care after controlling for skilled birth attendance, socio-economic status, age of mother and sex of infant (OR = 1.26; 95% CI: 1.00-1.57).

CONCLUSIONS

The association of uptake of antenatal care services with good newborn care highlights the necessity to improve coverage of services with the integration of counseling about newborn care in order to reduce the burden of neonatal morbidity and mortality.

The Use Of Photogrammetry Techniques To Evaluate The Construction Project Progress

The modeling of 3D objects from image sequence is a challenging problem and has been an important research topic in the areas of photogrammetry and computer vision for many years. Photogrammetry is the science of calculating 3D object co–ordinates from image and provides a flexible and robust approach for measuring the static and dynamic characteristics for construction management. This paper discusses the experience in Construction Technology and Management Centre (CTMC), Universiti Teknologi Malaysia (UTM) in adapting photogrammetry methods for specific problems in the construction industry and outlines the principles of close–range photogrammetry in evaluating the progress of construction projects. There is a need to use the principles of close–range photogrammetry to evaluate the progress of construction project and to develop the actual progress bar chart. The fundamental task of photogrammetry is to rigorously establish the geometric relationship between the image and the object, as it existed at the time of imaging event. One such software application is PhotoModeler Pro version from the Canadian company Eos System has been suggested to extract the 3D features from 2D images. The approach described in this paper demonstrates the use of digital photogrammetry as a complementary method, which describes the 3D features extraction procedure in detail and highlights the qualitative control that can be achieved during the construction. The technique uses mainly off–the–shelf digitalcamer and software technologies that are affordable to most organisations and able to provide acceptable accuracy. Key words: Close–range photogrammetry, digital photographs, 3D–coordinates, software and digital monitoring system