NFRP strengthening of reinforced concrete beams

Publisher PD

Recycling of Periwinkle Shell Waste as Partial Substitute for Sand and Stone Dust in Lightweight Hollow Sandcrete Blocks towards Environmental Sustainability

Global consumption of nonrenewable natural aggregate for construction activities is now becoming a significant concern. Reusing agricultural or marine-based wastes could offer a promising alternative to achieve natural aggregate conservation and a pollution-free environment. This study investigated the suitability of using crushed periwinkle shell (CPWS) as a reliable constituent material for sand and stone dust in producing hollow sandcrete blocks. The CPWS was used to partially substitute river sand and stone dust at 5, 10, 15 and 20% in sandcrete block mixes using a constant water–cement ratio (w/c) of 0.35. The weight, density and compressive strength of the hardened hollow sandcrete samples were determined after 28 days of curing along with the water absorption rate. Results showed an increase in the water absorbing rate of the sandcrete blocks as CPWS content increased. Mixes containing 5% and 10% CPWS substitute for sand with 100% stone dust surpassed the minimum targeted strength of 2.5 N/mm2. The compressive strength results suggested that CPWS is most suitable to be deployed as a partial substitute for sand as a constant stone dust material, thus imply that the construction industry can achieve sustainable construction with agro or marine-based wastes in hollow sandcrete production

Dataset on ground radiometric survey in part of the Eastern Dahomey Basin, SW Nigeria

The dataset for this article contains the measured activity concentration of radionuclides and gamma-radiation dose rate obtained from the radiometric survey in Ota, Ado-Odo Local Government Area, Ogun State, Nigeria. The data were manually collected in fifty (50) locations using the Super SPEC RS-125 spectrometer for about three (3) weeks in January, 2017. The descriptive statistical analysis of the data were equally explored for possible statistical relationships. The field dataset is made available publicly for further extended analyses that can provide insights into the safety status of the study area from radiological health concerns. The dataset could also serve as a significant baseline radiometric data for future epidemiology researches and monitoring initiative in Ota and its environs. Keywords: SPEC RS-125, Radiometric survey, Natural radionuclides, Gamma-radiation dose rate, Southwestern Nigeri

Experimental Investigation on the Effect of Elevated Temperature on Compressive Strength of Concrete Containing Waste Glass Powder

This study examines the effect of elevated temperature on the strength of concrete containing glass powder (GWP) as Ordinary Portland cement replacement. The cement was partially replaced by 0, 15, 18, 21, 24, 27 and 30 % of GWP and samples were prepared at constant water-binder ratio of 0.5. The cube samples after curing in water for 90 days were exposed to 60, 150, 300 and 500°C temperatures increased at a heating rate of 10°C/min. Compressive strength values were measured on unheated samples and after air-cooling period of the heated samples. Scanning electron microscope (SEM) was carried out on selected samples to examine alterations in the matrix and interface. The results indicate a decrease in the compressive strength with increasing temperature, and significant alteration was observed in the concrete matrix and interface from the SEM analyses. However, the results indicate that concrete samples containing 21% GWP exhibit higher strength compared to control

Potentials of Momordica angustisepala fiber in enhancing strengths of normal portland cement concrete

Presence of cracks in concrete affect the integrity. It reduces the life expectancy of concrete structures and is often responsible for collapse of structures, especially in the developing nations. At the root of these cracks is the very low tensile strength of concrete. Various techniques have been suggested for the enhancing the tensile strength, among which is the use of discontinuous micro fibers of various nature. This research investigated the use of Momordica angustisepala (Ma) fiber to enhance concrete strength. Concrete containing coconut fiber was adopted as a control. Slump test, air entrainment test, compression test and split tensile test were carried out on specimens. Results of the research indicate that an optimum Momordica angustisepala fiber contents of 0.25 and 0.5% enhanced respectively the compressive strength by 4.37% and the tensile strength by 10%. The results clearly show that this renewable material has the potential to enhance the compressive and tensile strengths of concrete

Effects of Different Curing Methods on the Strength Development of Concrete Containing Waste Glass as Substitute for Natural Aggregate

Concrete curing is fundamental to achieve quality and durable concrete. This study examines the influence of curing methods on the mechanical strength development of concrete comprises of waste soda lime glass pulverized into fine and coarse aggregate sizes as partial and complete replacement for natural aggregates in concrete. The primary variables considered are the curing methods. The glass content was varied in steps of 25% by weight from 0 – 100% to replace both natural fine and coarse aggregate in the concrete mixes. Concrete mixes were batched using a mix ratio of 1:2:4 (cement: sand: granite) at water-binder ratio of 0.5 targeting a moderate strength of 20 MPa. Forty-five (45) number concrete cubes and cylinders were cast and tested after 7, 14 and 28 days of curing using two curing methods; namely plastic membrane sheet covering and total immersion in water.  The results obtained clearly indicate that waste glass concrete cured by complete immersion in water showed better performance in strength development than those cured by plastic membrane covering. Generally, the results indicate that concrete mix produced with 25% glass content exhibit significant strength that compared well with the control at 28 days of curing

Experimental datasets on properties of river sand as an aggregate in replacement of crushed rock for interlocking stones production

The data explored the assessment of the quality of river sand as an aggregate in replacement of crushed stones which are widely used by majority of manufacturers in production of interlocking stones. Experimental tests carried out on river sand and crushed rock as aggregates include: Grain size distribution, Specific gravity, moisture content determination and Bulk density to determine the quality behavior parameters and (compressive strength) to determine the strength parameters. The data of the experiments are presented in Tables and Bar charts. Keywords: River sand, Crushed stone as fine aggregate, Cement, Compressive strength, Experimental procedure

Experimental datasets on properties of river sand as an aggregate in replacement of crushed rock for interlocking stones production

The data explored the assessment of the quality of river sand as an aggregate in replacement of crushed stones which are widely used by majority of manufacturers in production of interlocking stones. Experimental tests carried out on river sand and crushed rock as aggregates include: Grain size distribution, Specific gravity, moisture content determination and Bulk density to determine the quality behavior parameters and (compressive strength) to determine the strength parameters. The data of the experiments are presented in Tables and Bar charts. Keywords: River sand, Crushed stone as fine aggregate, Cement, Compressive strength, Experimental procedure