Walid A. Al-Kutti

The purpose of this study is to study the life cycle assessment of biocementitious materials production in comparison to traditional cement materials production. The environmental impact of production processes over the life cycle was evaluated on the basis of global warming and ozone depletion, human health, land, freshwater, marine ecotoxicity, and natural water system eutrophication. LCA uses endpoint methods (ECO indicators) and SimaPro 8 software to assess the health and environmental impact of raw materials used in the production process, including cement, Ca(NO₃)₂·4H₂O, urea, molasses, and electricity. The results showed that cement materials made 82.88% of the world’s warming in all raw materials used in production processes, 87.24% of the world’s health, 89.54% of the deforestation of freshwater, and 30.48% to marine eutrophication. Ca(NO₃)₂·4H₂O contributes by 58.88% to ozone depletion, 15.37 to human carcinogenic toxicity, 3.19% to freshwater eutrophication, and 11.76% to marine eutrophication. In contrast, urea contributes 38.15% to marine eutrophication and 5.25% to freshwater eutrophication. Molasses contribute by 13.77% to marine eutrophication. Cement contributes 74.27% to human health damage, 79.36% to ecosystem damage; Ca(NO₃)₂·4H₂O contributes 13.54% to human health damage and 9.99% to ecosystem damage; while urea contributes 6.5% to human health damage and 5.91% to ecosystem damage. Bio-cementitious wastewater should undergo a treatment process to remove urea and molasses residues, as well as nitrates, before final disposal into the environment.

The seismic hazard of vulnerable regions warrants the investigation of new technologies, such as base level isolation by lead rubber bearing (LRB) devices, that can help to mitigate structural damage on seismic prone buildings. The behavior adopting such technologies can be dynamically observed in simulated environments and thus serves as a valuable metric for their feasibility. LRB base isolators were incorporated into the design of 16 model buildings to better understand how they affected a building’s seismic response while also providing information on the structural parameters. A total of 12 different types of bearing systems were tested in base isolated (BI) buildings against conventional fixed-base (FB) isolated buildings. The system of each model high-rise building was represented by the finite element package. Static as well as dynamic analysis were conducted using response spectrum analysis (RSA) based on the seismic excitation to determine the influence of the model type in the aseismic design and the alteration in superstructure behavior. The study reveals that the LRB isolators can potentially diminish respective story accelerations, story inertia, and base shear. Use of LRB isolators in BI buildings resulted in a 10–20% reduction in base shear compared to FB buildings. A notable lateral shift of superstructure is offered by LRB-induced flexibility. The reduction of story acceleration for response spectrum varies 30% on lower stories up to 70% on upper stories. The LRB systems with higher characteristic strength and relatively less isolation periods shows better productivity to minimize displacements in the bearing face for dropping structural shift. However, the LRB with comparatively lower characteristic strength and high isolation periods shows the most efficiency in controlling base shear, offering least story accelerations and consenting lower story inertia forces.

Cement manufacturing is indeed a major contributor to global warming that involves energy-intensive production processes along with emitting huge greenhouse gasses into the atmosphere. To adopt sustainable construction practices, agro-industrial waste materials as supplementary cementitious materials (SCMs) have been used by numerous researchers to partially replace conventional ordinary Portland cement (OPC) with SCMs by evaluating its optimum replacement dosage. This study aims to: (1) highlight the background of the date palm tree and the application of date palm waste as a construction material; (2) optimizing the dosage of date palm ash (DPA) as a cementitious material, at the replacement level of 10%, 20%, and 30%; and (3) understand the reaction kinetics by way of characterization techniques. DPA-based binary mixes were compared with each other and with the control (100% OPC mix) through fresh, mechanical, durability, and microstructural properties. The mechanism of reaction at early- and long-term period of curing was studied by characterization tests on paste, including nitrogen adsorption test (BET), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR). The outcome revealed 10% DPA as a strong and durable substitute to OPC, by formation of more Calcium Silicate Hydrate (C-S-H) and Calcium Aluminosilicate Hydrate (C-A-S-H) gel, whereas up to 30% DPA replacement can further maximize clinker replacement with reasonable performance, together with enhanced sustainability and reduced construction cost.

This paper explores the possibility to use Drucker-Prager model in Steel-Concrete composite section. Numerical simulation was conducted using finite element package to simulate the steel-concrete composite section subjected to uniaxial compressive loading. After calibration with experimental study, parametric study was conducted to evaluate the effect of the friction angle and the cohesion constant c on the stress-strain curve of composite section. Empirical relationship between the friction angle and the confined concrete compressive strength was developed and a range of cohesion constant c between 5-10 MPa was suggested for confined concrete strength range of 25 to 100 MPa, respectively.

This study investigates the durability of partially-damaged concrete with the addition of Silica Fume and Ground Granulated Blast Furnace Slag. Portland cement was replaced by 10% SF and 60% of GGBFS as a replacement of Portland cement. Thirty-six concrete cylinders (100 x 200 mm) were subjected to three compressive loading levels (50%, 75%, and 90% of its ultimate strength capacity). After 28 days of curing, the concrete specimens were experimentally tested for electrical resistivity, rapid chloride penetration (RCPT) and chloride migration coefficient (D_nssm) according to NT-BUILD 494. The experimental results showed that the GGBFS improves significantly the durability of concrete with the highest electrical resistivity and lowest chloride permeability compared to control and SF concrete and both SF and GGBFS had significant effect the concrete durability properties even when the concrete was subjected to compressive damage up to 90% of the compressive strength. A correlation between D_nssm and RCPT in partially damaged concrete was observed and an empirical linear relationship was developed to estimate D_nssm.

Concrete anchors are extensively used in the construction industry. Their applications range from erecting permanent objects such as sign poles, direction signs, lighting poles, and so on, to temporary support structures. Several destructive testing equipment types exist in the industry that can be used to evaluate the load-carrying capacity of concrete anchors. However, no nondestructive testing method has been proposed that can estimate their load-carrying capacity. This study develops a new relationship between the pull-out load-carrying capacity, P, of concrete anchors and Schmidt hammer rebound value, R. It was observed from experimentation that the load-carrying capacity of the concrete anchors depends on the embedment length, anchor diameter, concrete strength, and anchor alignment. The effect of anchor alignment was also observed during experimentation, and anchors with ill alignment of more than 5% can lead to lower load-carrying capacity. In addition, it is also possible to identify the ...

Factors such as poor design, bad workmanship and a harsh environment can combine to cause deterioration within a concrete structure leading to visually unacceptable surface cracking or spalling of concrete cover [. In aggressive environments, corrosion of steel reinforcing bars is responsible for major deteriorations in concrete structures. Reduction in bar diameter leads to a lower resistance, which can result in brittle failure of the bar. Initiation and progression of reinforcing steel corrosion can lead to progressive weakening of the structure due to damage accumulation over a period of time, or in sudden catastrophic failures, such as the Berlin Congress Hall, a parking garage in Minnesota [. Antonaci et al. [ conducted an experimental study on different concrete cylinders damaged in compression followed by means of linear and nonlinear ultrasonic methods. Arndt et al. [ tested a concrete slab representing typical bridge decks in order to evaluate the ability of NDT methods to detect different phases of corrosion progression in concrete. Reinforced concrete beam-shaped samples were tested by Aveldano and Ortega [ in order to characterize concrete cracking due to reinforcing corrosion under different environments. Shah and Ribakov [ performed nonlinear ultrasonic testing of cubic concrete specimens with different frequency transducers. Al-Amoudi et al. [ investgated the relatioship between compressive strength of ordinary concrete and blended cement concrete with durability propeties of concrete samples and conculded that the addition of blended cement will improve the performance of concrete in ressiting corrosion of reinforcement. The main objective of this study is to investigate the effectiveness of using nondestructive testing to assess the performance of different types of concrete such as OPC and SFC. Also, to correlate different types of nondestructive testing and to investigate the possibility of capturing the occurrence of corrosion in reinforcing bars in concrete.