This comprehensive study investigates the mechanical properties of self-compacted lightweight concrete (LW-SCC) manufactured with Light Expanded Clay Aggregate (LECA) and modified with various mineral additives including lime powder (LP), marble dust (MD), fly ash (FA), and granulated quartz (GQ) at different percentages (10%, 20%, and 30% by weight of cementitious materials). Fourteen concrete mixtures were prepared and evaluated for both fresh and hardened properties. Fresh properties were assessed through flow diameter, T500, J-ring, Lbox, and V-funnel tests, while hardened properties including density, compressive strength, splitting tensile strength, flexural strength, and bond strength were determined at 7, 28, and 56 days. Results demonstrate significant improvements in mechanical properties with the incorporation of mineral additives. LECA concrete containing 10% lime powder exhibited 25% higher compressive strength than the control mix with silica fume. Marble dust at 20% provided optimal mechanical performance with a 35% increase in compressive strength and a 37% improvement in tensile strength. Fly ash showed progressive enhancement in mechanical properties with increasing content, achieving a 15% improvement in compressive strength at 30% replacement. Granulated quartz was most effective at 10% content, delivering 20% higher compressive strength and the highest bond strength improvement of 52.63% at 7 days. All mixtures maintained lightweight characteristics with densities between 1.70-1.75 t/m3. Fresh concrete properties improved with increasing mineral additive content, with enhanced flowability and passing ability. This research establishes that LECA can effectively produce structural lightweight self-compacted concrete with significantly enhanced mechanical properties through the strategic incorporation of mineral additives, offering promising applications in sustainable construction.

This study investigates the effects of incorporating various mineral additives on the durability characteristics of self-compacted lightweight concrete manufactured with Light Expanded Clay Aggregate (LECA). The research evaluates the performance of different mineral additives including lime powder (LP), marble dust (MD), fly ash (FA), and granulated quartz (GQ) at varying proportions (10%, 20%, and 30% of cementitious materials). Comprehensive durability assessments were conducted through multiple testing regimes including resistance to sulfate attack, chloride attack, freeze-thaw cycles, water permeability, and water absorption. The results demonstrate that the incorporation of mineral additives significantly enhances the durability properties of LECA concrete. Marble dust at 20% shows superior performance against sulfate attack with only 12.21% reduction in flexural strength compared to 17.62% for the control mix. Granulated quartz at 10% exhibits excellent resistance to chloride attack, while fly ash demonstrates progressively improved resistance to both sulfate and chloride attacks with increasing percentages up to 30%. The incorporation of 20% marble dust results in a 60% reduction in water permeability, while 30% fly ash concrete shows a remarkable 40.18% decrease in water absorption compared to the control mix. All LECA concrete samples maintain chloride and sulfate content within acceptable limits according to industry standards. The findings establish that the strategic incorporation of mineral additives, particularly marble dust and fly ash, substantially enhances the durability characteristics of self-compacted lightweight concrete, making it suitable for applications in aggressive environmental conditions.

The construction demolition is non-degradable. Recycled aggregates were utilized to create sustainable products in pervious concrete manufacture. Adding fibers enhances pervious concrete mechanical properties. High absorption of Recycled aggregate (RA) and polyethylene-glycol are used to ensure internal curing. The purpose of this study was to statistically improve the mechanical properties of pervious concrete based on an experimental investigation. Taguchi method was employed to present DOE (Design of Experiment). Five factors in four levels designed by Taguchi provide sixteen mixes (L16 array). The factors were the replacement of coarse aggregates by recycled aggregates, W/C ratio, synthetic macro-fiber, steel fiber and polyethylene-glycol. Designed mixes were prepared. Taguchi's analysis concluded; that macro-fiber addition has no impact on mechanical properties. Using a ratio of 10% recycled aggregates replacement was the optimum ratio. Taguchi prediction of optimum mixes was experimented with using mixes. Confirmation test results agree with the predicted values within +/- 10%.

This study investigates the impact of openings on the behavior of arched beams and the effectiveness of different strengthening materials in enhancing their performance. The study involves three stages. The first stage focuses on the effect of openings on the behavior of curved beams. The second stage examines the effect of different strengthening materials, including carbon fiber sheets, glass fiber sheets, and steel plates, on the deflection and failure load in the presence of openings. In the third stage, Finite Element models are used to simulate the tested beams with different strengthening materials, and the differences between beams with and without openings are analyzed. The results show that the presence of openings negatively affects the ultimate load, deflection, and ductility ratio of arched beams. Regarding strengthening, beams strengthened with steel plates demonstrate a higher ultimate load, approximately 5.6% and 21% higher than beams strengthened with carbon fiber and glass fiber sheets, respectively. Moreover, the deflection of beams strengthened with steel plates is 6.4% and 8.9% higher than beams strengthened with CFRP and GFRP. The presented work is introduced to offer a valuable solution to some developed systems for controlling, repairing, and supporting structures.

Construction engineering in coastal areas is facing the challenge of a shortage of fresh water for mixing and curing. The quality of water places an important role in the setting and strength development of concrete structures. This research aims to study the feasibility of using seawater to cast and curing plain concrete for non-structural uses. Samples were cast using tap water or seawater and then cured using tap water or seawater up to testing ages. Concrete properties were studied in terms of compressive, tensile, flexure, and bond strengths at 7, 28, and 56 days of age. Test results showed that the self-curing concrete with PEG performed better in hardened properties compared to conventional concrete. The compressive strength and subsequently the other related strengths of concrete were shown to increase for specimens mixed and cured in seawater at early ages up to 7 days, while a definite decrease in the respective strengths was observed for ages more than 28 days and up to 56 days. The reduction in strength increases with an increase in exposure time, which may be due to salt crystallization formation affecting the strength gain.

The behavior of fibrous high-strength self-compacting concrete flat slabs in punching shear either with or without shear reinforcement is investigated experimentally and analytically in this research. Steel and basalt fibers were used in this study. A Finite-Element (FE) analysis is performed using the ANSYS program to simulate the experimental work. Experimental and FE results were highly compatible. The results were compared with various codes (ECP, ACI, and EC-2). The code provisions produced results not close to the test results of fibrous concrete. This research presented an updated empirical equation for the punching shear capacity for fibrous reinforced flat slabs.

Geopolymer concrete is considered eco-friendly concrete.In this research, the replacement of cement in concrete using Palm fronds ash and red brick powder is studied.The Geopolymer concrete control specimens were tested in terms of compressive, splitting tensile, and flexural strengths at different ages.The main variables are the effect of the elevated temperatures (200, 400, and 600 o C for 2 hours) and cooling methods (air-water).The samples were heated then, the specimens were cooled by using two regimes, left in air for one day or by immerging in water for one day.Then the samples were tested to obtain compressive and splitting tensile strength.Test results indicated that for specimens cooled in the air, the samples exposed to 200 and 400 o C as elevated temperatures, the compressive strength values increased by about 7.30% and 10.15%, respectively, and the tensile strength values increased by about 6.7% and 8.68 %, respectively.As samples were exposed to 600°C, the compressive and splitting tensile strength decreased by about 43.7 % and 44.65 %, respectively.For specimens cooled in water and exposed to 200 and 400 o C, the compressive strength values increased by about 4.54% and 7.40%, respectively, and the tensile strength values increased by about 4.16% and 6.5 %, respectively.In the specimens exposed to 600°C, the compressive and splitting tensile strength decreased by about 46.2 % and 46.4 %, respectively.

Self-curing concrete is one of the important new types of concrete due to the scarcity of water especially, in the desert areas.Recycling waste demolitions as coarse aggregates for concrete is one of the recent solutions to reduce its bad impact on the environment.In this research, the both types will be combined.This research aims to investigate the behavior of recycled aggregate self-curing concrete under elevated temperatures.The main variables are; aggregate types (recycled vs. natural), elevated temperatures (200 o C, 400 o C, and 600 o C), cooling methods (in the air or by using water), and storage time after cooling (for 1 or 28 days).Results are driven in terms of compressive, splitting tensile, flexure, and bond strengths.Test results showed that the recycled aggregate self-curing concrete could be used under elevated temperature considering a strength loss.The use of self-curing and recycled aggregate self-curing concrete may be considered as an alternative solution to the use of conventional curing concrete for infrastructures.Using crushed ceramics as a coarse aggregate at elevated temperature is efficient.The use of recycled aggregate self-curing concrete may consider as an alternative solution to the use of conventionally cured concrete in infrastructures.Firefighting is not recommended by using water due to its bad effects after cooling.

This paper presents the major causes of deterioration and discusses the factors, which can improve the durability of concrete structures. This paper also presents the results of an extensive experimental investigation for the reuse of industrial by product materials such as blast furnace slag (BFS) and silica fume (SF) in producing high performance concrete. Producing of high strength concrete has a worthy priority field of study worldwide, their production is largely expanded the last two decades. Potential applications of light weight high strength concrete are in producing thin durable sections and in strengthening and repairing defaulted structures. It is shown that it is possible to develop a concrete matrix of high strength and excellent durability by taking the advantage of the interactions of cementitious system and the Portland-cement slag system is shown to offer a good example of this nature. However, development of light weight strength and performance concrete will be necessary to protect the concrete from aggressive and unfriendly environmental and climatic conditions. Lightweight concrete can significantly reduce a dead load of structural concrete elements compared to normal-weight concrete. Self-curing concrete is one of the innovative concretes that can be cured without using conventional curing regimes. Lightweight concrete is made from lightweight coarse aggregates instead of natural coarse aggregates. It has gained popularity due to its lower density and superior thermal insulation properties. In this investigation, the durability of lightweight self-curing concrete under the attack of sulfates and chlorides was studied. The effects of sulfates (as 20% concentrated sodium sulfates solution) on compressive, splitting tensile and flexure strengths after different ages (2, 4, and 6 months) were studied. The effects of chloride attack (as 20% concentrated sodium chloride solution) were studied on bond and flexure strengths after two ages (2 and 4 months). Also, the flexure behavior of the lightweight aggregate self-curing reinforced concrete beams is studied under a four-point load system before and after chloride attack. Test results indicated that dolomite then crushed concrete followed by Addibor can be used as coarse aggregates for structural self-curing concrete under chlorides or sulfates Using lightweight aggregates (Addipor-55) or lightweight bricks as a replacement of dolomite can be used to produces lightweight self-curing concrete with satisfied durability characteristics under chlorides or sulfate attack.

Various challenges encountered in the construction industry have led to the production of concrete, with not just high strength, but also with enhanced durability properties. This study investigates the performance and durability of hardened high strength concrete cast using Nano-silica, silica fume and fly ash. Experiments were conducted by substituting cement by weight with Nano-silica, silica fume or fly ash with ratios of 5 %, 10% and 15% and compared to a control mix. The durability performance of the high strength concrete, in terms of water permeability, sulfates resistance, chloride resistance and freeze-thawing tests were tested. This study generally proposes a sustainable solution to produce durable concrete that could have useful application in the construction industry. Based on the results obtained, the hardened properties of concrete improved depending on the type of supplementary cementious materials. Test results showed that Nano-silica has a great influence on concrete properties, but the high dosage show a reverse result.

Hot climates prevail in many regions of the globe. The average summer temperature of hot arid areas is in the range of 40-50 degrees C with temperatures exceeding these values under direct solar radiation. Curing concrete in these regions may be challenging due to limited availability of suitable water for curing and/or rapid loss of curing water by evaporation. For many years self-curing admixtures were recommended as an alternative to water curing, however, limited studies have been conducted on their performance in hot weather conditions. In this investigation, the effects of a hot climate on the fresh and hardened properties of self-curing (SC) concrete and normal conventional concrete (NC) in hot weather were studied. A water-soluble polymer self-curing agent, polyethylene glycol (PEG 400), was added to the SC mixes. The testing parameters were concrete dry materials (25 or 50 degrees C) and/or mix water temperatures (5, 20 or 35 degrees C) at the time of mixing. NC samples were continuously water cured at 25 or 50 degrees C, whereas the SC ones were air cured at the same temperatures. The tested properties were workability, compressive strength, splitting tensile strength, and flexural strength. It was found that SC outperformed NC under varying conditions. The results could not be simply attributed to the retention of mix water by the self-curing admixture. A more comprehensive explanation for the observations is proposed. (C) 2020 Elsevier Ltd. All rights reserved.

Concrete-encased steel beams (CESB) have become one of the fundamental composite members utilized in recent years. The research aims to investigate the effect of strengthening CESB with and without openings. Eleven simply supported fully CESB beams with and without web opening under static loading using a four-point loading system were studied. Two main stages were considered; studying the effect of the presence of web opening (located in the shear zone), and the effect of applying three different strengthening materials on the flexure or the shear zone of the beams on the behavior of the CESB. Carbon fiber-reinforced polymer wraps, glass fiber-reinforced polymer wraps, and steel plates were used as externally bonded reinforcement strengthening materials. The obtained experimental results were the mode of failure, the crack pattern, load–deflection curve at mid-span, load–strain curves at different locations, first crack load, serviceability load, ultimate load, energy absorption, and ductility ratio. A Finite-Element Analysis (FEA) is performed using ANSYS release 19.0 program to simulate the 11 tested specimens. Test outcomes showed that the ultimate load and its corresponding deflection decreased by about 58.28% and 80.17%, respectively, due to the effect of the web opening. Furthermore, shear strengthening of CESB with web opening located in the shear zone is more effective than the flexural strengthening using the three different strengthening materials. Also, using a steel plate is extra effective than using carbon fiber wraps or glass fiber wraps on the performance of the tested beams. Based on the FEA, high compatibility between both FE and experimental results is achieved.

The main aim of this research is studying the effect of hot weather on the properties of self-compacting concrete and conventional concrete in both fresh and hardened state. Also, this research extends to improve the behavior of self-compacting concrete in hot weather. The main parameters were surrounding weather temperature (5°C, 20°C and 35°C), concrete materials temperatures’ (25°C, 50°C), curing temperatures (25°C and 50°C) and admixtures (using a retarder). Two stages were carried out to achieve the research aim. The behavior of self-compacting concrete compared to conventional concrete was evaluated in the first stage. Based on the first stage, attempts to enhance the concrete properties were evaluated in the second stage. Precautions on mixing and placing concrete in these climates are considered. Results are a drive in terms of; workability tests, compressive strength, splitting tensile strength, and flexural strength. Test results showed that self-compacting concrete behavior and strengths were better than conventional concrete. Slump test, J-ring and V-funnel test were used to evaluate the fresh properties of the self-compacting concrete. Drying shrinkage of self-compacting concrete in hot weather were also evaluated.

Lightweight concrete is an excellent alternative in terms of decreasing the dead load of the structure, while self-compacting concrete eases the pouring and compaction during construction. Combining the advantages of both types is a new field of research. Considering its lightweight structure and ease of placement, lightweight self-compacting concrete may be the answer to the increasing construction requirements of heavily reinforced structural elements. The main variables in this research are lightweight expanded clay aggregate LECA replacement ratio, using superplasticizers. The proposed approach is based on the modified mix design and incorporates the possibilities to realize a LW-SCC in function of two major parameters: density class and compressive strength class. To accomplish this, a total of 12 concrete mixes were used. Tests were performed on concrete specimens to determine the compressive strength, modulus of elasticity, and tensile strength. The unit weight was also measured. These tests provided an understanding of the behaviour of lightweight self-compact concretes under chloride or sulfates attacking. Results indicated that the better strength obtained as using a replacement ratio of 50% with a lower weight by about 30% compared to normal weight self-compacted concrete. Also, it showed that it is possible to manufacturing structural lightweight concrete self-compacting with sufficient durability. Hence it can be used for construction purposes and precast concrete elements with a moderate cost and satisfaction strength.

Pervious concrete is a special concrete type with no or little fine aggregates and a high porosity. It is used for concrete flat applications allows water from rainfall and extra water from other sources to pass directly through. Also, it is considered as porous and permeable concrete. Nowadays the recycled aggregates become one of the solutions to reduce the bad environmental impacts of demolished wastes. This research studied the use of recycled aggregates to cast the pervious concrete. It is conducted in two stages. The first is achieved to investigate the behavior of pervious concrete when cast using recycled aggregates compared to cast using natural aggregates. The second stage aims to study the durability of this type under the attack of sulfates and chlorides. The main variables in the first stage are the aggregate type and slab reinforcement. The main variables in the second stage are the aggregate type, attack type, attack period. Results show that using coarse recycled aggregate is efficient enough comparing to coarse natural aggregates to cast pervious concrete, especially when using crushed concrete. The use of pervious concrete cast using recycled crushed concrete may be considered as an alternative solution to the use of conventional pervious concrete in infrastructures.

This research aims to study the feasibility of repair and strengthening of timber cantilever beams used in historic buildings. It is conducted to investigate the feasibility of using different valid materials and techniques to repair and strengthen timber cantilever beams in new and historic timber buildings. The study is performed in terms of structural performance as well as historic and architectural values. An experimental program of several different materials and techniques is executed. The results are driven in terms of initial cracking load, crack propagation for the tested samples at different loading stages, deflection values, and failure load for each repaired or strengthened material and technique. The main variables are timber types (new and historic), repair and strengthening materials (steel plates, Glass Fiber Reinforced Polymer wrap, and Carbon Fiber Reinforced Polymer laminates), repair or strengthening techniques (near surface mounted and externally bonded system), and cantilever length (1000 and 1250mm). Test results indicated that using steel plates, glass fiber wrap, and carbon fiber laminates increases the value of failure loads and decreases the deflection at both; repaired and strengthened timber cantilever beams compared to control beams.

Self-compacting concrete is used when compaction of concrete is difficult to execute. To use a type of concrete, which does not need conventional curing, self-curing concrete can be used. The combination of those two types together provides a suitable solution for the curing and compacting processes. This research aims to study the feasibility of obtaining normal and high self-curing self-compacting concrete using different curing agents. The effects of curing agents on the behavior of normal and high-strength self-curing self-compacting concrete were studied. This research consists of two stages. The first stage conducted to investigate the effect of curing agent on the main properties of normal-strength and high-strength self-compacted concrete to obtain self-curing self-compacting concrete. The main variables are; concrete grade, curing agent type, and dosage. The second stage was conducted to investigate the behavior of reinforced concrete beams cast using the suggested two concrete types. The results were driven in terms of initial cracking loads, ultimate loads, and crack patterns of testing beams. Results indicate that the both types used, normal-strength and high-strength self-curing self-compacting concrete are efficient in structural elements, which the curing and compacting processes are missing. Curing agents reduce the water evaporation from self-compacting concrete, and hence increase the water retention capacity of self-compacting concretes with sufficient hardened concrete properties.

Lightweight concrete (LWC) has been successfully used since the ancient Roman times. It has gained its popularity due to its lower density and superior thermal insulation properties. LWC can significantly reduce a dead load of structural concrete elements compared to normal weight concrete. Concrete cast using recycled aggregates considered as green concretes as their positive impact on the environment. This research conducted to study the efficiency of obtaining structural LWC cast using recycled aggregates as coarse aggregates. In this research, the main variables are; type of recycled coarse aggregates used (crushed light brick, crushed glass, and crushed red brick compared to dolomite), the dosage of Lightweight aggregate used (ADDIPOR-55 as 0, 10, 20 and 30% of coarse aggregate volume). The investigated physical properties included the unit weight and slump values as well as the main mechanical properties of hardened concrete in terms of compressive, tensile, flexural, and bond strengths.