Age Of 28d Research Articles

Study on mechanical properties and damage mechanism of alkali-activated slag concrete

The cement industry has become one of the important sources of greenhouse gas emissions, and the alkali-activated slag (AAS) has the same mechanical properties and lower carbon emissions as cement in the production process. Therefore, it can be used as an alternative binder for low-carbon buildings. The effect of alkali concentration (mass ratio of Na2O to binder) on the macro-mechanical properties and meso-damage mechanism of alkali-activated slag concrete (AASC) under uniaxial compression was investigated in this work. Six kinds of concrete with alkali concentration of 2 %, 4 %, 6 %, 8 %, 10 % and 12 % were prepared. The microscopic characteristics of AASC were characterized by nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), x-ray diffraction (XRD) and x-ray energy dispersive spectroscopy (EDS); the meso-damage evolution mechanism of AASC was discussed by statistical damage theory. The results showed that the peak stress and elastic modulus of AASC specimens increased, and the microstructure became denser with the increase of alkali concentration. However, the mechanical properties of the specimen deteriorated to some extent when the alkali concentration exceeded 6 %; for example, the peak stress decreased by 24.00 MPa when the alkali concentration was increased from 6 % to 12 % at the age of 28d. Based on the statistical damage theory, the effective stress concept was introduced to quantitatively analyze the mesoscopic damage evolution of AASC. Both fracture and yielding damage modes were considered. By exploring the regular changes of the mesoscopic parameters, the connection between the macroscopic mechanical properties and the mesoscopic damage mechanism was established. Based on the above mechanical properties and mesoscopic damage results, the alkali concentration of 6 % can be used as the best mixture proportions of AASC.

Valorization of industrial wastes for sustainable cement-based materials with enhanced chloride binding

Improving the chloride binding capacity of cement-based material can effectively slow down the corrosion of steel bars in concrete. This study investigated the valorization of two industrial wastes, carbonated sintering red mud (CSRM) and bauxite tailings (BT), as supplementary cementitious materials (SCMs) to enhance the chloride binding capacity of cement-based materials. CSRM and BT were incorporated separately and in combination to prepare cement paste mixtures, replacing 10–30 % of ordinary Portland cement. The bound chloride contents were determined, and the hydration products were characterized using X-ray diffraction and thermogravimetric analysis. Both CSRM and BT promoted the formation of Friedel's salt (FS) through increased aluminum dissolution and conversion of monocarbonate/monosulfate phases. In the early ages, the synergistic effect of CSRM and BT resulted in the highest FS content. At later ages, BT demonstrated superior chloride binding due to its high alumina content facilitating continued FS formation. Furthermore, the adverse effect of CSRM on the composite system was less than that of BT. At 28d age, when the SCMs content was 30 %, the compressive strength of cement-BT system was 34.5 % lower than the control, while the compressive strength of cement-CSRM system was only 20.9 % lower than the control. The findings highlight the potential of valorizing CSRM and BT as sustainable SCMs for developing chloride-resistant cement-based materials.

Enhancement of engineering properties of cement mortars with masonry construction and demolition fines via carbon dioxide utilization, storage and chemical treatment

Shortage of natural sand is severely affecting the global construction industry. The construction sector also generates a substantial amount of construction and demolition (C&D) waste of which masonry wastes constitute a major fraction. Using a circular economy approach, this article explores the feasibility of using treated masonry waste fines (MWF) to replace 75 % of natural sand in Portland cement-based mortars. The treatment consists of a combination of acid washing and CO2 curing to improve the engineering properties of MWF-cement mortars. 0.1 mol/L and 0.5 mol/L (M) H2SO4 were used for chemical treatment of the MWF followed by CO2 curing at 50,000 ppm for 4 hours. Mortars containing treated MWF (MWF-0.1 M-C and MWF-0.5 M-C) were subject to conventional curing (moist curing followed by dry curing at 30 ◦C and 65 % RH) and carbon sequestration via accelerated carbonation curing. Experimental findings suggest that combined treatment with acid and CO2 reduces the pore volume by 13 – 27 % in the pore size range of 10 – 100 nm in MWF. Consequently, mortars with MWF-0.1 M-C and MWF-0.5 M-C show 29 – 30.50 % higher compressive strength at 28-d age and a 29 – 36 % reduction in total shrinkage compared to mortars with similar dosages of as-received MWF. This ensures statistically similar strength and shrinkage as that of the plain mortar (with 100 % natural sand), demonstrating the potential for 75 % sand replacement using treated MWF. Furthermore, carbon sequestration of 16.40 – 19 % by mass of Portland cement is achieved, which contributes to a 15 % enhancement in early strength and reduces the mesoporous volume and shrinkage by up to 43 % and 15–19 % respectively. In summary, the research offers a pathway to recover a “new sand” from C&D wastes , which could be used to manufacture masonry construction products with reduced demand for natural sand.

Modulation of Performance, Plasma Constituents, Small Intestinal Morphology, and Cecum Microbiota in Growing Geese by Dietary Citric Acid Supplementation.

To investigate the efficiency and optimum inclusion level of CA in growing geese diets on performance, plasma constituents, and intestinal health, 240 healthy female geese at the age of 28d were randomly allotted six treatment diets incorporated with 0, 0.8, 1.6, 2.4, 3.2, and 4% CA. Each treatment group consisted of five replicates and eight birds per replicate. The findings demonstrated that 3.2% CA supplementation resulted in improved growth performance (ADG, ADFI, and FBW) (p = 0.001), and geese who received CA also showed lower body fat contents (p < 0.05) than the control group. Moreover, geese from the 2.4% and 3.2% CA group had the highest plasma glutathione peroxidase and insulin-like growth factor 1 levels compared to the other groups (p < 0.05). A microbial diversity analysis of the cecum conducted by 16S rDNA sequencing revealed that 3.2% CA supplementation showed a significantly higher abundance of beneficial bacteria (Muribaculaceae, CHKCI001, Erysipelotricha-ceae_UCG_003, and UCG_009) (p < 0.05) and a lower abundance of harmful bacteria (Atopobiaceae, Streptococcus, Acinetobacter, Pseudomonas, and Alistipes) (p < 0.10). Collectively, our results revealed that dietary supplementation with 3.2% CA had several benefits on the performance and physiological health of growing geese by promoting nutrients metabolism, improving antioxidant capacity, and modulating cecum microbiota.

Effects of carbonation degree on the hydration reactivity of steel slag in cement-based materials

In order to understand the essential relationship between the carbonation treatment and hydration performance of steel slag, the microstructures and reactivities of steel slag supplementary cementitious materials (SCMs) with low and high carbonation degrees were investigated comparatively. Results indicated that carbonation reconstructed the microstructures of steel slags, by forming calcite and SiO2 gel, which increased the specific surface area and changed the hydration reactivities. Low carbonation degree (15 min of carbonation) increased the hydration reactivity of steel slag and corresponding compressive strengths of cement pastes at all test ages. Instead, highly carbonated steel slags (240 min of carbonation) decreased the compressive strength of cement pastes at early age of 3d but increased the compressive strength at late age of 28d. This is attributed to, on one hand, the excessive consumption of calcium silicates reduced the hydration reactivity. On the other hand, the formation of abundant SiO2 gel increased pozzolanic reactivity, facilitating the compressive strength development, particularly at late age.

Promulgation of engineering and sustainable performances of self-compacting geopolymer concrete

This study proposes a user- and eco-friendly methodology to optimize the mix proportion of superplasticizer-free self-compacting alkali-activated concrete (SCAAC). This methodology allows tailoring SCAAC for a desired water-binder ratio, alkaline activator content, and ratio to realize a targeted compressive strength and sustainability index. The validity of the proposed methodology was established via a series of physical tests and ANOVA analyses. The findings indicate that the attained flow properties of the developed SCAAC have significantly improved, i.e., from 490 to 705 mm for mixes of water/binder ratio of 0.45–0.65. The compressive strength results indicates that the water/binder ratio of 0.45 possess 46 MPa at the curing age of 28-d, whereas the water/binder ratio of 0.65 possess a 28-d strength of 39 MPa. The present work proposes the guidelines for the production of SCAAC, since there is no guidelines or standards for SCAAC. To showcase the proposed methodology, this study concludes with a step-by-step procedure for arriving at an optimized design mix for a superplasticizer-free Fly Ash Ground Granulated Blast Furnace Slag (FA-GGBS) based SCAAC. Furthermore, sustainability index (Cost, Carbon and Energy efficiency) analysis was performed for the SCAAC mixes with and without SP. From the analysis it is found that an increase in the SP dosage from 1 to 6% increases the cost of the production of the mix. Also, it increases the energy demand for its production and liberates huge amount of carbon dioxide in the open atmosphere.

Preparation of water-quenched manganese slag and fly ash ultrafine mineral admixture and its application in UHPC

Abstract In this paper, S95 grade ultrafine mineral admixture (UMA) was prepared by water quenched manganese slag and fly ash 1:1 compound mechanical ball milling to a specific surface area of 714 m2/kg. Its activity index was 86.8% at 7d and 96.3% at 28d. The S95 UMA prepared by ball milling has the characteristics of small particle size, high specific surface and high activity. Mixing with powders of different particle sizes, such as cement and silica fume (SF), is helpful to improve particle gradation, reduce its pore structure and increase its compacting property for ultra-high performance concrete (UHPC) whose raw materials are fine aggregate. UHPC was prepared by using the obtained UMA based on orthogonal test. The effects of different factors on the workability, mechanical properties, hydration heat and microstructure of UHPC were studied. The results show that when the SF content is 10%, the mineral admixture content is 10%, the binder–sand ratio is 1.1, and the water–binder ratio is 0.17, the fluidity of UHPC slurry can reach 261 mm, the compressive strength of 7d and 28d age can reach 128 MPa and 154.6 MPa, respectively. The hydration heat release of cementitious materials in 3d was 139.8 J/g. In terms of solid waste resource utilization, S95 grade UMA prepared by water-quench manganese slag and fly ash can replace 10% SF for the preparation of UHPC. It can not only solve the utilization problem of high added value of water quench manganese slag but also reduce the preparation cost of UHPC to a certain extent.

Activation and Application of Wet Shotcrete Concrete with Coal Gasification Slag Aggregate

By analyzing the shortcomings of the existing dry shotcrete process in the coal mines and the shortage of natural sand and gravel resources, it is proposed to use coal gasification slag to replace all natural sand and gravel in the preparation of wet shotcrete. Coal gasification slag has alkali-activated cementitious activity, and its strength as an aggregate in cement mortars still shows significant growth after 28d of age. First of all, the gasified slag aggregate cement mortar was mixed with calcium carbide residue to further stimulate its activity, and the effect law of different amounts of calciumcarbide residue on mortar strength was studied. The results showed that the mortar strength increased continuously with the increase of calcium carbide residue admixture, and the mortar strength increased slowly after the admixture reached 8%. With 8% admixture, the flexural strength at 90d age increased by 58.9%, and compressive strength increased by 13.6% compared with 28d age. MIP, XRD and SEM microscopic analyses showed that the incorporation of CCR promoted the alkali-activated cementation reaction of the gasified slag aggregate, eliminated the oriented aggregation of calcium hydroxide at the cement-aggregate interface, improved the interfacial bonding, and significantly reduced the percentage of harmful pores (50-200 nm) and more harmful pores (>200 nm) in the mortar, which explained the microscopic mechanism of the significant increase in mortar strength. Then the mining wet shotcrete was prepared with coal gasification slag as aggregate and calcium carbide residue as cementing material, and the 28d compressive strength reached 34.8MPa, which significantly improved the concrete strength and ensured the stability of the coal mine roadway support.

Study on Properties of Graphene Oxide Modified Recycled Cement-Based Composites

Based on the replacement of natural sand by recycled fine aggregate of construction waste, the comprehensive physical properties and hydration mechanism of graphene oxide (GO) modified recycled cement-based composites (RCBC) were studied. The RCBC was prepared by ultrasonic dispersion GO and vibration stirring. The results show that the flexural and compressive strength of the RCBC modified by 0.03%GO at 7d age increase by 16% and 21% respectively, the flexural strength and compressive strength of RCBC modified by 0.02% GO at 28d age increase by 13.7% and 13.6% respectively. Good weather resistance and the freeze-thaw performance at age, Cl- contents is less than 0.06%. The radioactive detection results of GO/RCBC is IRa = 0.08 and Ir = 0.15, which belongs to Class A building materials. The hydration mechanism of the prepared GO/RCBC was studied by XRD, TG-DTA, SEM, and other means. The results show that GO promotes the formation of ettringite (AFt), calcium silicate hydrate (C-S-H) and the transformation of AFt and calcium hydroxide (CH) crystal form, thus improving the comprehensive properties of RCBC.

The Electromagnetic Wave Absorbing Property of Dual-Layer Cement Matrix Composites Based on the Principle of Electromagnetic Energy - Thermal Energy Conversion

Based on the application of stealth technology in actual engineering projects, and according to the theory that when electromagnetic waves (EMW) pass through different wave absorbing materials, they will undergo resistance loss, dielectric loss, and magnetic loss, and the electromagnetic energy will be converted into thermal energy, this paper designed and developed a dual-layer EMW-absorbing Cement Matrix Composites (CMC) combining with the principle of impedance matching, and proposed to take cement paste mixed with expanded perlite as the matching layer of the newly developed material, and aggregate and nanomaterials as its wave absorbing layer. The aggregate was prepared by mixing 15wt.% 38μm Fe3O4 powder and 10wt.% 500nm SiC powder into the clay powder to produce cement raw pellets and calcine them at 1190℃, the fabricated aggregate has obvious dielectric loss and magnetic loss to EMW, and its crushing resistance strength can reach 13.7MPa. For the dual-layer test pieces made of the prepared aggregate and 2wt.% Conductive Carbon Black (CCB), within 8-18GHz frequency band, the bandwidth with a reflectivity lower than -10db reached 9.5GHz, the bandwidth with a reflectivity lower than -12db reached 7.55 GHz, and its maximum reflection loss reached -19.56db. In addition, the prepared CMC exhibited good mechanical properties, and its compressive strength reached 50.7MPa at the age of 28d.

Effect of ultra‐high molecular weight polyethylene fiber on the early mechanical strength and shrinkage crack resistance of concrete

AbstractThis study investigates the early mechanical strength, and shrinkage crack resistance of ultra‐high molecular weight polyethylene (UHMWPE) fiber concrete with different lengths and contents. The microstructure of UHMWPE fiber concrete is investigated by scanning electronic microscope (SEM) to analyze the distribution and mechanism of action of UHMWPE fiber in concrete. The mechanical strength results indicate that the compressive strength and splitting tensile strength of concrete increase first and then decrease by adding fibers. The maximum compressive strength and splitting tensile strength at age of 28d are 42.9 and 3.32 MPa, which is 41.1% and 55.9% higher than that of the benchmark group. The SEM results show that when the UHMWPE fiber content is small, the fibers are evenly distributed in concrete and tightly bonded to the matrix. While the fibers will agglomerate and entangle with the increase of the fiber content, the results of shrinkage resistance test demonstrate that the 12 mm fiber with 0.24% fiber volume content can obtain the best shrinkage crack resistance.

Research on mechanical properties and micro-mechanism of Engineering Geopolymers Composites (EGCs) incorporated with modified MWCNTs

Fly ash-based geopilymers have been considered as a promising alternative for the development of high-ductility and eco-frindly engineered materials. In this study, high ductility EGCs were prepared with the incorporation of polyvinyl alcohol (PVA) fiber and modified multi-wall carbon nanotubes (MWCNTs). The compression, flexural and four-point bending tests were used to evaluate the mechanical behaviors of EGCs. The relationship between the ultimate tensile strain and the mid-span displacement was discussed. Meanwhile, the micro-structure and morphology of EGCs were researched using the field emission scanning electron microscopy(FESEM) analysis. The experimental result showed that the compressive and flexural strength of modified geopolymers containing 0.10% modified MWCNTs and 2.00% PVA fiber at curing age of 28d reached maximal value(38.43 MPa and 7.75 MPa). Meanwhile, the uniaxial tensile strain of EGCs also reached maximal value(8.02%), and the corresponding cracking strain, cracking stress and ultimate tensile stress were 0.08%, 2.00 MPa and 4.70 MPa, respectively. In addition, the computing result of ductility indexes and residual strength indexes were well related with corresponding requirements of the deal elastoplastic material. And the four-point bending test could be employed to evaluate the special mechanical properties of uniaxial tensile test. Most importantly, the mechanism of anti-inferiority of EGCs was explained and analyzed from the point of view of microscopic perspective and mesoscopic perspective, and a new mechanism for the modification of PVA fiber and modified MMWCNTs was revealed.

Experimental study of axial compression behavior of circular concrete-filled steel tubes after being loaded at an early age

This paper presents an experimental study on the effects of very early age loading of concrete-filled steel tubular (CFST) short columns on their long-term axial compression behaviors. The specimens include CFSTs wrapped in FRP (fiber reinforced polymer) cloths and bare CFSTs. When concrete is at an age of 1d, 2d or 3d, the circular CFST column specimen is loaded with axial compression, unloaded after reaching the peak value, and then put into the curing room to continue curing. At the age of 28d, the axial compression bearing capacity is tested and the load–displacement curve is obtained. In the tests, five CFST columns are set as the control group, which are directly cured until 28d. The effects of initial loading age, steel tube wall thickness and constraint level are investigated. The results show that very early age loading can improve the long-term load bearing performance of CFST columns. For the configurations applied in the present study, the ultimate bearing capacity are increased by 1.01% to 24.59%, the yield loads by 2.33% to 52.53%, and the combined elastic moduli are also increased.

Analysis of Factors Affecting Permeability of Cement-bentonite Mud Impervious Wall

The permeability coefficient of the cement-bentonite mud anti-seepage wall is measured by triaxial permeability test (100kPa confining pressure 80kPa osmotic pressure), variable head permeability test and one-dimensional consolidation test (100kPa consolidation pressure). Under the conditions of different indoor mixing proportions, the effects of water-cement ratio, water bentonite ratio, curing age, and a small amount of silty clay soil on the permeability of the impervious wall were studied. The test results show that: (1) The average value of the ratio of the permeability coefficient of the variable head test and the triaxial permeability test is 16.75 and 16.73 at the age of 28d and 60d, respectively, and the coefficient of variation is 0.27 and 0.35, respectively; The average value of the ratio of the permeability coefficient of the one-dimensional consolidation test and the triaxial permeability test was 1.20 and 1.21 at the age of 28d and 60d, respectively, and the coefficients of variation were 0.24 and 0.17, respectively. (2) When the water-cement ratio is between 5.88 and 3.85 and the water-bentonite ratio is between 7.14 and 3.85, the permeability coefficient decreases significantly with the increase of age. The ratio of the permeability coefficients at 60d and 28d in age is not significant depending on the test method. (3) When the water-cement ratio and water-bentonite ratio in the mud are certain, the silty clay is blended, and the water-soil ratio decreases from 50 to 10, and the permeability coefficient decreases linearly.

Test Research on the Strength of Ni-Fe Slag Powder Soil-cement at Early-ages

In order to study the effect of incorporation of Ni-Fe slag powder into soil-cement on its early strength, the unconfined compressive strength test and SEM test at 7d age and 28d age were conducted on the soil-cement with incorporation of 0%, 10%, 20%, 30% and 40% of Ni-Fe slag powder respectively. The test results showed that the soil-cement strength decreased with the increase in the content of Ni-Fe slag powder, especially at the age of 7d, the soil-cement strength decreased significantly, and the failure strain was also large, showing greater plasticity; at the age of 28 days, the reduction rate of soil-cement strength gradually decreased. Therefore, the contribution of Ni-Fe slag powder to the soil-cement strength was very small at the age of 7d, and it only gradually played its role at the age of 28d.

Leaching Behavior of Heavy Metals from Cement Pastes Containing Solid Wastes

The leaching behavior of heavy metals from the cement pastes containing solid wastes including fly ash (FA), or municipal solid waste incineration fly ash (MSWI), was investigated by means of the tank test. Effects of two kinds of curing conditions (standard curing and natural curing) and carbonation on the leaching characteristics of heavy metals were studied. The environmental assessment relating to the leaching of heavy metals was also discussed. Results indicate that the leached heavy metals are mostly produced at early age of 28d, and subsequently decrease sharply to be undetected. Specimens subjected to the standard curing exhibit the lower ∑64d leaching concentrations of heavy metals than those exposed to the natural curing. Specimens under carbonation show the highest ∑64d leaching concentrations of heavy metals, compared with those at the standard curing and the natural curing. The long-term exposure of cement concrete containing MSWI and FA to the water environment may lead to the Cr pollution and the Cd pollution, respectively.

Physico-Mechanical Properties and Durability Aspects of Alkali-Activated Calcareous Fly Ash/Slag Mortars

In this paper, the physico-mechanical properties of alkali-activated mortars (CF/S) containing calcareous fly ash (CF) from the combustion of lignite and ladle furnace slag (S) from the steelmaking process as binders as well as sand and glass cullet as inert material have been studied. The constituents were mixed with the alkaline activator (NaOH:Na2SiO3 was 1:1). The binders and aggregates were used in a ratio 1:3 while a part of sand was replaced by glass aggregates (60%). The specimens (dimensions 40x40x160 mm) of alkali-activated mixtures CF/S: 100/0, 80/20 and 50/50 were cured at 25 °C for 2 days and then were placed in humid environment (95±5 % RH, 25 °C). Then the mechanical strength and porosity at 7-d, 28-d and 90-d age were measured. All of the CF/S specimens exhibited compressive strength around 15 MPa at 28 days. After the 28-d age the specimens of CF/S mortars were exposed to wetting/drying and freeze/thaw cycles to have an estimation of durability of alkali-activated CF/S mortars and compared to the Portland I42.5 cement mortars (PC) of high strength 43 MPa. Mass loss of specimens was measured by weighing them. The results showed that alkali-activated CF/S mortars appear to have similar or slight lower behavior to wetting/drying and freeze/thaw cycles compared to net cement mortars.

Experimental investigation on the compressive strength and shrinkage of concrete with pre-wetted lightweight aggregates

Experimental studies are presented on the influence of three types of pre-wetted lightweight aggregates (PLWA), through their volume fractions and moisture content, on the compressive strength and shrinkage of concrete and expansive concrete. Via integrated thermal analysis, the hydration degree during 7d–28d was found to be increased by the internal curing. The use of PLWA increased the shrinkage at 240d due to the significant increase in the shrinkage deformation during the age of 28d–90d caused by internal curing. The results also suggest that incorporation of 10-Mas. % expansive agent is useful to diminish the shrinkage, especially by its combined use with PLWA. Predictive models for the compressive strength and shrinkage of concrete containing PLWA were discussed and a unified model predicting the compressive strength and shrinkage of concrete containing PLWA was suggested.

Reactive powder concrete reinforced with nano SiO2-coated TiO2

Nano SiO2-coated TiO2 (NSCT) is used to reinforce reactive powder concrete (RPC). The reinforcing mechanisms of NSCT are investigated through thermogravimetry (TG) analysis, X-ray powder diffraction (XRD) analysis, elemental analysis and scanning electron microscope (SEM) observation. The mechanical strengths of the NSCT reinforced RPC (NSCTRRPC) at different curing ages manifest significant increases, especially flexural behaviors. The flexural and compressive strengths of NSCTRRPC at age of 28d achieve increases of 87%/6.69MPa and 12.26%/12.2MPa with respect to RPC without NSCT, respectively. TG analyses suggest that acceleration of cement hydration caused by nucleus effect plays a dominant role in the early days. XRD analyses manifests the NSCT decreases the amount of CH crystals in matrix. This suggests that the NSCT has the pozzolanic effect. In addition, element analysis is indicative that NSCT is uniformly distributed inside the matrix to make the cement matrix more compact, which is in consistent with SEM observations. It is therefore concluded that coating of nano SiO2 at the surface of TiO2 is beneficial for the dispersion of nano fillers in matrix and the pozzolanic effect, thus modifying the microstructures and the mechanical property of RPC.

Investigation of coal bottom ash and fly ash in concrete as replacement for sand and cement

Malaysia produces about 8.5 million tons of coal ash as waste which comprises of bottom ash and fly ash. Reusing such waste which is otherwise sent to landfills is an environment-friendly option. Hence, the major aim of this research study was to investigate their use in concrete to replace sand with bottom ash waste and cement with fly ash. Concrete specimens were prepared incorporating 0, 20, 50, 75 and 100% of bottom ash replacing sand and 20% of coal fly ash by mass, as a substitute for Ordinary Portland cement. Fresh and hardened state properties of the experimental specimens were determined. Results revealed that concrete workability reduced when bottom ash content increased replacing sand. On the other hand, at the early age of 28d, no significant effect was observed in compressive, flexural and tensile strengths of all concrete samples. After curing at 91 and 180d ages, compressive strength of both the experimental and control concrete samples increased significantly but remained almost similar. However, flexural and splitting tensile strengths of the experimental mix containing 75% bottom ash and 20% fly ash exceeded much more than the control sample. Moreover, drying-shrinkage of experimental concrete mixtures containing 50%, 75% and 100% bottom ash and 20% fly ash was lower than the control mix. It is concluded that those experimental concrete mixes can be used in several structures (foundations, sub-bases, pavements, etc.) which will minimize the cost, energy and environmental problems to a great extent.