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Highlights • EAF slag as coarse aggregate substitution decreases compressive strength and sulfate resistance of RCCP. • Replacing natural aggregate by EAF slag increases water absorption and abrasion resistance of RCCP. • 20% fly ash as cement alternative improves compressive strength and durability properties of slag-RCCP at long-term age. • The weathering treatment process reduces the expansive potential of EAF slag. • EAF slag is non-active aggregate by alkali-silica reaction. Abstract This study investigates the effects of electric arc furnace (EAF) slag aggregate and fly ash on compressive strength and durability properties (i.e. water absorption, abrasion resistance, and sulfate resistance) of roller-compacted concrete pavement (RCCP). The EAF slag aggregate as natural aggregate substitution was used at three levels (i.e. 0%, 50%, and 100%) and cement was replaced by fly ash at three ratios (i.e. 0%, 20%, and 40%). The EAF slag aggregate used in this study was exposed to outdoor condition for several months to reduce the volume instability. The RCCP mixing proportions were determined by soil compaction method. The compressive strength of RCCP was examined at 3-, 7-, 28-, and 91-day age. Meanwhile, the water absorption, abrasion resistance, and sulfate resistance of RCCP at 91-day age were used to study the durability properties. Furthermore, the length change of mortar bars made with EAF slag aggregate was measured to evaluate the expansive potential of EAF slag caused by autoclave condition and alkali-silica reaction (ASR) condition. Additionally, X-ray diffraction analysis was offered to identify the crystalline phases of mortar patterns under autoclave and ASR testing condition. The results presented that the compressive strength and sulfate resistance of RCCP containing EAF slag aggregate declined slightly, whereas the water absorption and abrasion resistance increased in comparison to those of traditional RCCP. Besides, the use of fly ash as cement substitution improved the compressive strength of slag-RCCP at long-term age. A replacement of 20% fly ash provided the slag-RCCP fulfilling the strength and durability requirements for pavement. In addition, the expansion in terms of length change of mortar bars indicated that EAF slag aggregate after the proper treatment performed the volume stability under the autoclave condition and ASR test. [ABSTRACT FROM AUTHOR]

This study focuses on combined usage of agro and industrial wastes in developing environment-friendly concrete. Fresh and hardened characteristics of self-compacting concrete (SCC) made of blended cement with sugarcane bagasse ash (SBA, an agro-waste generated during sugar manufacture), granulated blast furnace slag (BFS) and Ordinary Portland cement were examined through an experimental program. Three SCC mix groups (BA10, BA20, and BA30) corresponded with three cement replacing levels of SBA (10%, 20%, and 30%) were developed. For each group, four mixtures associated with four replacement ratios of cement by slag were further employed (0%, 10%, 20%, and 30%). Totally, 12 mixtures incorporating SBA and BFS blended-cement and one reference mix were developed for experiment. Fresh properties of the proposed SCC were evaluated through measurement of the density, slump, slump-flow, V-funnel test, T 500 slump, Box-test, and setting time. In addition, testing of compressive strength, ultrasonic pulse velocity, sulfate attack, water absorption as well as electrical resistivity were conducted for hardened concrete. The testing results indicated that replacing either SBA and/or BFS to OPC in mixtures led to lesser flowability. Compressive strength of sample made of 30% SBA and 30% BFS substituting to OPC were comparable to that of control after 91 days. Moreover, both of SBA and BFS strongly enhanced sulfate attack resistance; and almost SCC samples had a negligible corrosion rate after 28-day ages. [ABSTRACT FROM AUTHOR]

This study aims at employing stainless steel oxidizing slag (SSOS) as fine aggregate, replacing river sand in mortar mixtures with various ratios (e.g. 0%, 25%, 50%, 75%, and 100%). The received slag was left outdoor from 1- to 8 months as a treatment before be used as aggregate. The content of slag expansion source (free lime) was first determined after the end each month of stabilization. The X-ray diffraction (XRD) technique was offered to identify the mineralogical of the treated slag. Next, fresh and hardened properties of the stabilized-slag mortar including flow table, expansion, compressive strength, ultrasonic pulse velocity were examined in laboratory, accordingly. The expansion in term of length change of the slag mortar bars (25 × 25 × 285 mm) was investigated after the autoclave and heating catalytic (100 °C) curing conditions. The results indicated that free lime content is gradually decreased over times when SSOS exposed to air environment and effectively restricted the expansion capacity of the slag mortar. In addition, a higher SSOS replacement ratio a larger expansion is measured on the mortar bars. Meanwhile, a lesser period of slag treatment could make the specimens fracture at a lower level of slag substitution. The expansion of mortar bar under the autoclave is similar to that of about 72–96 h heating catalysis. Moreover, compressive strength of mortar is improved when containing as much as slag in mixtures, although this induces less workability of fresh mortar. [ABSTRACT FROM AUTHOR]

This study aims at employing stainless steel oxidizing slag (SSOS) as fine aggregate, replacing river sand in mortar mixtures with various ratios (e.g. 0%, 25%, 50%, 75%, and 100%). The received slag was left outdoor from 1- to 8 months as a treatment before be used as aggregate. The content of slag expansion source (free lime) was first determined after the end each month of stabilization. The X-ray diffraction (XRD) technique was offered to identify the mineralogical of the treated slag. Next, fresh and hardened properties of the stabilized-slag mortar including flow table, expansion, compressive strength, ultrasonic pulse velocity were examined in laboratory, accordingly. The expansion in term of length change of the slag mortar bars (25 × 25 × 285 mm) was investigated after the autoclave and heating catalytic (100 °C) curing conditions. The results indicated that free lime content is gradually decreased over times when SSOS exposed to air environment and effectively restricted the expansion capacity of the slag mortar. In addition, a higher SSOS replacement ratio a larger expansion is measured on the mortar bars. Meanwhile, a lesser period of slag treatment could make the specimens fracture at a lower level of slag substitution. The expansion of mortar bar under the autoclave is similar to that of about 72–96 h heating catalysis. Moreover, compressive strength of mortar is improved when containing as much as slag in mixtures, although this induces less workability of fresh mortar. [ABSTRACT FROM AUTHOR]

• Ceramic waste aggregate and clay brick waste powder were used to produce the concrete. • The Taguchi method and Box–Behnken design were applied to the experimental design. • The optimal mixture for maximum compressive strength was found. • The durability of concrete with optimal mixtures was studied. This study investigated the compressive strength and durability of concrete containing clay brick waste powder (CBWP) and ceramic waste aggregate (CWA). First, we applied the Taguchi and Box–Behnken design method to find the optimal conditions for ensuring the maximum compressive strength of concrete. We considered three factors, including the amount of CWA, the amount of CWBP, and the water–cement ratio in the concrete mixture, as factors influencing the compressive strength of concrete. Second, we studied the durability of concrete with optimal mixture. The experimental results showed that the factor that most influenced compressive strength was the amount of CBWP as a cement substitute. The amount of CWA had the least effect on compressive strength. Maximum compressive strength was reached when 100% CWA was used as a coarse aggregate. The compressive strength of concrete containing CWA and CBWP decreased after 7 days but increased again after 28 days. Moreover, the use of CWA and CBWP improved the chloride ion permeability and sulphate resistance of the concrete compared to the control concrete. Meanwhile, the concrete containing CWA and CBWP had lower abrasion resistance than the reference concrete. [ABSTRACT FROM AUTHOR]

This paper deals with development of self-compacting concrete (SCC) containing stainless steel oxidizing slag (SSOS) and stainless steel reducing slag (SSRS) – byproducts of the stainless steel makings. The oxidizing slag was employed as fine and coarse aggregates in substituting to conventional materials (sand and gravel) with various percentages (i.e. 0%, 50%, and 100%). Meanwhile, the reducing slag was used as a part of ordinary Portland cement (e.g. 0%, 10%, 20%, and 30%). As a result, a total of 12 mixtures with a fixed water–binder ratio ( w / b = 0.4) were prepared for experiment; and its properties obtained in fresh state including density, flowability, viscosity, passing ability, and setting time and in hardened state such as compressive strength, ultrasonic pulse velocity, rebound hammer, length change, and surface resistivity were examined accordingly. The results indicate that incorporating SSOS aggregates or SSRS cement in SCC mixtures apparently reduces the workability besides effectively enhancing its viscosity. Mixture with SSOS increased shows a higher fresh density than the control, while containing high level of SSRS results in lowering that density. More interestingly, the stainless steel slags-based SCC can accelerate the hardening process, which shortening a setting time of 25% and 36%, corresponding for mixture with 50% and 100% SSOS aggregates. For hardened properties, compressive strength of SCC prepared with SSOS replacement in full exhibits slightly better or at least similar to that of the control, considerable improvement in surface resistivity, and potentially volumetric instability. Strength development models, modifying from ACI-209, have also been provided for the slags-based SCC. In addition, relationships between UPV, rebound number, and electrical resistivity versus compressive strength within 91 days have been further established. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study on self-compacting concrete (SCC) made with stainless steel reducing slag (SSRS). Two kinds of SSRS, being different in the surface area (e.g., 1766- and 7970 cm 2 /g), were employed as filler and cement substitution, respectively. A series of six mixing proportions with a change of SSRS-cement ratio replacing ordinary Portland cement (OPC) from 0% to 50% (increment 10%) were developed for experimental work. The workability, observed via slump flow, slump-flow time ( T 500 ), V-funnel time, and Box-filling tests, and the setting time test were involved for freshly-mixed SCC. The hardening and durability parameters such as compressive strength, ultrasonic pulse velocity (UPV), rebound hammer (RH), water absorption, electrical resistivity, and sulfate resistance were estimated, accordingly. The testing results indicate that the workability and viscosity can be satisfactory without the use of viscosity modifying agent as usual. The slump flow increased when 20% or less SSRS substituted for OPC; both the T 500 and V-funnel flow time are prolonged for SSRS-based mixtures. Moreover, compressive strength is reduced gradually as the SSRS ratio increases; and SCC made with 30% or less SSRS achieves the required strength of Grade 30 concrete. Also, a strength predictive model, modified from the existing one has been successfully proposed (error range of ±5%). In addition, relationships between compressive strength and UPV, RH number, and electrical resistivity have been successfully established with a high degree of correlation. Finally, a replacement ratio of 10% SSRS could provide the highest sulfate resistivity, evaluating by weight-loss test. [ABSTRACT FROM AUTHOR]

This research investigates the feasibility of using Electric Arc Furnace (EAF) slag aggregate and fly ash in Roller-compacted concrete pavement (RCCP). After treatment process, EAF slag aggregate was examined the potential expansion caused by hydration reactions and alkali-silica reactions. The test results showed that EAF slag aggregate is stable the volume and can be used in concrete. In the RCCP mixtures, EAF slag was used as a substitute for natural coarse aggregates with three percentages (i.e. 0%, 50% and 100%) and cement was partially replaced by fly ash at three content levels (i.e. 0%, 20% and 40%). The optimum moisture content of RCCP mixtures containing EAF slag aggregate and fly ash were determined by the soil compaction method. The unit weight and mechanical properties (i.e. compressive strength, splitting tensile strength and elastic modulus) of RCCP were examined through testing program. As a result, the fresh and hardened unit weight are similar to those of conventional RCCP. Moreover, the compressive strength, splitting tensile strength and elastic modulus of RCCP decreased with increasing EAF slag aggregate ratio at all ages. Nevertheless, the conjunction of EAF slag aggregate and 20% fly ash in the RCCP mixtures improved the mechanical properties in the long-term ages. This study has proved that the RCCP containing EAF slag aggregate and fly ash can be employed to develop pavements as an exposed wearing surface. In addition, a predicting model was proposed to calculate compressive strength of RCCP. [ABSTRACT FROM AUTHOR]

Highlights: [•] A CLSM was prepared with different sand–soil combinations and GGBFS replacement ratios. [•] Increase in slag content may create workability improvement and strength reduction. [•] A large amount of soil in mixture would cause strength reduction and flowability increase. [•] A pulse velocity–compressive strength correlation has been successfully proposed. [ABSTRACT FROM AUTHOR]

Highlights: [•] Twelve mixes were made with different SSRS substitution levels and w/b ratios. [•] SSRS can substitute for OPC up to 30% in production of soil-based CLSM. [•] An increase in SSRS ratio resulted in workability improvement, and strength reduction. [•] An analytical model for predicting the strength has been successfully proposed. [•] Compressive strength of the CLSM can be evaluated via UPV test with high reliability. [Copyright &y& Elsevier]

Highlights: [•] Concrete made with recycled concrete aggregate (coarse and fine). [•] Concrete rubble was replaced by clay brick and tile with ratio from 0% to 67%. [•] Reduction of slump, strength and elastic modulus compared to normal concrete. [•] Insignificant changes in parameter of concrete as raising the brick and tile content. [Copyright &y& Elsevier]