Random ionic mobility on blended cements exposed to aggressive environments

Two investigative stages are presented in this study, which aim to establish basic standards for the use of calcined paper sludge (CPS) in the stabilization of soils. The soils were stabilized with CPS and with mixtures of CPS and cement (C). The total percentage of binder was between 3 and 6% by weight. The blending ratios (by weight) of the CPS:C mixtures were 50∶50 and 25∶75. The first stage took place in the laboratory, and the second stage, in the field, involved in situ stabilization of 250 m of subgrade using dry-mix methods. The bearing capacity of the stabilized soils was determined in the laboratory. In the second stage, the densities of the subgrade were measured in the field following compaction and deflections at 7 days. Furthermore, the evolution of its unconfined compressive strength (UCS) was measured over 90 days. The results reveal optimal mechanical behavior of the stabilized soil at CPS:C ratios of approximately 25∶75.

The potential stabilization of high calcium wood waste ash (HCWWA) derived from the wood biomass energy production for use as cementitious material using another industrial by-product, silica fume, was investigated. Throughout the study, both HCWWA and DSF were characterized in term of their respective chemical composition and mineralogical phases. Besides, physical characteristics of HCWWA and DSF in terms of particle grading and specific surface area were established in order to evaluate their suitability as for use as constituent material in blended cement. Additionally, compressive strength properties of high strength mortar produced using HCWWA and DSF blended cement were investigated. Results indicated that the use of HCWWA as a partial cement replacement did not have significant adverse effect on the workability of fresh mortar. The enhancement of the compressive of mortar was observed for mortar mixes containing DSF and HCWWA levels of cement replacement up to 16%.

Dual eco-friendly application of silica fume and scoria in cement-based materials through the enhancement of microbially-induced carbonate precipitation

The viability of combining waste slag produced from steel (Basic Oxygen furnace) and iron (Blast Furnace) industry as replacement of cement in cement mortars was investigated. The impacts on the normal consistency, setting times, soundness, compressive strength, microstructure, and durability of cement paste/mortar were studied. The results revealed that the water requirement and the setting time of cement paste increased by the addition of steel slag powder. The optimum content of steel slag and GGBS (ground granulated blast furnace slag) as a combined admixture was 40%. The 28 day compressive strength was comparable, whereas it exceeded the strength of control mortar after 90 days of curing. The microstructure of samples was studied using SEM micrographs, which indicated denser structures of ternary mortars. The durability tests of accelerated carbonation, sulphuric acid resistance, and electrical resistivity showed acceptable results. Life cycle assessment (LCA) of ternary mortar indicated visible decrease in environmental impacts in all categories. Response Surface Methodology (RSM) was adopted to find relation between partial replacement of cement by steel slag and GGBS in ternary blend and compressive strength. This research bestows a new understanding of how industrial wastes can be managed sustainably with imparting additional benefits to the concrete economically.

Mineralogical and morphological changes of calcined paper sludge at different temperatures and retention in furnace

This investigation elucidates the pozzolic characteristics of pastes that contain waste brick from building construction and demolition wastes. The TCLP leaching concentrations of waste brick for the target cations or heavy metals were all lower than the current regulatory thresholds of the Taiwan EPA. Waste brick had a pozzolanic strength activity index of 107% after 28 days. It can be regarded as a strong pozzolanic material. The compressive strengths of waste brick blended cement (WBBC) that contain 10% waste brick increased from 71.2 MPa at 28 days to 75.1 MPa at 60 days, an increase of approximately 5% over that period. At 28 days, the pozzolanic reaction began, reducing the amount of Ca(OH)(2) and increasing the densification. The intensity of the peak at 3640 cm(- 1) associated with Ca(OH)(2) is approximately the same for ordinary Portland cement (OPC) pastes. The hydration products of all the samples yield characteristics peaks at 978 cm(-1) associated with C-S-H, and at ~3011 cm(-1) and 1640 cm(-1) associated with water. The samples yield peaks at 1112 cm(-1), revealing the formation of ettringite. In WBBC pastes, the ratio Q(2)/Q(1) increases with curing time. These results demonstrate that increasing the curing time increases the number of linear polysilicate anions in C-S-H. Experimental results reveal that waste brick has potential as a pozzolanic material in the partial replacement of cement.

Gas sensing based on the dynamic nonlinear responses of a semiconductor gas sensor: dependence on the range and frequency of a cyclic temperature change

The aim of this study is to investigate the characteristics of Textile ETP and Tannery sludges and strength characteristics of cement-sludge mortar. The textile Effluent Treatment Plant (ETP) and tannery sludges have the potential to become a serious environmental burden for Bangladesh in the future because of their high rate of generation, with a very limited safe disposal option. On the other hand, day by day the demand and price of cement are increasing. This study was devoted to evaluate the technical feasibility of utilizing textile ETP and tannery sludges in cement mortar both as separate and mixed modes. An attempt was taken to replace 5%, 10%, 15% and 20% by weight of cement in mortar with textile ETP and tannery sludges both as a separate and mixed modes. To evaluate the characteristics of the textile ETP and tannery sludges, the pH, moisture content, organic matter content, chemical composition (XRF), TCLP (Heavy Metal) tests were studied. The initial and final setting time, compressive strength, tensile strength, and water absorption of mortar by partial replacement of cement by textile ETP and tannery sludges both as separate and mixed modes were studied to evaluate the properties of cement-sludge mortar. It was found that the textile ETP and tannery sludges both as separate and mixed modes can be a replacement of cement up to 10% in cement mortar and can be used for the purposes of S-type of mortar. The textile ETP sludge as a separate and mixed modes of the sludges can be a replacement of cement up to 20% and can be used for the purposes of N-type of mortar.

Fatigue of ThO 2 dispersion strengthened nickel alloy with surface modification by Al + ion implantation : Banerjee, R. and Grummon, D.S. Scr. Metall.23, (8), 1249–1254, Aug. 1989

Thermo-mechanical behaviour of energy piles in overconsolidated clay under various mechanical loading levels and thermal cycles

Evaluation and improvement of pozzolanic activity of andesite for its use in eco-efficient cement

Mechanical, environmental, and economic assessment of sustainable cement mortar using Afghan natural pozzolan as a partial replacement for cement

This study investigates a use of spent bleaching earth pozzolanic, byproduct of biodiesel production, as sustainable substitute in the cement mortar. As a waste material, spent bleaching earth pozzolanic present viable solution for enhances construction materials while reducing environmental impact. The study aims to assess spent bleaching earth pozzolanic effectiveness as a partial cement replacement in a cement mortar, focusing on its effect on material properties and structural performance at varying replacement levels of 10%, 20%, 30%, 40%, and 50%. Tests conducted include the sieving analysis, water absorption, and compressive strength. The results indicate Portland limestone cement in 75 µm pan sieve weighed for 69 g, and a spent bleaching earth pozzolanic weighed for 77 g, with respective indicating a potential for improved particle packing. By increasing the spent bleaching earth pozzolanic in Portland limestone cement with river sand for cement sand brick, reduce the water absorption values of 0%, 10%, 20%, 30%, 40%, and 50% spent bleaching earth pozzolanic for 9.8%, 9.6%, 9.4%, 9.2%, 9.1%, and 9% at 28 days. The packing packed of Portland limestone cement, spent bleaching earth pozzolanic, and river sand showed as spent bleaching earth pozzolanic increased, the water demand slightly decreased, resulting in compressive strength values suitable for load-bearing application. Finding suggest spent bleaching earth pozzolanic effective as binder at 20% replacement, providing enhance performance without compromising cement sand brick strength, thus supporting the material’s potential in the eco-friendly construction. This research contributes to the sustainable utilization of the industrial byproducts, proposing spent bleaching earth pozzolanic as viable ingredient in building materials that balances mechanical properties with environmental benefits.

This paper presents the findings of an investigation into the influence of green-synthesized nano-TiO2 on the characteristics of wood ash (WA) cement mortar. Mortar specimens were prepared by partial replacement of cement with WA (10% by weight) and addition of 1, 2 and 3% nano-TiO2 by weight of binder; using constant water-to-binder ratio (w/b) for all mixtures. The properties evaluated are setting time of the binder and flexural and compressive strength with water absorption of the mortar. The results indicated that addition of 1 and 2% nano-TiO2 reduced setting times of WA cement paste. Also, the flexural and compressive strength of WA cement mortar were higher with the incorporation of up to 2% nano-TiO2. The water absorption of WA cement mortar was reduced when nano-TiO2 was added with 2% incorporation having the best result. The incorporation of NT in WA cement mortar improved its workability and strength characteristics.

The aim of this research work was to investigate the effect of thermal treatment on strength development of self-compacting mortars (SCMs) based on two pouzolanic materials: Natural Pozzolan and calcined paper waste sludge, were used in the binders of SCMs. To evaluate the effect of heat treatment, a serial of the specimens were exposed to room temperature and another serial were exposed to heating regime (at temperature 60°C for a period of 14 h). The fresh and hardened properties of all mortars were evaluated. the obtained result show that the mechanical strength at 14 days of all mortar treated are almost similar or sometimes better to those not treated mortars tested at 28 days, which reduces the curing time for precast elements.