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This paper presents a conceptual model of effective subcontractor development practices to guide general contractors' development of a network of high-performing subcontractors (SCs) for Leadership in Energy and Environmental Design (LEED) projects.

Drawing from supplier development theories and practices in the manufacturing sector, a mixed interpretivist and empirical methodology is adopted to examine the body of knowledge within literature for conceptual model development. A self-reporting survey questionnaire with a five-point Likert scale is used to assess 30 construction professionals' perceptions of the effectiveness of 37 SC development practices classified into five categories. Descriptive statistics, weighted means, and t-tests are used for data analysis.

SC prequalification, commitment, incentives, evaluation and feedback practices can be effective in generating high-performing SCs. Practices that require more direct involvement and linkages between GC and SC are perceived to be less effective.

Theoretical contributions include a framework to foster future research to advance knowledge and understanding to enhance the adoption of SC development practices in the construction sector.

Implementation of ranked SC development practices can equip GCs with a network of high-performing SCs for improved competitive advantage and revenues.

The proposed conceptual model expands discussions on the modification of supplier development theories and practices currently utilized in the manufacturing sector toward their application in the construction sector. This research differs from previous research, which primarily focused on the manufacturing sector.

The purpose of this study is to explore the feasibility of utilizing agricultural (almond shell, rice husk and wood) waste biochars for partial cement replacement by evaluating the relationships between the physiochemical properties of biochars and the early-age characteristics of cement pastes.

Biochars are prepared through the thermal decomposition of biomass in an inert atmosphere. Using varying percentages, biochars are used to replace ordinary Portland cement (OPC) in cement pastes at a water/binder ratio of 0.35. Characterization methods include XPS, FTIR, SEM, TGA, BET, Raman, loss-on-ignition, setting, compression and water absorption tests.

Accelerated setting in biochar-modified cement pastes is attributed to chemical interactions between surface functional groups of biochars and calcium cations from OPC, leading to the early development of metal carboxylate and alkyne salts, alongside the typical calcium-silicate-hydrate (C-S-H). Also, metal chlorides such as calcium chlorides in biochars contribute to the accelerate setting in pastes. Lower compression strength and higher water absorption result from weakened microstructure due to poor C-S-H development as the high carbon content in biochars reduces water available for optimum C-S-H hydration. Amorphous silica contributes to strength development in pastes through pozzolanic interactions. With its optimal physiochemical properties, rice-husk biochars are best suited for cement replacement.

While biochar parent material properties have an impact on biochar properties, these are not investigated in this study. Additional investigations will be conducted in the future.

Carbon/silicon ratio, oxygen/carbon ratio, alkali and alkaline metal content, chlorine content, carboxylic and alkyne surface functional groups and surface areas of biochars may be used to estimate biochar suitability for cement replacement. Biochars with chlorides and reactive functional groups such as C=C and COOH demonstrate potential for concrete accelerator applications. Such applications will speed up the construction of concrete structures and reduce overall construction time and related costs.

Reductions in OPC production and agricultural waste deterioration will slow down the progression of negative environmental and human health impacts. Also, agricultural, manufacturing and construction employment opportunities will improve the quality of life in agricultural communities.

Empirical findings advance research and practice toward optimum utilization of biomass in cement-based materials.

The purpose of this paper is to investigate the effect of an admixture, Swine-waste Bio-char (SB), on the water absorption characteristics of cement pastes.

The effect of SB percentages, heat treatment temperatures, water/binder ratios, and age on the water absorption percentages (WAPs) of SB modified cement pastes were investigated using scanning electron microscopy-energy dispersive spectra, FTIR, Brunauer-Emmett-Teller, and laboratory experiments.

The WAPs of cement pastes with SBs produced at the low treatment temperature (LTT) of 340°C and 400°C were significantly lower (p<0.01) than pastes with SBs produced at the high treatment temperature (HTT) of 600°C and 800°C. This was attributed primarily to the more dominant presence of hydrophobic alkyl surface groups from non-volatilized matter in LTT-SBs. This had also resulted in lower surface areas and pore volumes in LTT-SBs. As a result of the volatilization of these labile hydrophobic groups at HTT, HTT-SBs were more hydrophilic and had higher surface areas and pore volumes. Consequently, HTT-SB pastes had higher WAPs and no significant differences (p<0.05) existed between HTT-SB pastes and control pastes. Also, low water/binder ratios and aging reduced water absorption of SB modified cement pastes.

LTT-SBs reduce water absorption and could reduce concrete deterioration; and as such, associated building repair, maintenance, and adaptation costs. Notably, reductions in concrete water absorption will extend the service life of concrete buildings and infrastructures, particularly in unfavorable environmental conditions. The observed benefits are tempered by the current lack of information on the effects of SB on compression strength, workability, and other durability properties.

SB utilization in concrete buildings will enhance swine-waste disposal and reduce negative environmental impacts on swine farming communities; consequently, improving their quality of life.

Current bio-char research is focused on plant-derived bio-char toward soil remediation and contaminant removal, with very limited applications in concrete. This research advances knowledge for developing livestock-derived bio-char, as a PCRM, toward more sustainable and durable concrete structures.

The purpose of this paper is to develop a Housing Eligibility Assessment Scoring Method (HEASM) for low-income Urgent Repair Programs (URPs).

In order to develop a practical HEASM that incorporates the prevailing eligibility assessment criteria for low-income URPs, a case study research approach was adopted. Emergent themes and patterns in predominant eligibility assessment criteria and methods are derived from program documents utilized by a successful State Urgent Repair Program (SURP) and its 42 Community Partners operating in the Southeastern region of the USA. Coupled with interviews and the expert analysis of SURP staff, the quantitative analysis of 11,414 repaired homes and literature reviews were used to categorize predominant eligible housing repairs and costs.

The five key eligibility assessment criteria categories that emerged from the data analysis are: location, owner-occupancy, family needs, housing repair, and estimated repair costs. The framework of the proposed HEASM is guided by these five categories.

URP decision makers are provided with a simple, practical, and objective eligibility assessment method that can be easily modified to accommodate the unique eligibility criteria and local program conditions. This method should improve the eligibility assessment, prioritization, and the eventual selection of qualifying applicants. Consequently, the capacity of URPs to provide funding to their targeted populations with the most critical needs would be enhanced. Insights could drive the impetus to modify existing URP.