4.3.2. Critical Barriers in the KSA

The experts in the KSA indicated that the top seven barriers to sustainable C&DWM are B4, B3, B6, B7, B8, B5, and B1. Despite these barriers, the country has moderate RI values (0.50–0.60), the plurality of them is a major challenge to adopt feasible approaches to tackle the barriers. Identification of these barriers can support the efforts of decision makers in the Kingdom to meet their 2030 Vision. There are no data available on C&DW characterization [75]. Despite the fact that contractors play an important role in collecting C&DW from their sites by licensed waste haulers who are subcontracted to perform this task, the subcontractors usually dispose of these wastes indiscriminately in unapproved sites or by the roadsides, resulting in environmental and visual pollutions, and blockage to roads and drainage [2].

### 4.3.3. Critical Barriers in Egypt

The C&DWM challenges are not different in Egypt compared to the KSA and Ghana, as C&DWM is a major problem in the construction industry. Consequently, experts who responded to the study questionnaire identified seven strong barriers to sustainable C&DWM in Egypt. These barriers are B4, B11, B8, B7, B5, B3, and B6. The remaining barriers were regarded as moderate level barriers. Recently, Waste Management Law No.202 of 2020 has been adopted for waste management including construction and demolition waste in Egypt [76]. The main goals of the law are the development of an integrated municipal, industrial, agricultural wastes, and C&DWM system; to promote reuse; the recycling, treatment, and final disposal of waste; and to manage waste in a way that reduces damage to public health and the environment. The implementation of these policies will ensure effective and sustainable C&DWM in Egypt.

Notwithstanding this, Daoud et al. [77] posit that 5.8 million tons of C&DW is generated annually, which accounts for 6.4% of the total SW generation in Egypt. This figure may not reveal the extent of the problem owing to lack of accurate data on SW generation and characteristics in Egypt [78]. Similar to C&DW disposal in the KSA, C&DW is also usually dumped on roadsides and in open spaces. In the particular case of C&DW, contractors usually find it cheaper to transfer C&DW to illegal sites. This problem is continuing despite the new legislation, and this is due to several reasons including the existence of unregistered construction firms operating without permits, lack of regulatory enforcement, poor C&DW collection and disposal, limited local government participation, and poor financial commitments to C&DWM [77].

#### 4.3.4. Critical Barriers in Ghana

The construction industry in Ghana, as with most others in sub-Saharan Africa, is underdeveloped, relying on imported materials and expertise to function. The relative underdevelopment of the sector is characterized by weak institutions and institution building capacity, hence the limited absorptive capacity for managerial, technology, technological innovations, as well as institutional development [10]. The current study indicates B7, B3, B4, B8, and B6 have the highest range of RI (0.60–0.70) and represent the major barriers to effective and sustainable C&DWM in Ghana. The other barriers are considered

moderate barriers and only B1 is disregarded based on its factor. In this context, previous studies showed that the additional financial cost of providing measures to improve the sustainability of construction works, the government policies, legislation and government commitment, the management of the construction industry, the technical information on sustainable construction, the desire of stakeholders in the construction industry to be committed to change, and congruent goals and objectives represented the main components for successful implementation of sustainable construction in the Ghanaian construction industry [10].

#### *4.4. Common Barriers and Proposed Solutions*

Opinion data from respondents were integrated and analyzed for all the countries studied. Table 2 indicates the descriptive information for the results and the overall ranking of barriers using the Relevance Index method. As can be observed, B4, B3, B7, and B8 are strong major barriers to sustainable C&DWM. However, the other barriers are considered as moderate barriers, with only B10 being considered as a weak barrier and can be disregarded due its low RI value (<0.50). The correlation coefficients of the results have also been determined to get the relationship between the different barriers. Table 3 shows the correlation coefficients, where the values between 0.5 and 1 indicate closely related barriers. The strongest relation has been found between B10 and B11 followed by the relation between B9 and B10. The lowest one has been detected between B1 and B10. These barriers can be mitigated and managed by organizations through proper management and leadership.


**Table 2.** Descriptive statistics of the received data and RI index for the overall countries.

N: Number of valid Respondents, RI: Relative importance index.

Based on the evaluation of the barriers to effective and sustainable C&DWM in the four studied countries, practical solutions to overcoming barriers to effective and sustainable C&DWM have been proposed in Table 4. The proposed solutions to tackle the barriers to effective sustainable C&DWM include cooperation and collaboration among construction companies, providing complete data about the amount of C&DW and their composition, the reuse, recycling and reducing of waste and minimizing its negative impact on the environment, choosing the suitable material that can minimize waste or be reused or recycled, increasing the awareness of the benefits and the procedures used for deconstructing buildings and selective demolition that uses fewer tools and equipment, reduces pollution and toxicity in the removal process and increases the longevity of buildings, enforcing regulations on waste management, stakeholder's involvement in C&DWM, application of sustainability policies in C&DWM, and adoption of integrated waste management.


**Table 3.** Correlation coefficients and *p*-values of the barriers for the overall countries.

C: Correlation, *p*-V.: *p*-Value, \*\* Correlation is significant and strong positive, \* *p*-value is not significant.




**Table 4.** *Cont.*

#### **5. Conclusions**

The large amount of C&DW with poor management has severely affected sustainability. Sustainable construction efforts in some countries have been unsuccessful due to so many barriers to its successful implementation. This study identified sustainability barriers to effective and sustainable C&DWM in four countries (UK, KSA, Egypt, and Ghana). Eleven barriers (institutional fragmentation, lack of fundamental data on C&DW, lack of law enforcement, insufficient attention paid to C&DWM, socio-political, technological, lack of regulation, financial, human resources constraints, construction project characteristics, and rigidity of construction practices) have been identified and ranked by RI. The overall ranking of barriers indicated that the insufficient attention paid to C&DWM, lack of law enforcement, lack of regulation, and financial constraints represent the four major barriers to effective and sustainable C&DWM. Consequently, practical solutions to tackle the barriers have been proposed. The proposed solutions include cooperation and collaboration among construction companies, providing complete data about the amount of C&DW and its composition, enforcing regulations on waste management, stakeholder's involvement in C&DWM, application of sustainability policies in C&DWM, and adoption of integrated waste management. These findings can support decision makers to achieve effective and sustainable C&DWM.

Although this study identified and ranked the barriers to sustainable C&DWM and suggested solutions to tackle these barriers, there are still some limitations to the study. The barriers and suggested solutions were identified based on the literature review. The number of respondents was limited. Future studies should consider more barriers hindering the adoption of building information modeling and increase the number of respondents from different countries to be more reliable and closer to the real conditions.

**Author Contributions:** Conceptualization, A.A.-O., P.A.B., M.M.A.d., N.S., J.O.E., A.A., E.A.-E. and G.W.; Data curation, A.A.-O. and P.A.B.; Formal analysis, M.M.A.d. and N.S.; Investigation, A.A.-O., P.A.B., M.M.A.d. and N.S.; Methodology, A.A.-O., P.A.B., M.M.A.d. and N.S.; Software, A.A.-O., P.A.B., M.M.A.d. and N.S.; Supervision, A.A.-O., P.A.B., M.M.A.d. and N.S.; Writing—original draft, M.M.A.d.; Writing—review and editing, M.M.A.d. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Acknowledgments:** The authors would like to thank the Deanship of Scientific Research at Shaqra University for supporting this work.

**Conflicts of Interest:** The authors declare no conflict of interest.
