Research On Comprehensive Evaluation Of Green Building Materials Based On Analytic Hierarchy Process-entropy Weight Method

According to calculations by the China Construction Materials Federation,in 2020China’s building materials industry will account for about 13% of the country’s total carbon dioxide emissions.This is mainly due to the fact that traditional high-pollution building materials account for a relatively large proportion of the building materials market in China,coupled with the slow development process of new low-carbon,environmentally friendly and high value-added building materials.For example,cement,flat glass,building sanitary ceramics and other traditional building materials not only consume a lot of energy every year,but also emit a lot of carbon dioxide.Therefore,promoting the development and application of green building materials has become one of the national tasks for high-quality development in recent years.At present,the development of green building materials in China is still in its initial stage and faces many problems.This paper addresses the current situation that there is a wide range of green building materials on the market and a lack of a unified scientific evaluation system.Four common green building materials,namely aerated concrete blocks,autoclaved fly ash bricks,concrete hollow blocks and foam concrete blocks,are used as evaluation objects.By referring to the domestic literature on the evaluation of green building materials,a comprehensive evaluation model of green building materials was constructed based on the hierarchical analysis method,entropy weight method and fuzzy comprehensive evaluation method,and finally a comprehensive evaluation of several materials was carried out.The main research work of this thesis is as follows:Firstly,the whole life cycle assessment method is used to analyse the environmental input and output relationship of building materials throughout their life cycle.In the five stages of raw material collection,production,construction,maintenance and dismantling,building materials are accompanied by the input of resources and energy,which are then exported to the environment in the form of pollutants.These pollutants mainly include waste residues,waste water and waste gas.Secondly,the literature on the evaluation of green building materials in China is analysed in depth,so that the principles for the establishment of the evaluation system are put forward.Then it is pointed out that the establishment of the evaluation system should not only include the environmental attributes of building materials,but also cover the economic evaluation,functional evaluation,health evaluation and social evaluation of building materials,which provides ideas for the evaluation study of green building materials.Again,to determine the indicator weights,this paper adopts a combination of assignment weights to arrive at the final weights.The subjective weights are derived from the hierarchical analysis method and the objective weights are obtained from the entropy method.Unlike previous studies,a consistency test was conducted to check the suitability of the weights obtained from the two weighting methods before combining them.The consistency of the weights obtained by the two assignment methods was tested by calculating Spearman rank correlation coefficients,and all correlation coefficients were between 0 and1,and the consistency was satisfied.Finally,the weights obtained by the two assignment methods were combined in a linear weighting way to make the weights more scientific and reasonable.Finally,a comprehensive evaluation model of green building materials based on the fuzzy comprehensive evaluation method was constructed.And several common green building materials were selected and applied to the model to verify the practicality and accuracy of the model.It has certain reference value for people to study the comprehensive evaluation of green building materials in the future.