Research On Environmental Impact Quantification And Construction Plan Decision Of Sustainable Concrete Construction

Concrete is now one of the most used building materials.Since the reform and opening up,the building industry in China has gained a great development because of the fast development in economic growth and urbanization process.As a result,the consumption of concrete,the main building material,in China is huge.Great consumption of concrete leads to great burden to the environment because supply chain and construction curing activities of concrete cause great amount of negative environmental impact.To improve the environmental performance of concrete buildings,many studies demonstrate that the sustainable concrete construction needs to be applied,including using sustainable concrete materials and using curing measures with less environmental burden.However,current studies of quantifying the environmental impact of construction lack the ability of analyzing construction system with high complexity,diversity of plans and dynamism.Therefore,these studies cannot provide effective decision support for contractors about sustainable concrete construction.To fill this gap,this research integrates discrete event simulation(DES)technique of computer science,environmental impact assessment theory of environmental science,and concrete mechanical properties and concrete maturity analysis technique of material science.These theories and techniques are integrated to build a systematic method to quantifying both the environmental and economic impact of sustainable concrete construction considering the complexity,diversity of plans and dynamism of construction system.The built method is an effective way to provide decision support about sustainable concrete construction for contractors.In sustainable concrete material selection,the construction system has characteristics of complexity.Construction resource,materials,weather and activities have complex impact on construction performance.This complexity hinders the conventional life cycle analysis to quantify environmental impact of specific construction project.To fill these gaps,this research uses DES to simulation the complex logical interactions of construction activities,uncertain analysis theory to deal with the complexity of construction resource and weather,and concrete mechanical properties to analyze the complex impact of different concrete materials on curing activities.These techniques and theories together with the life cycle analysis build a quantification model of sustainable concrete material selection performance.This model can provide decision support for contractors.Concrete material selection in early planning stage of construction has the characteristics of diversity of plans in construction system.Simulating all the alternative plans of sustainable concrete materials to make decision is inefficient because there are too many plans.This research combines simulation and optimization to build a decision support method with high efficiency.The simulationoptimization method can reduce the number of plans that need to be simulated before finding the optimal plans and thus improve the efficiency.Different simulationoptimization methods are suitable for different decisions.To find the most suitable method for sustainable concrete type selection,this research builds and compares three types of simulation-optimization method,including DES-particle swarm optimization(PSO),DES-Artificial Neural Network(ANN)-PSO and DES-simplified model-PSO.The comparison is conducted from the perspective of optimization efficiency and optimization improvement.The results show that the DES-ANN-PSO is the most suitable method for the studied problem.For curing measures decision in actual construction stage,the construction system is dynamic.The conventional life cycle analysis is a static method and cannot analyze the dynamic impact of the changing weather on curing activities.Therefore,a real-time quantification method for performance of curing measures is needed.Previous manual-based quantification methods cannot analyze the dynamic construction-weather system.To fill the gap,this research combines DES,concrete maturity analysis and dynamic weather database to build an automatic calculation and decision model which can predict the effect of curing measures on construction objectives with the construction progress.The model can provide decision support for contractors about curing measures.Based on the proposed methods and models,this research combines DES platform SIMIO,calculation software MATLAB,My SQL database and concrete maturity analysis tool Hett to build the system prototypes,including the sustainable concrete material performance quantification system,sustainable concrete material simulation-optimization system and curing measures performance calculation and decision system.A case study is conducted to examine effectiveness of the proposed theoretical method and the application of the built system prototypes.This research provides more comprehensive,efficient and practical methods for decisions in sustainable concrete construction.The sustainable concrete material selection performance quantification method that connects environmental and economic indicators and includes supply chain and construction phases provides a more comprehensive quantification results and better decisions support for contractors.This method considers the complexity of construction system and fills the gap of conventional environmental impact calculation method and extend the range of environmental quantification to cradle to construction.Simulationoptimization method significantly reduces the time for making decision and improve the efficiency of sustainable concrete material selection.This method enriches the theoretical development of simulation-optimization by applying it in sustainable concrete construction.The curing measures performance quantification and decision method provides a more practical way to choose curing measures with the construction process.This method covers the shortcoming of simulation in analyzing concrete curing process.The contractors can use the proposed methods to select optimal sustainable concrete types in early construction planning stage and optimal curing measures with concrete process to improve the environmental performance of the building construction project.This research builds systematic ways to apply sustainable concrete construction.