绿色建造下预拌混凝土原材料市场发展趋势

Development Trend on Raw Materials Market of Ready-Mixed Concrete under Green Construction

面对泵送混凝土的传统原材料资源枯竭、生产过程能耗大、碳排放高、污染严重等情况以及中国土木工程行业实施绿色建造的大趋势,各种新的原材料逐渐被开发和推广,其质量、产量、社会认可度逐渐提高。优质天然河砂和卵石在原产地供不应求,而老旧淤塞河道中尚可开采;使用大粒径天然卵石、石灰石、建筑垃圾等为原料生产的碎石和机制砂将成为新的替代品。水泥、粉煤灰、粒化高炉矿渣粉等原材料在生产企业进行转型升级并倾向于在交通便利地区集中建厂的过程中,导致平原、丘陵、山地等区域间供应不均衡的问题,因此,需根据施工所在地的供料情况,采取就地取材的策略。聚羧酸型缓凝高效减水剂以其高效、经济、相容性高、施工方便等优点已普及市场,还需进一步提升与机制砂等材料的适应性;而钙系和镁系膨胀剂对混凝土的补偿收缩需确保与混凝土收缩同步以控制收缩裂缝并避免结构胀裂。配制泵送混凝土需站在建筑全寿命周期的高度考察和改进各种原材料的性能并充分发挥原材料之间的组合效应。

In the face of resource depletion,high energy consumption in production,high carbon emissions,and serious pollution brought by traditional pumpcrete raw materials,a variety of new raw materials have been gradually developed and promoted to conform with the green construction promoted by China’s civil engineering industry,witnessing a stable increase in quality,output,and social recognition.High-quality natural river sand and pebbles are in short supply at the origin,and they can be explored in old silted river channels.Gravel and manufactured sand produced using large particle size natural pebbles,limestone,construction waste,and others as raw materials will become new substitutes.In the transformation and upgrading of production enterprises which tend to build factories in areas with transportation convenience,raw materials including cement,fly ash,and granulated blast furnace slag powder will cause uneven supply in plains,hills,mountains,and other terrains.Therefore,it is required to use local materials according to the situation in the construction site.Polycarboxylic set retarding superplasticizer,though already popularized in the market for its high efficiency,low cost,high compatibility,and convenience in construction,still needs to be more compatible with manufactured sand and other materials.The compensation shrinkage of concrete by calcium and magnesium expansion agents should be synchronized with concrete shrinkage to control shrinkage cracks and avoid structural cracking.In the preparation of pumpcrete,the investigation at the height of the life cycle of buildings,the improvement of the performance of various raw materials,and the utilization of the combination effects of raw materials are all necessary.