Research On The Performance And Application Of Scoria Lightweight Aggregate Concrete

A natural lightweight aggregate--scoria has a wide distribution in our country at present.Proved by a lot of related engineering practice,structural lightweight aggregate concrete(LWAC)has obvious effects on minimizing structure deadweight,reducing foundation loading and lessening material consumption and traffic,which can bring considerable economic benefits and social benefits.Research and manufacture on structural LWAC has taken shape that LWAC has great advantage on property,economy and environmental protection.Therefore,this paper has made the following work:Scoria in this experiment are derived from Zhangjiakou.On the basis of testing and analysing on a series of physical properties of scoria,optimal mixing ratio of scoria concrete are determined by material characteristics and the project requirements.Besides,this experiment uses expanded polystyrene(EPS)instead of scoria by means of same volume,and has also explored the reasonable process of mixing and pouring shaping.This experiments have carried out a series of experiments of physical and mechanical performance.Concrete with different strength ranking from LC20 to LC30,good workability and density grade of 1800 has been made up by means of orthogonal test.A small amount of scoria are replaced by EPS and the influence of EPS to the strength and heat conductivity of scoria concrete are studied.The results have showed that the water-absorbing quality of scoria have influence on workability,so it had better use pre-wetting LWA.The dry density and cube compressive strength of LWAC reduce with the the increase of the dosage of scoria.EPS can reduce weight of LWAC and improve heat-preservation property to some extent,but it causes serious damage to strength of scoria concrete.This experiments have also researched on the durability of scoria concrete compared with ordinary concrete.The results have showed that scoria concrete without mineral admixtures behave better on early carbonation resistance than ordinary concrete.And using mineral admixtures instead of a small number of cement can result in speeding scoria concrete carbonation and increasing carbonation depth,while reducing its early drying shrinkage deformation significantly.Besides,the drying shrinkage strain of scoria concrete is slightly smaller than ordinary concrete in the early time but larger than that ultimately.Scoria concrete can withstand 250 times freeze-thaw cycle.