خواص الوحدات الخرسانية الجاهزة الصب المنتجة باستخدام ركام ناعم ذو محتوى الاملاح اعلى من 0.5 %

Abstract

At the last period, the problems of the pre-cast concrete units have beenincreased rapidly due to its unconformity to the adopted specifications withregards to sulphate content. The high content of sulphate in Iraqi fine aggregatein many aggregate quarries, which are out of the Iraqi standard specificationlimits, causes many difficulties for most pre-cast concrete units Factories toprovide an acceptable fine aggregate with regards to sulphate content.This study has been conducted to assess the possibility of using fineaggregate with sulphate content higher than the upper limit of the Iraqi standard(0.5%) to produce pre-cast concrete units: hollow concrete block and pavingconcrete brick, where the total amount of sulphate has been controlled bydecreasing the fine aggregate content in the adopted mixes.The tests are conducted on reference mix with an acceptable fineaggregate according to the Iraqi standard (with regards to sulphate content) andthree mixes with fine aggregates contain (1.19, 1.90 and 2.47%) of sulphaterespectively. The hollow concrete block and paving concrete brick are producedfrom all these mixes.The results indicate the possibility of using unacceptable fine aggregate(those with sulphate content higher than 0.5%) to produce an acceptable hollowconcrete block and paving concrete brick according to Iraqi specifications. Thiscould be done by reducing the fine aggregate content in the mixtures within aspecific limit.