Properties of Concrete Using Treated Low-Class Recycled Coarse Aggregate and Blast Furnace Slag Sand

Abstract

Since high quality natural aggregates are becoming scarce, it is important that industrial recycled products and by-products are used as aggregates for concrete. In Japan, the use of recycled aggregate (RG) is encouraged. Since, strength and durability of recycled aggregate concrete is lower than that of normal aggregate concrete, the use of recycled aggregate has not been significant. In order to improve physical properties of concrete using recycled coarse aggregate, blast furnace slag sand has been proposed. Recently, blast furnace slag sand is expected to improve durability, freezing, and thawing damage of concrete in Japan. Properties of fresh and hardened concrete bleeding, compressive strength, and resistance to freezing and thawing which are caused by the rapid freezing and thawing test using liquid nitrogen is a high loader than the JIS A 1148 A method that were investigated. As a result, concrete using treated low-class recycled coarse aggregate and 50% or 30% replacement of crushed sand with blast furnace slag sand showed the best results, in terms of bleeding, resistance to freezing and thawing.

Sensitivity Analysis of Influencing Factors and Two-Stage Prediction of Frost Resistance of Active-Admixture Recycled Concrete Based on Grey Theory–BPNN

“…Recycled-aggregate concrete came into being at the right moment. Recycled aggregate is obtained by crushing and screening waste concrete, and it is made of recycled-aggregate concrete instead of natural aggregate, which can effectively realize the reuse of waste concrete, which can effectively alleviate the dilemma of short supply of sand and stone, and also meet the requirements of today's society for green concrete, and play a positive role in promoting the sustainable development of building resources and the environment [4,5]. It is without doubt that the recycling of waste concrete is a win-win solution, and has extensive application prospects [6][7][8].…”

The Simple Mix Design Method and Confined Behavior Analysis for Recycled Aggregate Concrete

“…Over the past two decades, many researches have studied some salient issues for the practical application of RAC: The production process and the compressive strength prediction are studied in the early stage [5][6][7]; the comprehensive mechanical properties and durability properties are studied over the past decades [8][9][10]; from the components and micro-properties of RAC to the macro-performance of RAC, the properties are studied in recent years [11][12][13][14][15][16][17]. Against the common concrete with natural aggregate, the RAC with a similar mix proportion has a weakened mechanical property and a great dispersion of properties, due to the weakened and uncertainty properties of recycled aggregate [18][19][20].…”