Improvement of shallow foundations rested on saturated loose sand by zeolite-cement mixture: a laboratory study

Abstract

Improvement operation of sands is carried out frequently by cement together with several other additives. Common additives have high manufacturing cost and negative environmental impact during their manufacturing process and recycling in nature. Zeolite as a mineral substance for cement replacement can improve the strength parameter of a treated sand, without the negative de ciencies of the common additives. In this study, Uncon ned Compression Strength (UCS) and small-scale 1g model tests were conducted to evaluate the mechanical features of zeolite-treated sand and to study the behavior of shallow foundations resting on zeolite pad, respectively. The results of this study demonstrate that the UCS of the cemented sand samples increases when the cement is replaced by zeolite at an optimum proportion of 40% with curing times of 14 and 28 days. Adding this amount of zeolite to cemented sand mixture causes an increase in terms of the improvement rate between 40% and 125% and increases the Bearing Capacity Ratio (BCR) of the strip foundation treated by zeolite pad in the range of 11% to 420%. In addition, zeolite pad leads to a decline in the settlement of the treated strip footing from 16% to 86% in terms of the Settlement Reduction Ratio (SRR).

Effect of Zeolite on the Compaction Properties and California Bearing Ratio (CBR) of Cemented Sand

“…Canpolat et al [25] reported that the replacement of 20% cement with zeolite enhanced the strength of the cement paste. Moreover, MolaAbasi et al [26] and Salamatpoor et al [27] expressed that the UCS of the cemented sand increases when the cement is replaced by zeolite at an optimum proportion of 30 and 40%, respectively. It can be concluded that by the cement substitution with 30% zeolite, the presence of Ca(OH) 2 as a product of hydration reaction comes into a balance with the silica and alumina available in zeolite enrolling in the pozzolanic reaction, and all these chemical constituents are entirely consumed to yield CSH and CAH gels, resulting in the maximum CBR.…”

Load-settlement mechanism of strip footings rested on saturated loose sand and improved by zeolite–cement pads

“…Concerning the study by Salamatpoor et al [24], the experimental study involved three dominant equipment, including a frame, a transparent tank (as a rigid box), and measuring instruments. The frame is composed of IPE 18, which is screwed to a rigid foundation with eight M24 bolts.…”

Mitigating the uneven settlement of nearby strip footings on loose saturated sand using concrete pedestals: a model test study

“…Since the inside width of the box was equal to the length of the model foundations, a plain-strain condition was generally maintained [15]. Before conducting the tests, for each test, some preliminary works were required for higher precision, such as calibrating the load cell, dialing gauge, and depleting the piezometer tubes from the air.…”

“…As the width and the length of the testing tank were constant, the relative density was controlled by measuring the height (or volume) and also the weight of each layer. It was considered to reconstitute the model sand deposit at a relative density (D r ) of 302% through a water sedimentation process [15].…”