Key parameters for strength control of rammed sand-cement mixtures Influence of types of portland cement

摘要

The present research aims to quantify the influence of distinct types of Portland cement, amounts of cement, porosity, curing time period and porosity/cement ratio in the assessment of unconfined com-pressive strength (q_u) of rammed sand-cement mixtures. A program of unconfined compression tests considering distinct types of Portland cement (types Ⅰ, Ⅲ and Ⅳ), porosities (η), cement contents (C) and curing time periods (t) was carried out in the present study. It was found that a ratio between porosity and cement [(η/C_(iv)~(-1.5)] applies to all equations that control the strength of blends (for the curing periods and cement types studied here). The q_u values of the specimens moulded for each cement type and curing period were also normalize (i.e. divided by the q_u attained by a specimen with porosity/cement ratio equals to 20). It was found that a single power function adapts well to the normalized values for all the cement type and curing period studied. From a practical viewpoint, this means that carrying out only one (1) compression test with a specimen moulded with a specific cement time and cured for a given time period, allows the equation that controls the strength for distinct porosity and cement content to be determined.